# Galaxy Tool XML File

The XML File for a Galaxy tool, generally referred to as the "tool config
file" or "wrapper", serves a number of purposes. First, it lays out the user
interface for the tool (e.g. form fields, text, help, etc.). Second, it
provides the glue that links your tool to Galaxy by telling Galaxy how to
invoke it, what options to pass, and what files it will produce as output.

If you find a bug please report it [here](https://github.com/galaxyproject/galaxy/issues/new).

This document serves as reference documentation. If you would like to learn
how to build tools for Galaxy,
[Planemo](https://planemo.readthedocs.io/en/latest/writing.html) features a
number of tutorials on building Galaxy tools that would better serve that purpose.

## Contents

* [``tool``](#tool)
* [``tool`` > ``description``](#tool-description)
* [``tool`` > ``macros``](#tool-macros)
* [``tool`` > ``edam_topics``](#tool-edam-topics)
* [``tool`` > ``edam_operations``](#tool-edam-operations)
* [``tool`` > ``xrefs``](#tool-xrefs)
* [``tool`` > ``xrefs`` > ``xref``](#tool-xrefs-xref)
* [``tool`` > ``creator``](#tool-creator)
* [``tool`` > ``creator`` > ``person``](#tool-creator-person)
* [``tool`` > ``creator`` > ``organization``](#tool-creator-organization)
* [``tool`` > ``requirements``](#tool-requirements)
* [``tool`` > ``requirements`` > ``requirement``](#tool-requirements-requirement)
* [``tool`` > ``requirements`` > ``container``](#tool-requirements-container)
* [``tool`` > ``required_files``](#tool-required-files)
* [``tool`` > ``required_files`` > ``include``](#tool-required-files-include)
* [``tool`` > ``required_files`` > ``exclude``](#tool-required-files-exclude)
* [``tool`` > ``code``](#tool-code)
* [``tool`` > ``stdio``](#tool-stdio)
* [``tool`` > ``stdio`` > ``exit_code``](#tool-stdio-exit-code)
* [``tool`` > ``stdio`` > ``regex``](#tool-stdio-regex)
* [``tool`` > ``version_command``](#tool-version-command)
* [``tool`` > ``command``](#tool-command)
* [``tool`` > ``environment_variables``](#tool-environment-variables)
* [``tool`` > ``environment_variables`` > ``environment_variable``](#tool-environment-variables-environment-variable)
* [``tool`` > ``configfiles``](#tool-configfiles)
* [``tool`` > ``configfiles`` > ``configfile``](#tool-configfiles-configfile)
* [``tool`` > ``configfiles`` > ``inputs``](#tool-configfiles-inputs)
* [``tool`` > ``inputs``](#tool-inputs)
* [``tool`` > ``inputs`` > ``section``](#tool-inputs-section)
* [``tool`` > ``inputs`` > ``repeat``](#tool-inputs-repeat)
* [``tool`` > ``inputs`` > ``conditional``](#tool-inputs-conditional)
* [``tool`` > ``inputs`` > ``conditional`` > ``when``](#tool-inputs-conditional-when)
* [``tool`` > ``inputs`` > ``param``](#tool-inputs-param)
* [``tool`` > ``inputs`` > ``param`` > ``validator``](#tool-inputs-param-validator)
* [``tool`` > ``inputs`` > ``param`` > ``option``](#tool-inputs-param-option)
* [``tool`` > ``inputs`` > ``param`` > ``conversion``](#tool-inputs-param-conversion)
* [``tool`` > ``inputs`` > ``param`` > ``options``](#tool-inputs-param-options)
* [``tool`` > ``inputs`` > ``param`` > ``options`` > ``column``](#tool-inputs-param-options-column)
* [``tool`` > ``inputs`` > ``param`` > ``options`` > ``filter``](#tool-inputs-param-options-filter)
* [``tool`` > ``inputs`` > ``param`` > ``sanitizer``](#tool-inputs-param-sanitizer)
* [``tool`` > ``inputs`` > ``param`` > ``sanitizer`` > ``valid``](#tool-inputs-param-sanitizer-valid)
* [``tool`` > ``inputs`` > ``param`` > ``sanitizer`` > ``valid`` > ``add``](#tool-inputs-param-sanitizer-valid-add)
* [``tool`` > ``inputs`` > ``param`` > ``sanitizer`` > ``valid`` > ``remove``](#tool-inputs-param-sanitizer-valid-remove)
* [``tool`` > ``inputs`` > ``param`` > ``sanitizer`` > ``mapping``](#tool-inputs-param-sanitizer-mapping)
* [``tool`` > ``inputs`` > ``param`` > ``sanitizer`` > ``mapping`` > ``add``](#tool-inputs-param-sanitizer-mapping-add)
* [``tool`` > ``inputs`` > ``param`` > ``sanitizer`` > ``mapping`` > ``remove``](#tool-inputs-param-sanitizer-mapping-remove)
* [``tool`` > ``request_param_translation``](#tool-request-param-translation)
* [``tool`` > ``request_param_translation`` > ``request_param``](#tool-request-param-translation-request-param)
* [``tool`` > ``request_param_translation`` > ``request_param`` > ``append_param``](#tool-request-param-translation-request-param-append-param)
* [``tool`` > ``request_param_translation`` > ``request_param`` > ``append_param`` > ``value``](#tool-request-param-translation-request-param-append-param-value)
* [``tool`` > ``request_param_translation`` > ``request_param`` > ``value_translation``](#tool-request-param-translation-request-param-value-translation)
* [``tool`` > ``request_param_translation`` > ``request_param`` > ``value_translation`` > ``value``](#tool-request-param-translation-request-param-value-translation-value)
* [``tool`` > ``outputs``](#tool-outputs)
* [``tool`` > ``outputs`` > ``data``](#tool-outputs-data)
* [``tool`` > ``outputs`` > ``data`` > ``filter``](#tool-outputs-data-filter)
* [``tool`` > ``outputs`` > ``data`` > ``change_format``](#tool-outputs-data-change-format)
* [``tool`` > ``outputs`` > ``data`` > ``change_format`` > ``when``](#tool-outputs-data-change-format-when)
* [``tool`` > ``outputs`` > ``data`` > ``actions``](#tool-outputs-data-actions)
* [``tool`` > ``outputs`` > ``data`` > ``actions`` > ``conditional``](#tool-outputs-data-actions-conditional)
* [``tool`` > ``outputs`` > ``data`` > ``actions`` > ``conditional`` > ``when``](#tool-outputs-data-actions-conditional-when)
* [``tool`` > ``outputs`` > ``data`` > ``actions`` > ``action``](#tool-outputs-data-actions-action)
* [``tool`` > ``outputs`` > ``data`` > ``discover_datasets``](#tool-outputs-data-discover-datasets)
* [``tool`` > ``outputs`` > ``collection``](#tool-outputs-collection)
* [``tool`` > ``outputs`` > ``collection`` > ``filter``](#tool-outputs-collection-filter)
* [``tool`` > ``outputs`` > ``collection`` > ``discover_datasets``](#tool-outputs-collection-discover-datasets)
* [``tool`` > ``tests``](#tool-tests)
* [``tool`` > ``tests`` > ``test``](#tool-tests-test)
* [``tool`` > ``tests`` > ``test`` > ``param``](#tool-tests-test-param)
* [``tool`` > ``tests`` > ``test`` > ``param`` > ``collection``](#tool-tests-test-param-collection)
* [``tool`` > ``tests`` > ``test`` > ``repeat``](#tool-tests-test-repeat)
* [``tool`` > ``tests`` > ``test`` > ``section``](#tool-tests-test-section)
* [``tool`` > ``tests`` > ``test`` > ``conditional``](#tool-tests-test-conditional)
* [``tool`` > ``tests`` > ``test`` > ``output``](#tool-tests-test-output)
* [``tool`` > ``tests`` > ``test`` > ``output`` > ``discover_dataset``](#tool-tests-test-output-discover-dataset)
* [``tool`` > ``tests`` > ``test`` > ``output`` > ``metadata``](#tool-tests-test-output-metadata)
* [``tool`` > ``tests`` > ``test`` > ``output`` > ``assert_contents``](#tool-tests-test-output-assert-contents)
* [``tool`` > ``tests`` > ``test`` > ``output_collection``](#tool-tests-test-output-collection)
* [``tool`` > ``tests`` > ``test`` > ``assert_command``](#tool-tests-test-assert-command)
* [``tool`` > ``tests`` > ``test`` > ``assert_stdout``](#tool-tests-test-assert-stdout)
* [``tool`` > ``tests`` > ``test`` > ``assert_stderr``](#tool-tests-test-assert-stderr)
* [``tool`` > ``help``](#tool-help)
* [``tool`` > ``citations``](#tool-citations)
* [``tool`` > ``citations`` > ``citation``](#tool-citations-citation)


## ``tool``


The outer-most tag set of tool XML files. Attributes on this tag apply to the
tool as a whole.

### Tool profile

List of behavior changes associated with profile versions:

#### 16.04

- Disable implicit extra file collection. All dynamic extra file collection requires a `discover_datasets` tag.
- Disable `format="input"` and require explicit metadata targets (`metadata_source`, `format_source`).
- Disable `interpreter` use `$__tool_directory__`.
- Disable `$param_file` use `configfile`.
- Disable default tool version of 1.0.0.
- Use non zero exit code as default stdio error condition (before non-empty stderr).

#### 18.01

- Use a separate home directory for each job.
- Introduce `provided_metadata_style` with default `"default"` before `"legacy"`.

#### 18.09 

- References to other inputs need to be fully qualified by using `|`.
- Do not allow provided but illegal default values.
- Do not use Galaxy python environment for `manage_data` tools.

#### 19.05

- Change default Python version from 2.7 to 3.5

#### 20.05

- json config files: 
   - unselected optional `select` and `data_column` parameters get `None` instead of `"None"`
   - multiple `select` and `data_column` parameters are lists (before comma separated string)

#### 20.09

- Exit immediately if a command exits with a non-zero status (`set -e`).
- Assume sort order for collection elements.

### 21.09

- Do not strip leading and trailing whitespaces in `from_work_dir` attribute.

### Examples

A normal tool:

```xml
<tool id="seqtk_seq"
      name="Convert FASTQ to FASTA"
      version="1.0.0"
      profile="16.04"
>
```

A ``data_source`` tool contains a few more relevant attributes.

```xml
<tool id="ucsc_table_direct1"
      name="UCSC Main"
      version="1.0.0"
      hidden="false"
      profile="16.01"
      tool_type="data_source"
      URL_method="post">
```
      

### Best Practices

Find the Intergalactic Utilities Commision suggested best practices for this
element [here](https://planemo.readthedocs.io/en/latest/standards/docs/best_practices/tool_xml.html#tools).


### Attributes

Attribute | Details | Required
--- | --- | ---
``id`` | Must be unique across all tools; should be lowercase and contain only letters, numbers, and underscores. It allows for tool versioning and metrics of the number of times a tool is used, among other things. Find the Intergalactic Utilities Commision suggested best practices for this element [here](https://planemo.readthedocs.io/en/latest/standards/docs/best_practices/tool_xml.html#tool-ids). | True
``name`` | This string is what is displayed as a hyperlink in the tool menu. Find the Intergalactic Utilities Commision suggested best practices for this element [here](https://planemo.readthedocs.io/en/latest/standards/docs/best_practices/tool_xml.html#tool-names). | True
``version`` | This string allows for tool versioning and should be increased with each new version of the tool. The value should follow the [PEP 440](https://www.python.org/dev/peps/pep-0440/) specification. It defaults to ``1.0.0`` if it is not included in the tag. Find the Intergalactic Utilities Commision suggested best practices for this element [here](https://planemo.readthedocs.io/en/latest/standards/docs/best_practices/tool_xml.html#tool-versions). | False
``hidden`` | Allows for tools to be loaded upon server startup, but not displayed in the tool menu. This attribute should be applied in the toolbox configuration instead and so should be considered deprecated. | False
``display_interface`` | Disable the display the tool's graphical tool form by setting this to ``false``. | False
``tool_type`` | Allows for certain framework functionality to be performed on certain types of tools. Normal tools that execute typical command-line jobs do not need to specify this, special kinds of tools such as [Data Source](https://galaxyproject.org/admin/internals/data-sources/) and [Data Manager](https://galaxyproject.org/admin/tools/data-managers/) tools should set this to have values such as ``data_source`` or ``manage_data``. | False
``profile`` | This string specifies the minimum Galaxy version that should be required to run this tool. Certain legacy behaviors such as using standard error content to detect errors instead of exit code are disabled automatically if profile is set to any version newer than ``16.01``. See above for the list of behavior changes associated with profile versions. | False
``license`` | This string specifies any full URI or a a short [SPDX](https://spdx.org/licenses/) identifier for a license for this tool wrapper. The tool wrapper version can be indepedent of the underlying tool. This license covers the tool XML and associated scripts shipped with the tool.  This is interpreted as [schema.org/license](https://schema.org/license)). | False
``python_template_version`` | This string specifies the minimum Python version that is able to fill the Cheetah sections of the tool. If unset defaults to 2.7 if the profile is older than 19.05, otherwise defaults to 3.5. Galaxy will attempt to convert Python statements in Cheetah sections using [future](http://python-future.org/) if Galaxy is run on Python 3 and ``python_template_version`` is below 3. | False
``workflow_compatible`` | This attribute indicates if this tool is usable within a workflow (defaults to ``true`` for normal tools and ``false`` for data sources). | False
``URL_method`` | Only used if ``tool_type`` attribute value is ``data_source`` - this attribute defines the HTTP request method to use when communicating with an external data source application (the default is ``get``). | False


## ``tool`` > ``description``

The value is displayed in
the tool menu immediately following the hyperlink for the tool (based on the
``name`` attribute of the ``<tool>`` tag set described above).

### Example

```xml
<description>table browser</description>
```


### Best Practices

Find the Intergalactic Utilities Commision suggested best practices for this
element [here](https://planemo.readthedocs.io/en/latest/standards/docs/best_practices/tool_xml.html#tool-descriptions).



## ``tool`` > ``macros``

Frequently, tools may require the same XML
fragments be repeated in a file (for instance similar conditional branches,
repeated options, etc...) or among tools in the same repository. Galaxy tools
have a macro system to address this problem.

For more information, see [planemo documentation](https://planemo.readthedocs.io/en/latest/writing_advanced.html#macros-reusable-elements)



## ``tool`` > ``edam_topics``


Container tag set for the ``<edam_topic>`` tags.
A tool can have any number of EDAM topic references.

```xml
<!-- Example: this tool is about 'Statistics and probability' (http://edamontology.org/topic_2269) -->
<edam_topics>
    <edam_topic>topic_2269</edam_topic>
</edam_topics>
```




## ``tool`` > ``edam_operations``


Container tag set for the ``<edam_operation>`` tags.
A tool can have any number of EDAM operation references.

```xml
<!-- Example: this tool performs a 'Conversion' operation (http://edamontology.org/operation_3434) -->
<edam_operations>
    <edam_operation>operation_3434</edam_operation>
</edam_operations>
```





## ``tool`` > ``xrefs``


Container tag set for the ``<xref>`` tags.
A tool can refer multiple reference IDs.
	
```xml
   <!-- Example: this tool is seqtk -->
   <xrefs>
	<xref type="bio.tools">seqtk</xref>
   </xrefs>
   <!-- https://bio.tools/seqtk -->
```





## ``tool`` > ``xrefs`` > ``xref``

The ``xref`` element specifies reference
information according to a catalog.


### Attributes

Attribute | Details | Required
--- | --- | ---
``type`` | Type of reference - currently ``bio.tools`` is the only supported options. | True


## ``tool`` > ``creator``

The creator(s) of this work. See [schema.org/creator](https://schema.org/creator).



## ``tool`` > ``creator`` > ``person``


Describes a person. Tries to stay close to [schema.org/Person](https://schema.org/Person).



### Attributes

Attribute | Details | Required
--- | --- | ---
``givenName`` | [schema.org/givenName](https://schema.org/givenName) | False
``familyName`` | [schema.org/familyName](https://schema.org/familyName) | False
``honorificPrefix`` | [schema.org/honorificPrefix](https://schema.org/honorificPrefix) | False
``honorificSuffix`` | [schema.org/honorificSuffix](https://schema.org/honorificSuffix) | False
``jobTitle`` | [schema.org/jobTitle](https://schema.org/jobTitle) | False
``name`` | [schema.org/name](https://schema.org/name) | False
``url`` | [schema.org/url](https://schema.org/url) | False
``identifier`` | [schema.org/identifier](https://schema.org/identifier) | False
``image`` | [schema.org/image](https://schema.org/image) | False
``address`` | [schema.org/address](https://schema.org/address) | False
``email`` | [schema.org/email](https://schema.org/email) | False
``telephone`` | [schema.org/telephone](https://schema.org/telephone) | False
``faxNumber`` | [schema.org/faxNumber](https://schema.org/faxNumber) | False
``alternateName`` | [schema.org/alternateName](https://schema.org/alternateName) | False


## ``tool`` > ``creator`` > ``organization``


Describes an organization. Tries to stay close to [schema.org/Organization](https://schema.org/Organization).



### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | [schema.org/name](https://schema.org/name) | False
``url`` | [schema.org/url](https://schema.org/url) | False
``identifier`` | [schema.org/identifier](https://schema.org/identifier) | False
``image`` | [schema.org/image](https://schema.org/image) | False
``address`` | [schema.org/address](https://schema.org/address) | False
``email`` | [schema.org/email](https://schema.org/email) | False
``telephone`` | [schema.org/telephone](https://schema.org/telephone) | False
``faxNumber`` | [schema.org/faxNumber](https://schema.org/faxNumber) | False
``alternateName`` | [schema.org/alternateName](https://schema.org/alternateName) | False


## ``tool`` > ``requirements``



This is a container tag set for the ``requirement`` and ``container`` tags
described in greater detail below. ``requirement``s describe software packages
and other individual computing requirements required to execute a tool, while
``container``s describe Docker or Singularity containers that should be able to
serve as complete descriptions of the runtime of a tool.





## ``tool`` > ``requirements`` > ``requirement``



This tag set is contained within the ``<requirements>`` tag set. Third party
programs or modules that the tool depends upon are included in this tag set.

When a tool runs, Galaxy attempts to *resolve* these requirements (also called
dependencies). ``requirement``s are meant to be abstract and resolvable by
multiple different systems (e.g. [conda](https://conda.io/), the
[Galaxy Tool Shed dependency management system](https://galaxyproject.org/toolshed/tool-features/#Automatic_third-party_tool_dependency_installation_and_compilation_with_installed_repositories),
or [environment modules](http://modules.sourceforge.net/)).

Read more about dependency resolvers in Galaxy on
[docs.galaxyproject.org](https://docs.galaxyproject.org/en/master/admin/dependency_resolvers.html).
The current best practice for tool dependencies is to target Conda, this is
discussed in greater detail
[here](https://docs.galaxyproject.org/en/master/admin/conda_faq.html).

### Examples

This example shows a tool that requires the samtools 0.0.18 package.

This package is available via the Tool Shed (see
[Tool Shed dependency management](https://galaxyproject.org/toolshed/tool-features/#Automatic_third-party_tool_dependency_installation_and_compilation_with_installed_repositories)
) as well as [Conda](https://docs.galaxyproject.org/en/master/admin/conda_faq.html)
and can be configured locally to adapt to any other package management system.

```xml
<requirements>
    <requirement type="package" version="0.1.18">samtools</requirement>
</requirements>
```

This older example shows a tool that requires R version 2.15.1. The
``tool_dependencies.xml`` should contain matching declarations for Galaxy to
actually install the R runtime. The ``set_envirornment`` type is only respected
by the tool shed and is ignored by the newer and preferred conda dependency
resolver.

```xml
<requirements>
    <requirement type="set_environment">R_SCRIPT_PATH</requirement>
    <requirement type="package" version="2.15.1">R</requirement>
</requirements>
```




### Attributes

Attribute | Details | Required
--- | --- | ---
``type`` | This value defines the type of the 3rd party module required by this tool. | True
``version`` | For requirements of type ``package`` this value defines a specific version of the tool dependency. | False


## ``tool`` > ``requirements`` > ``container``


This tag set is contained within the 'requirements' tag set. Galaxy can be
configured to run tools within [Docker](https://www.docker.com/) or [Singularity](https://www.sylabs.io/singularity/)
containers - this tag allows the tool to suggest possible valid containers for this tool. The contents of the tag should
be a container image identifier appropriate for the particular container runtime being used, e.g.
``quay.io/biocontainers/fastqc:0.11.2--1`` for Docker or ``docker://quay.io/biocontainers/fastqc:0.11.2--1``
(or alternatively ``/opt/containers/fastqc.simg`` if your Galaxy installation will be loading the image from a filesystem path)
for Singularity. The ``requirements`` tag can contain multiple ``container`` tags describing suitable container options, in
which case the first container that is found by the Galaxy container resolver at runtime will be used.

Example:

```xml
<requirements>
  <container type="docker">quay.io/biocontainers/fastqc:0.11.2--1</container>
</requirements>
```

Read more about configuring Galaxy to run Docker jobs
[here](https://galaxyproject.org/admin/tools/docker/).



### Attributes

Attribute | Details | Required
--- | --- | ---
``type`` | This value describes the type of container that the tool may be executed in and currently may be ``docker`` or ``singularity``. | True


## ``tool`` > ``required_files``


This declaration is used to define files that must be shipped from the tool directory
for the tool to function properly in remote environments where the tool directory
is not available to the job.

All includes should be list before excludes. By default, the exclude list includes
the tool-data/**, test-data/**, and .hg/** glob patterns.

Pulsar hacks to implicitly find referenced files from the tool directory will be disabled
when this block is used. A future Galaxy tool profile version may disable these hacks
altogether and specifying this block for all referenced files should be considered a best
practice.



### Attributes

Attribute | Details | Required
--- | --- | ---
``extend_default_excludes`` | Set this to `false` to override the default excludes for mercurial, reference, and test data. | False


## ``tool`` > ``required_files`` > ``include``

Describe files to include when relocating tool directory for remote execution.


### Attributes

Attribute | Details | Required
--- | --- | ---
``type`` | Type of file reference `path` is. | False
``path`` | Path to referenced files - this should be relative to the tool's directory (this is the file the tool is located in not the repository directory if these conflict). | False


## ``tool`` > ``required_files`` > ``exclude``

Describe files to exclude when relocating tool directory for remote execution.


### Attributes

Attribute | Details | Required
--- | --- | ---
``type`` | Type of file reference `path` is. | False
``path`` | Path to referenced files - this should be relative to the tool's directory (this is the file the tool is located in not the repository directory if these conflict). | False


## ``tool`` > ``code``


*Deprecated*. Do not use this unless absolutely necessary.

The extensions described here can cause problems using your tool with certain components
of Galaxy (like the workflow system). It is highly recommended to avoid these constructs
unless absolutely necessary.

This tag set provides detailed control of the way the tool is executed. This
(optional) code can be deployed in a separate file in the same directory as the
tool's config file. These hooks are being replaced by new tool config features
and methods in the [/lib/galaxy/tools/\__init__.py](https://github.com/galaxyproject/galaxy/blob/dev/lib/galaxy/tools/__init__.py) code file.

### Examples

#### Dynamic Options

Use associated dynamic select lists where selecting an option in the first
select list dynamically re-renders the options in the second select list. In
this example, we are populating both dynamic select lists from metadata elements
associated with a tool's single input dataset. The 2 metadata elements we're
using look like this.

```python
MetadataElement(name="field_names", default=[], desc="Field names", readonly=True, optional=True, visible=True, no_value=[])
# The keys in the field_components map to the list of field_names in the above element
# which ensures order for select list options that are built from it.
MetadataElement(name="field_components", default={}, desc="Field names and components", readonly=True, optional=True, visible=True, no_value={})
```

Our tool config includes a code file tag like this.

```xml
<code file="tool_form_utils.py" />
```

Here are the relevant input parameters in our tool config. The first parameter
is the input dataset that includes the above metadata elements.

```xml
<param name="input" type="data" format="vtkascii,vtkbinary" label="Shape with uncolored surface field">
    <validator type="expression" message="Shape must have an uncolored surface field.">value is not None and len(value.metadata.field_names) > 0</validator>
</param>
```

The following parameter dynamically renders a select list consisting of the
elements in the ``field_names`` metadata element associated with the selected
input dataset.

```xml
<param name="field_name" type="select" label="Field name" refresh_on_change="true">
    <options>
        <filter type="data_meta" ref="input" key="field_names"/>
    </options>
    <validator type="no_options" message="The selected shape has no uncolored surface fields." />
</param>
```

The following parameter calls the ``get_field_components_options()`` function in
the ``tool_form_utils.py`` code file discussed above. This function returns the
value of the input dataset's ``field_components`` metadata element dictionary
whose key is the currently selected ``field_name`` from the select list parameter
above.

```xml
<param name="field_component_index" type="select" label="Field component index" dynamic_options="get_field_components_options(input, field_name=field_name)" help="Color will be applied to the selected field's component associated with this index." />
```

Changing the selected option in the ``field_name`` select list will dynamically
re-render the options available in the associated ``field_component_index`` select
list, which is the behavior we want.

The ``get_field_components_options()`` method looks like this.

```python
def get_field_components_options(dataset, field_name):
    options = []
    if dataset.metadata is None:
        return options
    if not hasattr(dataset.metadata, 'field_names'):
        return options
    if dataset.metadata.field_names is None:
        return options
    if field_name is None:
        # The expression validator that helps populate the select list of input
        # datsets in the icqsol_color_surface_field tool does not filter out
        # datasets with no field field_names, so we need this check.
        if len(dataset.metadata.field_names) == 0:
            return options
        field_name = dataset.metadata.field_names[0]
    field_components = dataset.metadata.field_components.get(field_name, [])
    for i, field_component in enumerate(field_components):
        options.append((field_component, field_component, i == 0))
    return options
```

#### Parameter Validation

This function is called before the tool is executed. If it raises any exceptions the tool execution will be aborted and the exception's value will be displayed in an error message box. Here is an example:

```python
def validate(incoming):
    """Validator for the plotting program"""


    bins = incoming.get("bins","")
    col = incoming.get("col","")


    if not bins or not col:
        raise Exception, "You need to specify a number for bins and columns"


    try:
        bins = int(bins)
        col = int(col)
    except:
        raise Exception, "Parameters are not integers, columns:%s, bins:%s" % (col, bins)


    if not 1<bins<100:
        raise Exception, "The number of bins %s must be a number between 1 and 100" % bins
```

This code will intercept a number of parameter errors and return corresponding error messages. The parameter ``incoming`` contains a dictionary with all the parameters that were sent through the web.

#### Pre-job and pre-process code

The signature of both of these is the same:

```python
def exec_before_job(inp_data, out_data, param_dict, tool):
def exec_before_process(inp_data, out_data, param_dict, tool):
```

The ``param_dict`` is a dictionary that contains all the values in the ``incoming`` parameter above plus a number of keys and values generated internally by galaxy. The ``inp_data`` and the ``out_data`` are dictionaries keyed by parameter name containing the classes that represent the data.

Example:

```python
def exec_before_process(inp_data, out_data, param_dict, tool):
    for name, data in out_data.items():
        data.name = 'New name'
```

This custom code will change the name of the data that was created for this tool to **New name**. The difference between these two functions is that the ``exec_before_job`` executes before the page returns and the user will see the new name right away. If one were to use ``exec_before_process`` the new name would be set only once the job starts to execute.

#### Post-process code

This code executes after the background process running the tool finishes its run. The example below is more advanced one that replaces the type of the output data depending on the parameter named ``extension``:

```python
from galaxy import datatypes
def exec_after_process(app, inp_data, out_data, param_dict, tool, stdout, stderr):
    ext = param_dict.get('extension', 'text')
    items = out_data.items()
    for name, data in items:
        newdata = datatypes.factory(ext)(id=data.id)
        for key, value in data. __dict__.items():
            setattr(newdata, key, value)
        newdata.ext = ext
        out_data[name] = newdata
```

The content of ``stdout`` and ``stderr`` are strings containing the output of the process.




### Attributes

Attribute | Details | Required
--- | --- | ---
``file`` | This value is the name of the executable code file, and is called in the ``exec_before_process()``, ``exec_before_job()``, ``exec_after_process()`` and ``exec_after_job()`` methods. | True


## ``tool`` > ``stdio``

Tools write the bulk of useful data to datasets, but they can also write messages to standard I/O (stdio) channels known as standard output (stdout) and standard error (stderr). Both stdout and stderr are typically written to the executing program's console or terminal. Previous versions of Galaxy checked stderr for execution errors - if any text showed up on stderr, then the tool's execution was marked as failed. However, many tools write messages to stderr that are not errors, and using stderr allows programs to redirect other interesting messages to a separate file. Programs may also exit with codes that indicate success or failure. One convention is for programs to return 0 on success and a non-zero exit code on failure.

Legacy tools (ones with ``profile`` unspecified or a ``profile`` of less than
16.04) will default to checking stderr for errors as described above. Newer
tools will instead treat an exit code other than 0 as an error. The
``detect_errors`` on ``command`` can swap between these behaviors but the
``stdio`` directive allows more options in defining error conditions (though
these aren't always intuitive).

With ``stdio`` directive, Galaxy can use regular expressions to scan stdout and
stderr, and it also allows exit codes to be scanned for ranges. The ``<stdio>``
tag has two subtags, ``<regex>`` and ``<exit_code>``, to define regular
expressions and exit code processing, respectively. They are defined below. If a
tool does not have any valid ``<regex>`` or ``<exit_code>`` tags, then Galaxy
will use the previous technique for finding errors.

A note should be made on the order in which exit codes and regular expressions
are applied and how the processing stops. Exit code rules are applied before
regular expression rules. The rationale is that exit codes are more clearly
defined and are easier to check computationally, so they are applied first. Exit
code rules are applied in the order in which they appear in the tool's
configuration file, and regular expressions are also applied in the order in
which they appear in the tool's configuration file. However, once a rule is
triggered that causes a fatal error, no further rules are
checked.



## ``tool`` > ``stdio`` > ``exit_code``


Tools may use exit codes to indicate specific execution errors. Many programs use 0 to indicate success and non-zero exit codes to indicate errors. Galaxy allows each tool to specify exit codes that indicate errors. Each ``<exit_code>`` tag defines a range of exit codes, and each range can be associated with a description of the error (e.g., "Out of Memory", "Invalid Sequence File") and an error level. The description just describes the condition and can be anything. The error level is either log, warning, fatal error, or fatal_oom. A warning means that stderr will be updated with the error's description. A fatal error means that the tool's execution will be marked as having an error and the workflow will stop. A fatal_oom indicates an out of memory condition and the job might be resubmitted if Galaxy is configured appropriately. Note that, if the error level is not supplied, then a fatal error is assumed to have occurred.

The exit code's range can be any consecutive group of integers. More advanced ranges, such as noncontiguous ranges, are currently not supported. Ranges can be specified in the form "m:n", where m is the start integer and n is the end integer. If ":n" is specified, then the exit code will be compared against all integers less than or equal to n. If "m:" is used, then the exit code will be compared against all integers greater than or equal to m. If the exit code matches, then the error level is applied and the error's description is added to stderr. If a tool's exit code does not match any of the supplied ``<exit_code>`` tags' ranges, then no errors are applied to the tool's execution.

Note that most Unix and Linux variants only support positive integers 0 to 255 for exit codes. If an exit code falls outside of this range, the usual convention is to only use the lower 8 bits for the exit code. The only known exception is if a job is broken into subtasks using the tasks runner and one of those tasks is stopped with a POSIX signal. (Note that signals should be used as a last resort for terminating processes.) In those cases, the task will receive -1 times the signal number. For example, suppose that a job uses the tasks runner and 8 tasks are created for the job. If one of the tasks hangs, then a sysadmin may choose to send the "kill" signal, SIGKILL, to the process. In that case, the task (and its job) will exit with an exit code of -9. More on POSIX signals can be found on [Wikipedia](https://en.wikipedia.org/wiki/Signal_(IPC)) as well as on the man page for "signal" (``man 7 signal``).

The ``<exit_code>`` tag's supported attributes are as follows:

* ``range``: This indicates the range of exit codes to check. The range can be one of the following:
  * ``n``: the exit code will only be compared to n;
  * ``[m:n]``: the exit code must be greater than or equal to m and less than or equal to n;
  * ``[m:]``: the exit code must be greater than or equal to m;
  * ``[:n]``: the exit code must be less than or equal to n.
* ``level``: This indicates the error level of the exit code. If no level is specified, then the fatal error level will be assumed to have occurred. The level can have one of following values:
  * ``log`` and ``warning``: If an exit code falls in the given range, then a description of the error will be added to the beginning of the source, prepended with either 'Log:' or 'Warning:'. A log-level/warning-level error will not cause the tool to fail.
  * ``fatal``: If an exit code falls in the given range, then a description of the error will be added to the beginning of stderr. A fatal-level error will cause the tool to fail.
  * ``fatal_oom``: If an exit code falls in the given range, then a description of the error will be added to the beginning of stderr. Depending on the job configuration, a fatal_oom-level error will cause the tool to be resubmitted or fail.
* ``description``: This is an optional description of the error that corresponds to the exit code.

The following is an example of the ``<exit_code>`` tag:

```xml
<stdio>
    <exit_code range="3:5" level="warning" description="Low disk space" />
    <exit_code range="6:" level="fatal" description="Bad input dataset" />
    <!-- Catching fatal_oom allows the job runner to potentially resubmit to a resource with more
         memory if Galaxy is configured to do this. -->
    <exit_code range="2" level="fatal_oom" description="Out of Memory" />
</stdio>
```

If the tool returns 0 or 1, then the tool will not be marked as having an error.
If the exit code is 2, then the tool will fail with the description ``Out of
Memory`` added to stderr. If the tool returns 3, 4, or 5, then the tool will not
be marked as having failed, but ``Low disk space`` will be added to stderr.
Finally, if the tool returns any number greater than or equal to 6, then the
description ``Bad input dataset`` will be added to stderr and the tool will be
marked as having failed.





## ``tool`` > ``stdio`` > ``regex``


A regular expression defines a pattern of characters. The patterns include the following:

* ``GCTA``, which matches on the fixed string "GCTA";
* ``[abcd]``, which matches on the characters a, b, c, or d;
* ``[CG]{12}``, which matches on 12 consecutive characters that are C or G;
* ``a.*z``, which matches on the character "a", followed by 0 or more characters of any type, followed by a "z";
* ``^X``, which matches the letter X at the beginning of a string;
* ``Y$``, which matches the letter Y at the end of a string.

There are many more possible regular expressions. A reference to all supported
regular expressions can be found under
[Python Regular Expression Syntax](https://docs.python.org/3/library/re.html#regular-expression-syntax).

A regular expression includes the following attributes:

* ``source``: This tells whether the regular expression should be matched against stdout, stderr, or both. If this attribute is missing or is incorrect, then both stdout and stderr will be checked. The source can be one of the following values:
  * ``stdout``: the regular expression will be applied to stdout;
  * ``stderr``: the regular expression will be applied to stderr;
  * ``both``: the regular expression will be applied to both stderr and stdout (which is the default case).
* ``match``: This is the regular expression that will be used to match against stdout and/or stderr. If the ``<regex>`` tag does not contain the match attribute, then the ``<regex>`` tag will be ignored. The regular expression can be any valid Python regular expression. All regular expressions are performed case insensitively. For example, if match contains the regular expression "actg", then the regular expression will match against "actg", "ACTG", "AcTg", and so on. Also note that, if double quotes (") are to be used in the match attribute, then the value " can be used in place of double quotes. Likewise, if single quotes (') are to be used in the match attribute, then the value ' can be used if necessary.
* ``level``: This works very similarly to the ``<exit_code>`` tag, except that, when a regular expression matches against its source, the description is added to the beginning of the source. For example, if stdout matches on a regular expression, then the regular expression's description is added to the beginning of stdout (instead of stderr). If no level is specified, then the fatal error level will be assumed to have occurred. The level can have one of following values:
  * ``log`` and ``warning``: If the regular expression matches against its source input (i.e., stdout and/or stderr), then a description of the error will be added to the beginning of the source, prepended with either 'Log:' or 'Warning:'. A log-level/warning-level error will not cause the tool to fail.
  * ``fatal``: If the regular expression matches against its source input, then a description of the error will be added to the beginning of the source. A fatal-level error will cause the tool to fail.
  * ``fatal_oom``: In contrast to fatal the job might be resubmitted if possible according to the job configuration.
* ``description``: Just like its ``exit_code`` counterpart, this is an optional description of the regular expression that has matched.

The following is an example of regular expressions that may be used:

```xml
<stdio>
    <regex match="low space"
           source="both"
           level="warning"
           description="Low space on device" />
    <regex match="error"
           source="stdout"
           level="fatal"
           description="Unknown error encountered" />
    <!-- Catching fatal_oom allows the job runner to potentially resubmit to a resource with more
         memory if Galaxy is configured to do this. -->
    <regex match="out of memory"
           source="stdout"
           level="fatal_oom"
           description="Out of memory error occurred" />
    <regex match="[CG]{12}"
           description="Fatal error - CG island 12 nts long found" />
    <regex match="^Branch A"
           level="warning"
           description="Branch A was taken in execution" />
</stdio>
```

The regular expression matching proceeds as follows. First, if either stdout or
stderr match on ``low space``, then a warning is registered. If stdout contained
the string ``---LOW SPACE---``, then stdout has the string ``Warning: Low space
on device`` added to its beginning. The same goes for if stderr had contained the
string ``low space``. Since only a warning could have occurred, the processing
continues.

Next, the regular expression ``error`` is matched only against stdout. If stdout
contains the string ``error`` regardless of its capitalization, then a fatal
error has occurred and the processing stops. In that case, stdout would be
prepended with the string ``Fatal: Unknown error encountered``. Note that, if
stderr contained ``error``, ``ERROR``, or ``ErRor`` then it would not matter -
stderr was not being scanned.

If the second regular expression does not match, the regular expression "out of memory"
is checked on stdout. If found, Galaxy tries to resubmit the job with more memory
if configured correctly, otherwise the job fails.

If the previous regular expressions does not match, then the fourth regular
expression is checked. The fourth regular expression does not contain an error
level, so an error level of ``fatal`` is assumed. The fourth regular expression
also does not contain a source, so both stdout and stderr are checked. The fourth
regular expression looks for 12 consecutive "C"s or "G"s in any order and in
uppercase or lowercase. If stdout contained ``cgccGGCCcGGcG`` or stderr
contained ``CCCCCCgggGGG``, then the regular expression would match, the tool
would be marked with a fatal error, and the stream that contained the
12-nucleotide CG island would be prepended with ``Fatal: Fatal error - CG island
12 nts long found``.

Finally, if the tool did not match any of the fatal errors, then the fifth
regular expression is checked. Since no source is specified, both stdout and
stderr are checked. If ``Branch A`` is at the beginning of stdout or stderr, then
a warning will be registered and the source that contained ``Branch A`` will be
prepended with the warning ``Warning: Branch A was taken in execution``.





## ``tool`` > ``version_command``

Specifies the command to be run in
order to get the tool's version string. The resulting value will be found in the
"Info" field of the history dataset.

Unlike the [command](#tool-command) tag, with the exception of the string
``$__tool_directory__`` this value is taken as a literal and so there is no
need to escape values like ``$`` and command inputs are not available for variable
substitution.

### Examples

A simple example for a [TopHat](https://ccb.jhu.edu/software/tophat/index.shtml)
tool definition might just be:

```xml
<version_command>tophat -version</version_command>
```

An example that leverages a Python script (e.g. ``count_reads.py``) shipped with
the tool might be:

```xml
<version_command>python '$__tool_directory__/count_reads.py'</version_command>
```

Examples are included in the test tools directory including:

- [version_command_plain.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/version_command_plain.xml)
- [version_command_tool_dir.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/version_command_tool_dir.xml)
- [version_command_interpreter.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/version_command_interpreter.xml) (*deprecated*)




### Attributes

Attribute | Details | Required
--- | --- | ---
``interpreter`` | *Deprecated*. This will prefix the version command with the value of this attribute (e.g. ``python`` or ``perl``) and the tool directory, in order to run an executable file shipped with the tool. It is recommended to instead use ``<interpreter> '$__tool_directory__/<executable_name>'`` in the tag content. If this attribute is not specified, the tag should contain a Bash command calling executable(s) available in the ``$PATH``, as modified after loading the requirements. | False


## ``tool`` > ``command``


This tag specifies how Galaxy should invoke the tool's executable, passing its
required input parameter values (the command line specification links the
parameters supplied in the form with the actual tool executable). Any word
inside it starting with a dollar sign (``$``) will be treated as a variable whose
values can be acquired from one of three sources: parameters, metadata, or
output files. After the substitution of variables with their values, the content
is interpreted with [Cheetah](https://pythonhosted.org/Cheetah/) and finally given
to the interpreter specified in the corresponding attribute (if any).

### Examples

The following uses a compiled executable ([bedtools](https://bedtools.readthedocs.io/en/latest/)).

```xml
<command><![CDATA[
bed12ToBed6 -i '$input' > '$output'
]]></command>
```

A few things to note about even this simple example:

* Input and output variables (boringly named ``input`` and ``output``)
  are expanded into paths using the ``$`` Cheetah directive.
* Paths should be quoted so that the Galaxy database files may contain spaces.
* We are building up a shell script - so special characters like ``>`` can be used
  (in this case the standard output of the bedtools call is written to the path
  specified by ``'$output'``).

The bed12ToBed6 tool can be found [here](https://github.com/galaxyproject/tools-iuc/blob/master/tools/bedtools/bed12ToBed6.xml).

A more sophisticated bedtools example demonstrates the use of loops, conditionals,
and uses whitespace to make a complex command very readable can be found in
[annotateBed](https://github.com/galaxyproject/tools-iuc/blob/master/tools/bedtools/annotateBed.xml)
tool.

```xml
<command><![CDATA[
bedtools annotate
-i '${inputA}'
#if $names.names_select == 'yes':
    -files
    #for $bed in $names.beds:
        '${bed.input}'
    #end for
    -names
    #for $bed in $names.beds:
        '${bed.inputName}'
    #end for
#else:
    #set files = '" "'.join([str($file) for $file in $names.beds])
    -files '${files}'
    #set names = '" "'.join([str($name.display_name) for $name in $names.beds])
    -names '${names}'
#end if
$strand
$counts
$both
> '${output}'
]]></command>
```

The following example (taken from [xpath](https://github.com/galaxyproject/tools-iuc/blob/master/tools/xpath/xpath.xml) tool)
uses an interpreted executable. In this case a Perl script is shipped with the
tool and the directory of the tool itself is referenced with ``$__tool_directory__``.

```xml
<command><![CDATA[
perl '$__tool_directory__/xpath' -q -e '$expression' '$input' > '$output'
]]></command>
```

The following example demonstrates accessing metadata from datasets. Metadata values
(e.g., ``${input.metadata.chromCol}``) are acquired from the ``Metadata`` model associated
with the objects selected as the values of each of the relative form field
parameters in the tool form. Accessing this information is generally enabled using
the following feature components.

A set of "metadata information" is defined for each supported data type (see the
``MetadataElement`` objects in the various data types classes in
[/lib/galaxy/datatypes](https://github.com/galaxyproject/galaxy/tree/dev/lib/galaxy/datatypes).
The ``DatasetFilenameWrapper`` class in the
[/lib/galaxy/tools/wrappers.py](https://github.com/galaxyproject/galaxy/blob/dev/lib/galaxy/tools/wrappers.py)
code file wraps a metadata collection to return metadata parameters wrapped
according to the Metadata spec.

```xml
<command><![CDATA[
        #set genome = $input.metadata.dbkey
        #set datatype = $input.datatype
        mkdir -p output_dir &&
        python '$__tool_directory__/extract_genomic_dna.py'
        --input '$input'
        --genome '$genome'
        #if $input.is_of_type("gff"):
            --input_format "gff"
            --columns "1,4,5,7"
            --interpret_features $interpret_features
        #else:
            --input_format "interval"
            --columns "${input.metadata.chromCol},${input.metadata.startCol},${input.metadata.endCol},${input.metadata.strandCol},${input.metadata.nameCol}"
        #end if
        --reference_genome_source $reference_genome_cond.reference_genome_source
        #if str($reference_genome_cond.reference_genome_source) == "cached"
            --reference_genome $reference_genome_cond.reference_genome.fields.path
        #else:
            --reference_genome $reference_genome_cond.reference_genome
        #end if
        --output_format $output_format_cond.output_format
        #if str($output_format_cond.output_format) == "fasta":
            --fasta_header_type $output_format_cond.fasta_header_type_cond.fasta_header_type
            #if str($output_format_cond.fasta_header_type_cond.fasta_header_type) == "char_delimited":
                --fasta_header_delimiter $output_format_cond.fasta_header_type_cond.fasta_header_delimiter
            #end if
        #end if
        --output '$output'
]]></command>
```

In additon to demonstrating accessing metadata, this example demonstrates:

* ``$input.is_of_type("gff")`` which can be used to check if an input is of a
  given datatype.
* ``#set datatype = $input.datatype`` which is the syntax for defining variables
  in Cheetah.

### Reserved Variables

Galaxy provides a few pre-defined variables which can be used in your command line,
even though they don't appear in your tool's parameters.

Name | Description
---- | -----------
``$__tool_directory__`` | The directory the tool description (XML file) currently resides in (new in 15.03)
``$__new_file_path__`` | ``config/galaxy.ini``'s ``new_file_path`` value
``$__tool_data_path__`` | ``config/galaxy.ini``'s tool_data_path value
``$__root_dir__`` | Top-level Galaxy source directory made absolute via ``os.path.abspath()``
``$__datatypes_config__`` | ``config/galaxy.ini``'s datatypes_config value
``$__user_id__`` | Email's numeric ID (id column of ``galaxy_user`` table in the database)
``$__user_email__`` | User's email address
``$__app__`` | The ``galaxy.app.UniverseApplication`` instance, gives access to all other configuration file variables (e.g. $__app__.config.output_size_limit). Should be used as a last resort, may go away in future releases.
``$__target_datatype__`` | Only available in converter tools when run internally by Galaxy. Contains the target datatype of the conversion

Additional runtime properties are available as environment variables. Since these
are not Cheetah variables (the values aren't available until runtime) these should likely
be escaped with a backslash (``\``) when appearing in ``command`` or ``configfile`` elements.

For internal converter tools using ``$__target_datatype__`` it is recommended to add a select
input parameter with name ``__target_datatype__`` in order to make the tool testable, see
for instance the [biom converter](https://github.com/galaxyproject/galaxy/blob/master/lib/galaxy/datatypes/converters/biom.xml).

Name | Description
---- | -----------
``\${GALAXY_SLOTS:-4}`` | Number of cores/threads allocated by the job runner or resource manager to the tool for the given job (here 4 is the default number of threads to use if running via custom runner that does not configure GALAXY_SLOTS or in an older Galaxy runtime).
``\$GALAXY_MEMORY_MB`` | Total amount of memory in megabytes (1024^2 bytes) allocated by the administrator (via the resource manager) to the tool for the given job. If unset, tools should not attempt to limit memory usage.
``\$GALAXY_MEMORY_MB_PER_SLOT`` | Amount of memory per slot in megabytes (1024^2 bytes) allocated by the administrator (via the resource manager) to the tool for the given job. If unset, tools should not attempt to limit memory usage.
``\$_GALAXY_JOB_TMP_DIR`` | Path to an empty directory in the job's working directory that can be used as a temporary directory.

See the [Planemo docs](https://planemo.readthedocs.io/en/latest/writing_advanced.html#cluster-usage)
on the topic of ``GALAXY_SLOTS`` for more information and examples.

### Error detection

The ``detect_errors`` attribute of ``command``, if present, loads a preset of error detection checks (for exit codes and content of stdio to indicate fatal tool errors or fatal out of memory errors). It can be one of:

* ``default``: for non-legacy tools with absent stdio block non-zero exit codes are added. For legacy tools or if a stdio block is present nothing is added.
* ``exit_code``: adds checks for non zero exit codes (The @jmchilton recommendation). The ``oom_exit_code`` parameter can be used to add an additional out of memory indicating exit code.
* ``aggressive``: adds checks for non zero exit codes, and checks for ``Exception:``, ``Error:`` in the standard error. Additionally checks for messages in the standard error that indicate an out of memory error (``MemoryError``, ``std::bad_alloc``, ``java.lang.OutOfMemoryError``, ``Out of memory``). (The @bgruening recommendation).

Prior to Galaxy release 19.01 the stdio block has only been used for non-legacy tools using ``default``. From release 19.01 checks defined in the stdio tag are prepended to the checks defined by the presets loaded in the command block.


### Best Practices

Find the Intergalactic Utilities Commision suggested best practices for this
element [here](https://planemo.readthedocs.io/en/latest/standards/docs/best_practices/tool_xml.html#command-tag).


### Attributes

Attribute | Details | Required
--- | --- | ---
``detect_errors`` | The ``detect_errors`` attribute of ``command``, if present, loads a preset of error detection checks (for exit codes and content of stdio to indicate fatal tool errors or fatal out of memory errors). It can be one of:  * ``default``: for non-legacy tools with absent stdio block non-zero exit codes are added. For legacy tools or if a stdio block is present nothing is added. * ``exit_code``: adds checks for non zero exit codes. The ``oom_exit_code`` parameter can be used to add an additional out of memory indicating exit code. This is the default when a tool specifies a ``profile`` >= 16.04. * ``aggressive``: adds checks for non zero exit codes, and checks for ``Exception:``, ``Error:`` in the standard error. Additionally checks for messages in the standard error that indicate an out of memory error (``MemoryError``, ``std::bad_alloc``, ``java.lang.OutOfMemoryError``, ``Out of memory``). | False
``oom_exit_code`` | Only used if ``detect_errors="exit_code"``, tells Galaxy the specified exit code indicates an out of memory error. Galaxy instances may be configured to retry such jobs on resources with more memory. | False
``use_shared_home`` | When running a job for this tool, do not isolate its ``$HOME`` directory within the job's directory - use either the ``shared_home_dir`` setting in Galaxy or the default ``$HOME`` specified in the job's default environment. | False
``interpreter`` | *Deprecated*. This will prefix the command with the value of this attribute (e.g. ``python`` or ``perl``) and the tool directory, in order to run an executable file shipped with the tool. It is recommended to instead use ``<interpreter> '$__tool_directory__/<executable_name>'`` in the tag content. If this attribute is not specified, the tag should contain a Bash command calling executable(s) available in the ``$PATH``, as modified after loading the requirements. | False
``strict`` | This boolean forces the ``#set -e`` directive on in shell scripts - so that in a multi-part command if any part fails the job exits with a non-zero exit code. This is enabled by default for tools with ``profile>=20.09`` and disabled on legacy tools. | False


## ``tool`` > ``environment_variables``


This directive should contain one or more ``environment_variable`` definition.
      



## ``tool`` > ``environment_variables`` > ``environment_variable``



This directive defines an environment variable that will be available when the
tool executes. The body should be a Cheetah template block that may reference
the tool's inputs as demonstrated below.

### Example

The following demonstrates a couple ``environment_variable`` definitions.

```xml
<environment_variables>
    <environment_variable name="INTVAR">$inttest</environment_variable>
    <environment_variable name="IFTEST">#if int($inttest) == 3
ISTHREE
#else#
NOTTHREE
#end if#</environment_variable>
    </environment_variables>
</environment_variables>
```

If these environment variables are used in another Cheetah context, such as in
the ``command`` block, the ``$`` used indicate shell expansion of a variable
should be escaped with a ``\`` so prevent it from being evaluated as a Cheetah
variable instead of shell variable.

```xml
<command>
    echo "\$INTVAR"  >  $out_file1;
    echo "\$IFTEST"  >> $out_file1;
</command>
```

### inject

The Galaxy user's API key can be injected into an environment variable by setting ``inject``
attribute to ``api_key`` (e.g. ``inject="api_key"``).

```xml
<environment_variables>
    <environment_variable name="GALAXY_API_KEY" inject="api_key" />
</environment_variables>
```

The framework allows setting this via environment variable and not via templating variables
in order to discourage setting the actual values of these keys as command line arguments.
On shared systems this provides some security by preventing a simple process listing command
from exposing keys.



### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | Name of the environment variable to define. | False
``inject`` | Special variable to inject into the environment variable. Currently 'api_key' is the only option and will cause the user's API key to be injected via this environment variable. | False
``strip`` | Whether to strip leading and trailing whitespace from the calculated value before exporting the environment variable. | False


## ``tool`` > ``configfiles``

See
[xy_plot.xml](https://github.com/galaxyproject/tools-devteam/blob/master/tools/xy_plot/xy_plot.xml)
for an example of how this tag set is used in a tool. This tag set is a
container for ``<configfile>`` and ``<inputs>`` tag sets - which can be used
to setup configuration files for use by tools.



## ``tool`` > ``configfiles`` > ``configfile``



This tag set is contained within the ``<configfiles>`` tag set. It allows for
the creation of a temporary file for file-based parameter transfer.

*Example*

The following is taken from the [xy_plot.xml](https://github.com/galaxyproject/tools-devteam/blob/master/tools/xy_plot/xy_plot.xml)
tool config.

```xml
<configfiles>
    <configfile name="script_file">
      ## Setup R error handling to go to stderr
      options(show.error.messages=F, error = function () { cat(geterrmessage(), file=stderr()); q("no", 1, F) })
      ## Determine range of all series in the plot
      xrange = c(NULL, NULL)
      yrange = c(NULL, NULL)
      #for $i, $s in enumerate($series)
          s${i} = read.table("${s.input.file_name}")
          x${i} = s${i}[,${s.xcol}]
          y${i} = s${i}[,${s.ycol}]
          xrange = range(x${i}, xrange)
          yrange = range(y${i}, yrange)
      #end for
      ## Open output PDF file
      pdf("${out_file1}")
      ## Dummy plot for axis / labels
      plot(NULL, type="n", xlim=xrange, ylim=yrange, main="${main}", xlab="${xlab}", ylab="${ylab}")
      ## Plot each series
      #for $i, $s in enumerate($series)
          #if $s.series_type['type'] == "line"
              lines(x${i}, y${i}, lty=${s.series_type.lty}, lwd=${s.series_type.lwd}, col=${s.series_type.col})
          #elif $s.series_type.type == "points"
              points(x${i}, y${i}, pch=${s.series_type.pch}, cex=${s.series_type.cex}, col=${s.series_type.col})
          #end if
      #end for
      ## Close the PDF file
      devname = dev.off()
    </configfile>
</configfiles>
```

This file is then used in the ``command`` block of the tool as follows:

```xml
<command>bash '$__tool_directory__/r_wrapper.sh' '$script_file'</command>
```




### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | Cheetah variable used to reference the path to the file created with this directive. | False
``filename`` | Path relative to the working directory of the tool for the configfile created in response to this directive. | False


## ``tool`` > ``configfiles`` > ``inputs``



This tag set is contained within the ``<configfiles>`` tag set. It tells Galaxy to
write out a JSON representation of the tool parameters.

*Example*

The following will create a Cheetah variable that can be evaluated as ``$inputs`` that
will contain the tool parameter inputs.

```xml
<configfiles>
    <inputs name="inputs" />
<configfiles>
```

The following will instead write the inputs to the tool's working directory with
the specified name (i.e. ``inputs.json``).

```xml
<configfiles>
    <inputs name="inputs" filename="inputs.json" />
<configfiles>
```

A contrived example of a tool that uses this is the test tool
[inputs_as_json.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/inputs_as_json.xml).

By default this file will not contain paths for data or collection inputs. To include simple
paths for data or collection inputs set the ``data_style`` attribute to ``paths`` (see [inputs_as_json_with_paths.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/inputs_as_json_with_paths.xml) for an example).
To include a dictionary with staging paths, paths and metadata files set the ``data_style`` attribute to ``staging_path_and_source_path``.
An example tool that uses ``staging_path_and_source_path`` is [inputs_as_json_with_staging_path_and_source_path.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/inputs_as_json_with_staging_path_and_source_path.xml)

For tools with profile >= 20.05 a select with ``multiple="true"`` is rendered as an array which is empty if nothing is selected. For older profile versions select lists are rendered as comma separated strings or a literal ``null`` in case nothing is selected.



### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | Cheetah variable to populate the path to the inputs JSON file created in response to this directive. | False
``filename`` | Path relative to the working directory of the tool for the inputs JSON file created in response to this directive. | False
``data_style`` | Set to 'paths' to include dataset paths in the resulting file. Set to 'staging_path_and_source_path' to include a staging path, a source path and all metadata files. | False


## ``tool`` > ``inputs``

Consists of all elements that define the
tool's input parameters. Each [param](#tool-inputs-param) element contained in this element
can be used as a command line parameter within the [command](#tool-command) text content. Most
tools will not need to specify any attributes on this tag itself.



### Attributes

Attribute | Details | Required
--- | --- | ---
``action`` | URL used by data source tools. | False
``check_values`` | Set to ``false`` to disable parameter checking in data source tools. | False
``method`` | Data source HTTP action (e.g. ``get`` or ``put``) to use. | False
``target`` | UI link target to use for data source tools (e.g. ``_top``). | False
``nginx_upload`` | This boolean indicates if this is an upload tool or not. | False


## ``tool`` > ``inputs`` > ``section``


This tag is used to group parameters into sections of the interface. Sections
are implemented to replace the commonly used tactic of hiding advanced options
behind a conditional, with sections you can easily visually group a related set
of options.

### Example

The XML configuration is relatively trivial for sections:

```xml
<inputs>
    <section name="section_name" title="Section Title" >
        <param name="parameter_name" type="text" label="A parameter  label" />
    </section>
</inputs>
```

In your command template, you'll need to include the section name to access the
variable:

```
$section_name.parameter_name
```

In output filters sections are represented as dictionary with the same name as the section:

```
<filter>section_name['parameter_name']</filter>
```

In order to reference parameters in sections from tags in the `<outputs>` section, e.g. in the `format_source` attribute of `<data>` tags, the syntax is currently:

```
<data name="output" format_source="parameter_name" metadata_source="parameter_name"/>
```

Note that references to other parameters in the `<inputs>` section are only possible if the reference is in the same section or its parents (and is defined earlier), therefore only `parameter_name` is used.

```
    <param name="foo" type="data" format="tabular"/>
    <param name="bar" type="data_column" data_ref="foo"/>
    <section>
        <param name="qux" type="data_column" data_ref="foo"/>
        <param name="foo" type="data" format="tabular"/>
        <param name="baz" type="data_column" data_ref="foo"/>
    </section>
```

In the above example `bar` and `qux` will refer to the first foo outside of the section and `baz` to the `foo` inside the section. This illustrates why non-unique parameter names are strongly discouraged. 

The following will not work:

```
    <section>
        <param name="foo" type="data" format="tabular"/>
    </section>
    <param name="bar" type="data_column" data_ref="foo"/>
```

Further examples can be found in the [test case](https://github.com/galaxyproject/galaxy/blob/master/test/functional/tools/section.xml) from [pull request #35](https://github.com/galaxyproject/galaxy/pull/35).



### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | The internal key used for the section. | True
``title`` | Human readable label for the section. | True
``expanded`` | Whether the section should be expanded by default or not. If not, the default set values are used. | False
``help`` | Short help description for section, rendered just below the section. | False


## ``tool`` > ``inputs`` > ``repeat``


See
[xy_plot.xml](https://github.com/galaxyproject/tools-devteam/blob/master/tools/xy_plot/xy_plot.xml)
for an example of how to use this tag set. This is a container for any tag sets
that can be contained within the ``<inputs>`` tag set. When this is used, the
tool will allow the user to add any number of additional sets of the contained
parameters (an option to add new iterations will be displayed on the tool form).
All input parameters contained within the ``<repeat>`` tag can be retrieved by
enumerating over ``$<name_of_repeat_tag_set>`` in the relevant Cheetah code.
This returns the rank and the parameter objects of the repeat container. See the
Cheetah code below.

### Example

This part is contained in the ``<inputs>`` tag set.

```xml
<repeat name="series" title="Series">
    <param name="input" type="data" format="tabular" label="Dataset"/>
    <param name="xcol" type="data_column" data_ref="input" label="Column for x axis"/>
    <param name="ycol" type="data_column" data_ref="input" label="Column for y axis"/>
</repeat>
```

This Cheetah code can be used in the ``<command>`` tag set or the
``<configfile>`` tag set.

```
#for $i, $s in enumerate($series)
    rank_of_series=$i
    input_path='${s.input}'
    x_colom=${s.xcol}
    y_colom=${s.ycol}
#end for
```

### Testing

This is an example test case with multiple repeat elements for the example above.

```xml
<test>
    <repeat name="series">
        <param name="input" value="tabular1.tsv" ftype="tabular"/>
        <param name="xcol" value="1"/>
        <param name="ycol" value="2"/>
    </repeat>
    <repeat name="series">
        <param name="input" value="tabular2.tsv" ftype="tabular"/>
        <param name="xcol" value="4"/>
        <param name="ycol" value="2"/>
    </repeat>
    <output name="out_file1" file="cool.pdf" ftype="pdf" />
</test>
```

See the documentation on the [repeat test directive](#tool-tests-test-repeat).

An older way to specify repeats in a test is by instances that are created by referring to names with a special format: ``<repeat name>_<repeat index>|<param name>``

```xml
<test>
    <param name="series_0|input" value="tabular1.tsv" ftype="tabular"/>
    <param name="series_0|xcol" value="1"/>
    <param name="series_0|ycol" value="2"/>
    <param name="series_1|input" value="tabular2.tsv" ftype="tabular"/>
    <param name="series_1|xcol" value="4"/>
    <param name="series_1|ycol" value="2"/>
    <output name="out_file1" file="cool.pdf" ftype="pdf" />
</test>
```

The test tool [disambiguate_repeats.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/disambiguate_repeats.xml)
demonstrates both testing strategies.




### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | Name for this element | False
``title`` | The title of the repeat section, which will be displayed on the tool form. | True
``min`` | The minimum number of repeat units. | False
``max`` | The maximum number of repeat units. | False
``default`` | The default number of repeat units. | False
``help`` | Short help description for repeat element. | False


## ``tool`` > ``inputs`` > ``conditional``



This is a container for conditional parameters in the tool (must contain 'when'
tag sets) - the command line (or portions thereof) are then wrapped in an if-else
statement. A good example tool that demonstrates many conditional parameters is
[biom_convert.xml](https://github.com/galaxyproject/tools-iuc/blob/master/tools/biom_format/biom_convert.xml).

```xml
<conditional name="input_type">
    <param name="input_type_selector" type="select" label="Choose the source BIOM format">
        <option value="tsv" selected="true">Tabular File</option>
        <option value="biom">BIOM File</option>
    </param>
    <when value="tsv">
        <param name="input_table" type="data" format="tabular" label="Tabular File" argument="--input-fp"/>
        <param argument="--process-obs-metadata" type="select" label="Process metadata associated with observations when converting">
            <option value="" selected="true">Do Not process metadata</option>
            <option value="taxonomy">taxonomy</option>
            <option value="naive">naive</option>
            <option value="sc_separated">sc_separated</option>
        </param>
    </when>
    <when value="biom">
        <param name="input_table" type="data" format="biom1" label="Tabular File" argument="--input-fp"/>
    </when>
</conditional>
```

The first directive following the conditional is a [param](#tool-inputs-param),
this param must be of type ``select`` or ``boolean``. Depending on the value a
user selects for this "test" parameter - different UI elements will be shown.
These different paths are described by the following the ``when`` blocks shown
above.

The following Cheetah block demonstrates the use of the ``conditional``
shown above:

```
biom convert -i "${input_type.input_table}" -o "${output_table}"
#if str($input_type.input_type_selector) == "tsv":
    #if $input_type.process_obs_metadata:
        --process-obs-metadata "${input_type.process_obs_metadata}"
    #end if
#end if
```

Notice that the parameter ``input_table`` appears down both ``when`` clauses
so ``${input_type.input_table}`` appears unconditionally but we need to
conditionally reference ``${input_type.process_obs_metadata}`` with a Cheetah
``if`` statement.

A common use of the conditional wrapper is to select between reference data
managed by the Galaxy admins (for instance via
[data managers](https://galaxyproject.org/admin/tools/data-managers/)
) and
history files. A good example tool that demonstrates this is
the [Bowtie 2](https://github.com/galaxyproject/tools-iuc/blob/master/tools/bowtie2/bowtie2_wrapper.xml) wrapper.

```xml
<conditional name="reference_genome">
  <param name="source" type="select" label="Will you select a reference genome from your history or use a built-in index?" help="Built-ins were indexed using default options. See `Indexes` section of help below">
    <option value="indexed">Use a built-in genome index</option>
    <option value="history">Use a genome from the history and build index</option>
  </param>
  <when value="indexed">
    <param name="index" type="select" label="Select reference genome" help="If your genome of interest is not listed, contact the Galaxy team">
      <options from_data_table="bowtie2_indexes">
        <filter type="sort_by" column="2"/>
      </options>
      <validator type="no_options" message="No indexes are available for the selected input dataset"/>
    </param>
  </when>
  <when value="history">
    <param name="own_file" type="data" format="fasta" label="Select reference genome" />
  </when>
</conditional>
```

The Bowtie 2 wrapper also demonstrates other conditional paths - such as choosing
between paired inputs of single stranded inputs.



### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | Name for this element | False
``value_from`` | Infrequently used option to dynamically access Galaxy internals, this should be avoided.  Galaxy method to execute. | False
``value_ref`` | Infrequently used option to dynamically access Galaxy internals, this should be avoided.  Referenced parameter to pass method. | False
``value_ref_in_group`` | Infrequently used option to dynamically access Galaxy internals, this should be avoided.  Is referenced parameter is the same group. | False
``label`` | Human readable description for the conditional, unused in the Galaxy UI currently. | False


## ``tool`` > ``inputs`` > ``conditional`` > ``when``

This directive describes one potential
set of input for the tool at this depth. See documentation for the
[conditional](#tool-inputs-conditional) block for more details and examples (XML
and corresponding Cheetah conditionals).


### Attributes

Attribute | Details | Required
--- | --- | ---
``value`` | Value for the tool form test parameter corresponding to this ``when`` block. | True


## ``tool`` > ``inputs`` > ``param``



Contained within the ``<inputs>`` tag set - each of these specifies a field that
will be displayed on the tool form. Ultimately, the values of these form fields
will be passed as the command line parameters to the tool's executable.

### Common Attributes

The attributes valid for this tag vary wildly based on the ``type`` of the
parameter being described. All the attributes for the ``param`` element are
documented below for completeness, but here are the common ones for each
type are as follows:




#### Attributes

Attribute | Details | Required
--- | --- | ---
``type`` | Describes the parameter type - each different type as different semantics and the tool form widget is different. Currently valid parameter types are: ``text``,  ``integer``,  ``float``,  ``boolean``,  ``genomebuild``,  ``select``, ``color``,  ``data_column``,  ``hidden``,  ``hidden_data``,  ``baseurl``, ``file``,  ``ftpfile``,  ``data``,  ``data_collection``,  ``library_data``, ``drill_down``. The definition of supported parameter types as defined in the ``parameter_types`` dictionary in [/lib/galaxy/tools/parameters/basic.py](https://github.com/galaxyproject/galaxy/blob/master/lib/galaxy/tools/parameters/basic.py). | True
``name`` | Name for this element. This ``name`` is used as the Cheetah variable containing the user-supplied parameter name in ``command`` and ``configfile`` elements. The name should not contain pipes or periods (e.g. ``.``). Some "reserved" names are ``REDIRECT_URL``, ``DATA_URL``, ``GALAXY_URL``. | False
``argument`` | If the parameter reflects just one command line argument of a certain tool, this tag should be set to that particular argument. It is rendered in parenthesis after the help section, and it will create the name attribute (if not given explicitly) from the argument attribute by stripping leading dashes and replacing all remaining dashes by underscores (e.g. if ``argument="--long-parameter"`` then ``name="long_parameter"`` is implicit). | False
``label`` | The attribute value will be displayed on the tool page as the label of the form field (``label="Sort Query"``). | False
``help`` | Short bit of text, rendered on the tool form just below the associated field to provide information about the field. Find the Intergalactic Utilities Commision suggested best practices for this element [here](https://planemo.readthedocs.io/en/latest/standards/docs/best_practices/tool_xml.html#parameter-help). | False
``optional`` | If ``false``, parameter must have a value. Defaults to ``false`` except when the ``type`` attribute value is ``select`` and ``multiple`` is ``true``. | False
``refresh_on_change`` | Force a reload of the tool panel when the value of this parameter changes to allow ``code`` file processing. See deprecation-like notice for ``code`` blocks. | False


### Parameter Types

#### ``text``

When ``type="text"``, the parameter is free form text and appears as a text box
in the tool form.

##### Examples

Sometimes you need labels for data or graph axes, chart titles, etc. This can be
done using a text field. The following will create a text box with the default
value of "V1".

```xml
<param name="xlab" type="text" value="V1" label="Label for x axis" />
```

The ``area`` boolean attribute can be used to change the ``text`` parameter to a
two-dimensional text area instead of a single line text box.

```xml
<param name="foo" type="text" area="true" />
```

Since release 17.01, ``text`` parameters can also supply a static list of preset
defaults options. The user **may** be presented with the option to select one of
these but will be allowed to supply an arbitrary text value.

```xml
<param name="foo" type="text" value="foo 1">
    <option value="foo 1">Foo 1 Display</option>
    <option value="foo 2">Foo 2 Display</option>
</param>
```

See [param_text_option.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/param_text_option.xml)
for a demonstration of this.




##### Attributes

Attribute | Details | Required
--- | --- | ---
``area`` | Boolean indicating if this should be rendered as a one line text box (if ``false``, the default) or a multi-line text  area (if ``true``). Used only when the ``type`` attribute value is ``text``. | False
``value`` | The default value for this parameter. | False
``size`` | *Deprecated*. Completely ignored since release 16.10. Used only when the ``type`` attribute value is ``text``. | False


#### ``integer`` and ``float``

These parameters represent whole number and real numbers, respectively.

##### Example

```xml
<param name="region_size" type="integer" value="1" label="Size of the flanking regions" />
```




##### Attributes

Attribute | Details | Required
--- | --- | ---
``value`` | The default value for this parameter. | False
``min`` | Minimum valid parameter value. Used only when the ``type`` attribute value is ``data``, ``float``, or ``integer``. | False
``max`` | Maximum valid parameter value. Used only when the ``type`` attribute value is ``data``, ``float``, or ``integer``. | False


#### ``boolean``

This represents a binary true or false value.




##### Attributes

Attribute | Details | Required
--- | --- | ---
``checked`` | Set to ``true`` if the ``boolean`` parameter should be checked (or ``true``) by default. Used only when the ``type`` attribute value is ``boolean``. | False
``truevalue`` | The parameter value in the Cheetah template if the parameter is ``true`` or checked by the user. Used only when the ``type`` attribute value is ``boolean``. | False
``falsevalue`` | The parameter value in the Cheetah template if the parameter is ``false`` or not checked by the user. Used only when the ``type`` attribute value is ``boolean``. | False


#### ``data``

A dataset from the current history. Multiple types might be used for the param form.

##### Examples

The following will find all "coordinate interval files" contained within the
current history and dynamically populate a select list with them. If they are
selected, their destination and internal file name will be passed to the
appropriate command line variable.

```xml
<param name="interval_file" type="data" format="interval" label="near intervals in"/>
```

The following demonstrates a ``param`` which may accept multiple files and
multiple formats.

```xml
<param format="sam,bam" multiple="true" name="bamOrSamFile" type="data"
       label="Alignments in BAM or SAM format"
       help="The set of aligned reads." />
```

Perhaps counter-intuitively, a ``multiple="true"`` data parameter requires at least one
data input. If ``optional="true"`` is specified, this condition is relaxed and the user
is allowed to select 0 datasets. Unfortunately, if 0 datasets are selected the resulting
value for the parameter during Cheetah templating (such as in a ``command`` block) will
effectively be a list with one ``None``-like entity in it.

The following idiom can be used to iterate over such a list and build a hypothetical ``-B``
parameter for each file - the ``if`` block is used to handle the case where a ``None``-like
entity appears in the list because no files were selected:

```
#for $input in $input1
    #if $input
        -B "$input"
    #end if
#end for
```

Some example tools using ``multiple="true"`` data parameters include:

- [multi_data_param.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/multi_data_param.xml)
- [multi_data_optional.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/multi_data_optional.xml)

Additionally, a detailed discussion of handling multiple homogenous files can be found in the
the [Planemo Documentation](https://planemo.readthedocs.io/en/latest/writing_advanced.html#consuming-collections)
on this topic.




##### Attributes

Attribute | Details | Required
--- | --- | ---
``load_contents`` | Number of bytes that should be loaded into the `contents` attribute of the jobs dictionary provided to Expression Tools. Used only when the ``type`` attribute value is ``data``. | False
``optional`` | If ``false``, parameter must have a value. Defaults to ``false`` except when the ``type`` attribute value is ``select`` and ``multiple`` is ``true``. | False
``min`` | Minimum valid parameter value. Used only when the ``type`` attribute value is ``data``, ``float``, or ``integer``. | False
``max`` | Maximum valid parameter value. Used only when the ``type`` attribute value is ``data``, ``float``, or ``integer``. | False
``format`` | The comma-separated list of accepted data formats for this input. The list of supported data formats is contained in the [/config/datatypes_conf.xml.sample](https://github.com/galaxyproject/galaxy/blob/dev/config/datatypes_conf.xml.sample) file (use the file extension). Used only when the ``type`` attribute value is ``data`` or ``data_collection``. | False
``multiple`` | Allow multiple values to be selected. ``select`` parameters with ``multiple="true"`` are optional by default. Used only when the ``type`` attribute value is ``data``, ``group_tag``, or ``select``. | False


#### ``group_tag``




##### Attributes

Attribute | Details | Required
--- | --- | ---
``multiple`` | Allow multiple values to be selected. ``select`` parameters with ``multiple="true"`` are optional by default. Used only when the ``type`` attribute value is ``data``, ``group_tag``, or ``select``. | False


#### ``select``

The following will create a select list containing the options "Downstream" and
"Upstream". Depending on the selection, a ``d`` or ``u`` value will be passed to
the ``$upstream_or_down`` variable on the command line.

```xml
<param name="upstream_or_down" type="select" label="Get">
  <option value="u">Upstream</option>
  <option value="d">Downstream</option>
</param>
```

The following will create a checkbox list allowing the user to select
"Downstream", "Upstream", both, or neither. Depending on the selection, the
value of ``$upstream_or_down`` will be ``d``, ``u``, ``u,d``, or "".

```xml
<param name="upstream_or_down" type="select" label="Get" multiple="true" display="checkboxes">
  <option value="u">Upstream</option>
  <option value="d">Downstream</option>
</param>
```




##### Attributes

Attribute | Details | Required
--- | --- | ---
``data_ref`` | Used with select lists whose options are dynamically generated based on certain metadata attributes of the dataset or collection upon which this parameter depends (usually but not always the tool's input dataset). Used only when the ``type`` attribute value is ``data_column``, ``group_tag``, or ``select``. | False
``display`` | Render a select list as a set of checkboxes (``checkboxes``; note this is incompatible with ``multiple="false"`` and ``optional="false"``) or radio buttons (``radio``; note this is incompatible with ``multiple="true"`` and ``optional="true"``). Defaults to a drop-down menu select list. Used only when the ``type`` attribute value is ``select``. | False
``multiple`` | Allow multiple values to be selected. ``select`` parameters with ``multiple="true"`` are optional by default. Used only when the ``type`` attribute value is ``data``, ``group_tag``, or ``select``. | False
``dynamic_options`` | Deprecated/discouraged method to allow access to Python code to generate options for a select list. See ``code``'s documentation for an example. | False


#### ``data_column``

This parameter type is used to select columns from a parameter.




##### Attributes

Attribute | Details | Required
--- | --- | ---
``force_select`` | *Deprecated*. This is the inverse of ``optional``. Set to ``false`` to not force user to select an option in the list. Used only when the ``type`` attribute value is ``data_column``. | False
``numerical`` | If ``true`` a data column will be treated as numerical when filtering columns based on metadata. Used only when the ``type`` attribute value is ``data_column``. | False


#### ``drill_down``




##### Attributes

Attribute | Details | Required
--- | --- | ---
``hierarchy`` | Determine if a drill down is ``recursive`` or ``exact``. Used only when the ``type`` attribute value is ``drill_down``. | False


#### ``data_collection``

The following will create a parameter that only accepts paired FASTQ files grouped into a collection.

##### Examples

```xml
<param name="inputs" type="data_collection" collection_type="paired" label="Input FASTQs" format="fastq">
</param>
```

More detailed information on writing tools that consume collections can be found
in the [planemo documentation](https://planemo.readthedocs.io/en/latest/writing_advanced.html#collections).




##### Attributes

Attribute | Details | Required
--- | --- | ---
``format`` | The comma-separated list of accepted data formats for this input. The list of supported data formats is contained in the [/config/datatypes_conf.xml.sample](https://github.com/galaxyproject/galaxy/blob/dev/config/datatypes_conf.xml.sample) file (use the file extension). Used only when the ``type`` attribute value is ``data`` or ``data_collection``. | False
``collection_type`` | Restrict the kind of collection that can be consumed by this parameter (e.g. ``paired``, ``list:paired``, ``list``). Multiple such collection types can be specified here as a comma-separated list. Used only when the ``type`` attribute value is ``data_collection``. | False


#### ``color``

##### Examples

The following example will create a color selector parameter.

```xml
<param name="feature_color" type="color" label="Default feature color" value="#ff00ff">
</param>
```

Given that the output includes a pound sign, it is often convenient to use a
sanitizer to prevent Galaxy from escaping the result.

```xml
<param name="feature_color" type="color" label="Default feature color" value="#ff00ff">
  <sanitizer>
    <valid initial="string.ascii_letters,string.digits">
      <add value="#" />
    </valid>
  </sanitizer>
</param>
```




##### Attributes

Attribute | Details | Required
--- | --- | ---
``value`` | The default value for this parameter. | False
``rgb`` | If ``false``, the returned value will be in Hex color code. If ``true``, it will be a RGB value e.g. ``0,0,255``. Used only when the ``type`` attribute value is ``color``. | False


#### ``directory_uri``

This is used to tie into galaxy.files URI infrastructure. This should only be used by
core Galaxy tools until the interface around files has stabilized.

Currently ``directory_uri`` parameters provide user's the option of selecting a writable
directory destination for unstructured outputs of tools (e.g. history exports).

This covers examples of the most common parameter types, the remaining parameter
types are more obsecure and less likely to be useful for most tool authors.




### Attributes

Attribute | Details | Required
--- | --- | ---
``type`` | Describes the parameter type - each different type as different semantics and the tool form widget is different. Currently valid parameter types are: ``text``,  ``integer``,  ``float``,  ``boolean``,  ``genomebuild``,  ``select``, ``color``,  ``data_column``,  ``hidden``,  ``hidden_data``,  ``baseurl``, ``file``,  ``ftpfile``,  ``data``,  ``data_collection``,  ``library_data``, ``drill_down``. The definition of supported parameter types as defined in the ``parameter_types`` dictionary in [/lib/galaxy/tools/parameters/basic.py](https://github.com/galaxyproject/galaxy/blob/master/lib/galaxy/tools/parameters/basic.py). | True
``name`` | Name for this element. This ``name`` is used as the Cheetah variable containing the user-supplied parameter name in ``command`` and ``configfile`` elements. The name should not contain pipes or periods (e.g. ``.``). Some "reserved" names are ``REDIRECT_URL``, ``DATA_URL``, ``GALAXY_URL``. | False
``area`` | Boolean indicating if this should be rendered as a one line text box (if ``false``, the default) or a multi-line text  area (if ``true``). Used only when the ``type`` attribute value is ``text``. | False
``argument`` | If the parameter reflects just one command line argument of a certain tool, this tag should be set to that particular argument. It is rendered in parenthesis after the help section, and it will create the name attribute (if not given explicitly) from the argument attribute by stripping leading dashes and replacing all remaining dashes by underscores (e.g. if ``argument="--long-parameter"`` then ``name="long_parameter"`` is implicit). | False
``label`` | The attribute value will be displayed on the tool page as the label of the form field (``label="Sort Query"``). | False
``help`` | Short bit of text, rendered on the tool form just below the associated field to provide information about the field. Find the Intergalactic Utilities Commision suggested best practices for this element [here](https://planemo.readthedocs.io/en/latest/standards/docs/best_practices/tool_xml.html#parameter-help). | False
``load_contents`` | Number of bytes that should be loaded into the `contents` attribute of the jobs dictionary provided to Expression Tools. Used only when the ``type`` attribute value is ``data``. | False
``value`` | The default value for this parameter. | False
``default_value`` | *Deprecated*. Specify default value for column parameters (use ``value`` instead). | False
``optional`` | If ``false``, parameter must have a value. Defaults to ``false`` except when the ``type`` attribute value is ``select`` and ``multiple`` is ``true``. | False
``rgb`` | If ``false``, the returned value will be in Hex color code. If ``true``, it will be a RGB value e.g. ``0,0,255``. Used only when the ``type`` attribute value is ``color``. | False
``min`` | Minimum valid parameter value. Used only when the ``type`` attribute value is ``data``, ``float``, or ``integer``. | False
``max`` | Maximum valid parameter value. Used only when the ``type`` attribute value is ``data``, ``float``, or ``integer``. | False
``format`` | The comma-separated list of accepted data formats for this input. The list of supported data formats is contained in the [/config/datatypes_conf.xml.sample](https://github.com/galaxyproject/galaxy/blob/dev/config/datatypes_conf.xml.sample) file (use the file extension). Used only when the ``type`` attribute value is ``data`` or ``data_collection``. | False
``collection_type`` | Restrict the kind of collection that can be consumed by this parameter (e.g. ``paired``, ``list:paired``, ``list``). Multiple such collection types can be specified here as a comma-separated list. Used only when the ``type`` attribute value is ``data_collection``. | False
``data_ref`` | Used with select lists whose options are dynamically generated based on certain metadata attributes of the dataset or collection upon which this parameter depends (usually but not always the tool's input dataset). Used only when the ``type`` attribute value is ``data_column``, ``group_tag``, or ``select``. | False
``accept_default`` | Documentation for PermissiveBoolean | False
``refresh_on_change`` | Force a reload of the tool panel when the value of this parameter changes to allow ``code`` file processing. See deprecation-like notice for ``code`` blocks. | False
``force_select`` | *Deprecated*. This is the inverse of ``optional``. Set to ``false`` to not force user to select an option in the list. Used only when the ``type`` attribute value is ``data_column``. | False
``use_header_names`` | If ``true``, Galaxy assumes the first row of ``data_ref`` is a header and builds the select list with these values rather than the more generic ``c1`` ... ``cN`` (i.e. it will be ``c1: head1`` ... ``cN: headN``). Note that the content of the Cheetah variable is still the column index. Used only when the ``type`` attribute value is ``data_column``. | False
``display`` | Render a select list as a set of checkboxes (``checkboxes``; note this is incompatible with ``multiple="false"`` and ``optional="false"``) or radio buttons (``radio``; note this is incompatible with ``multiple="true"`` and ``optional="true"``). Defaults to a drop-down menu select list. Used only when the ``type`` attribute value is ``select``. | False
``multiple`` | Allow multiple values to be selected. ``select`` parameters with ``multiple="true"`` are optional by default. Used only when the ``type`` attribute value is ``data``, ``group_tag``, or ``select``. | False
``numerical`` | If ``true`` a data column will be treated as numerical when filtering columns based on metadata. Used only when the ``type`` attribute value is ``data_column``. | False
``hierarchy`` | Determine if a drill down is ``recursive`` or ``exact``. Used only when the ``type`` attribute value is ``drill_down``. | False
``checked`` | Set to ``true`` if the ``boolean`` parameter should be checked (or ``true``) by default. Used only when the ``type`` attribute value is ``boolean``. | False
``truevalue`` | The parameter value in the Cheetah template if the parameter is ``true`` or checked by the user. Used only when the ``type`` attribute value is ``boolean``. | False
``falsevalue`` | The parameter value in the Cheetah template if the parameter is ``false`` or not checked by the user. Used only when the ``type`` attribute value is ``boolean``. | False
``size`` | *Deprecated*. Completely ignored since release 16.10. Used only when the ``type`` attribute value is ``text``. | False
``dynamic_options`` | Deprecated/discouraged method to allow access to Python code to generate options for a select list. See ``code``'s documentation for an example. | False


## ``tool`` > ``inputs`` > ``param`` > ``validator``



This tag set is contained within the ``<param>`` tag set - it applies a
validator to the containing parameter. Tool submission will fail if a
single validator fails. See the
[annotation_profiler](https://github.com/galaxyproject/tools-devteam/blob/master/tools/annotation_profiler/annotation_profiler.xml)
tool for an example of how to use this tag set.

Note that validators for parameters with ``optional="true"`` are not
executed if no value is given.

### Generic validators

- ``expression``: Check if a one line python expression given expression
evaluates to True. The expression is given is the content of the validator tag.

### Validators for ``data`` and ``data_collection`` parameters

In case of ``data_collection`` parameters and
``data`` parameters with ``multiple="true"`` these validators are executed
separately for each of the contained data sets. Note that, for ``data``
parameters a ``metadata`` validator is added automatically.

- ``metadata``: Check for missing metadata.
- ``unspecified_build``: Check of a build is defined.
- ``dataset_ok_validator``: Check if the data set is in state OK.
- ``dataset_metadata_in_range``: Check if a numeric metadata value is within
a given range.
- ``dataset_metadata_in_data_table``: Check if a metadata value is contained in a column of a data table.
- ``dataset_metadata_not_in_data_table``: Equivalent to ``dataset_metadata_in_data_table`` with ``negate="true"``.

Deprecated data validators:

- ``dataset_metadata_in_file``: Use data tables with ``dataset_metadata_in_data_table``.
Check if a metadata value is contained in a specific column of a file in the ``tool_data_path``
(which is set in Galaxy's config).

### Validators for textual inputs (``text``, ``select``, ...)

- ``regex``: Check if a regular expression **matches** the value, i.e. appears
at the beginning of the value. To enforce a match of the complete value use
``$`` at the end of the expression. The expression is given is the content 
of the validator tag. Note that for ``selects`` each option is checked
separately.
- ``length``: Check if the length of the value is within a range.
- ``empty_field``: Check if the string is not empty
- ``value_in_data_table``: Check if the value is
contained in a column of a given data table.
- ``value_not_in_data_table``: Equivalent to ``value_in_data_table`` with ``negate="true"``.

For selects (in particular with dynamically defined options) the following
validator is useful:

``no_options``: Check if options are available for a ``select`` parameter.
Useful for parameters with dynamically defined options.

### Validators for numeric inputs (``integer``, ``float``)

``in_range``: Check if the value is in a given range.

### Examples

The following demonstrates a simple validator ``unspecified_build`` ensuring
that a dbkey is present on the selected dataset. This example is taken from the
[extract_genomic_dna](https://github.com/galaxyproject/tools-iuc/blob/master/tools/extract_genomic_dna/extract_genomic_dna.xml#L42)
tool.

```xml
<param name="input" type="data" format="gff,interval" label="Fetch sequences for intervals in">
    <validator type="unspecified_build" />
</param>
```

Along the same line, the following example taken from
[samtools_mpileup](https://github.com/galaxyproject/tools-devteam/blob/master/tool_collections/samtools/samtools_mpileup/samtools_mpileup.xml)
ensures that a dbkey is present and that FASTA indices in the ``fasta_indexes``
tool data table are present.

```xml
<param format="bam" label="BAM file(s)" name="input_bam" type="data" min="1" multiple="true">
    <validator type="unspecified_build" />
    <validator type="dataset_metadata_in_data_table" metadata_name="dbkey" table_name="fasta_indexes" metadata_column="1"
               message="Sequences are not currently available for the specified build." />
</param>
```

In this older, somewhat deprecated example - a genome build of the dataset must
be stored in Galaxy clusters and the name of the genome (``dbkey``) must be one
of the values in the first column of file ``alignseq.loc`` - that could be
expressed with the validator. In general, ``dataset_metadata_in_file`` should be
considered deprecated in favor of

```xml
<validator type="dataset_metadata_in_data_table"
           metadata_name="dbkey"
           metadata_column="1"
           message="Sequences are not currently available for the specified build." />
```

A very common validator is simply ensure a Python expression is valid for a
specified value. In the following example - paths/names that downstream tools
use in filenames may not contain ``..``.

```xml
<validator type="expression" message="No two dots (..) allowed">'..' not in value</validator>
```



### Attributes

Attribute | Details | Required
--- | --- | ---
``type`` | Valid values are: ``expression``, ``regex``, ``in_range``, ``length``, ``metadata``, ``unspecified_build``, ``no_options``, ``empty_field``, ``dataset_metadata_in_data_table``, ``dataset_metadata_not_in_data_table``, ``value_in_data_table``, ``value_not_in_data_table``, ``dataset_ok_validator``, ``dataset_metadata_in_range``. Deprecated validator: ``dataset_metadata_in_file``. The list of supported validators is in the ``validator_types`` dictionary in [/lib/galaxy/tools/parameters/validation.py](https://github.com/galaxyproject/galaxy/blob/dev/lib/galaxy/tools/parameters/validation.py). | True
``message`` | The error message displayed on the tool form if validation fails. A placeholder string ``%s`` will be repaced by the ``value`` | False
``negate`` | Negates the result of the validator. | False
``check`` | Comma-seperated list of metadata fields to check for if type is ``metadata``. If not specified, all non-optional metadata fields will be checked unless they appear in the list of fields specified by the ``skip`` attribute. | False
``table_name`` | Tool data table name to check against if ``type`` is ``dataset_metadata_in_data_table``, ``dataset_metadata_not_in_data_table``, ``value_in_data_table``, or ``value_not_in_data_table``. See the documentation for [tool data tables](https://galaxyproject.org/admin/tools/data-tables) and [data managers](https://galaxyproject.org/admin/tools/data-managers/) for more information. | False
``filename`` | Deprecated: use ``dataset_metadata_in_data_table``. Tool data filename to check against if ``type`` is ``dataset_metadata_in_file``. File should be present Galaxy's ``tool-data`` directory. | False
``metadata_name`` | Target metadata attribute name for ``dataset_metadata_in_data_table``, ``dataset_metadata_not_in_data_table`` and ``dataset_metadata_in_file`` options. | False
``metadata_column`` | Target column for metadata attribute in ``dataset_metadata_in_data_table``, ``dataset_metadata_not_in_data_table``, ``value_in_data_table``, ``value_not_in_data_table``, and ``dataset_metadata_in_file`` options. This can be an integer index to the column or a column name. | False
``min`` | When the ``type`` attribute value is ``in_range``, ``length``, or ``dataset_metadata_in_range`` - this is the minimum number allowed. | False
``max`` | When the ``type`` attribute value is ``in_range``, ``length``, or ``dataset_metadata_in_range`` - this is the maximum number allowed. | False
``exclude_min`` | When the ``type`` attribute value is ``in_range``, ``length``, or ``dataset_metadata_in_range`` - this boolean indicates if the ``min`` value is allowed. | False
``exclude_max`` | When the ``type`` attribute value is ``in_range``, ``length``, or ``dataset_metadata_in_range`` - this boolean indicates if the ``max`` value is allowed. | False
``split`` | If ``type`` is ``dataset_metadata_in_file``, this attribute is the column separator to use for values in the specified file. This default is ``\t`` and due to a bug in older versions of Galaxy, should not be modified. | False
``skip`` | Comma-seperated list of metadata fields to skip if type is ``metadata``. If not specified, all non-optional metadata fields will be checked unless ``check`` attribute is specified. | False
``line_startswith`` | Deprecated. Used to indicate lines in the file being used for validation start with a this attribute value. For use with validator ``dataset_metadata_in_file`` | False
``substitute_value_in_message`` | Deprecated. This is now always done. | False


## ``tool`` > ``inputs`` > ``param`` > ``option``



See [/tools/filters/sorter.xml](https://github.com/galaxyproject/galaxy/blob/master/tools/filters/sorter.xml)
for typical examples of how to use this tag set. This directive is used to described
static lists of options and is contained
within the [param](#tool-inputs-param) directive when the ``type`` attribute
value is ``select`` (i.e. ``<param type="select" ...>``).

### Example

```xml
<param name="style" type="select" label="with flavor">
    <option value="num">Numerical sort</option>
    <option value="gennum">General numeric sort</option>
    <option value="alpha">Alphabetical sort</option>
</param>
```

An option can also be annotated with ``selected="true"`` to specify a
default option.

```xml
<param name="col" type="select" label="From">
    <option value="0" selected="true">Column 1 / Sequence name</option>
    <option value="1">Column 2 / Source</option>
    <option value="2">Column 3 / Feature</option>
    <option value="6">Column 7 / Strand</option>
    <option value="7">Column 8 / Frame</option>
</param>
```




### Attributes

Attribute | Details | Required
--- | --- | ---
``value`` | The value of the corresponding variable when used the Cheetah template. Also the value that should be used in building test cases and used when building requests for the API. | False
``selected`` | A boolean parameter indicating if the corresponding option is selected by default (the default is ``false``). | False


## ``tool`` > ``inputs`` > ``param`` > ``conversion``



A contrived example of a tool that uses this is the test tool
[explicit_conversion.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/explicit_conversion.xml).

This directive is optionally contained within the ``<param>`` tag when the
``type`` attribute value is ``data`` and is used to dynamically generated a converted
dataset for the contained input of the type specified using the ``type`` tag.





### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | Name of Cheetah variable to create for converted dataset. | True
``type`` | The short extension describing the datatype to convert to - Galaxy must have a datatype converter from the parent input's type to this. | True


## ``tool`` > ``inputs`` > ``param`` > ``options``



See [/tools/extract/liftOver_wrapper.xml](https://github.com/galaxyproject/galaxy/blob/master/tools/extract/liftOver_wrapper.xml)
for an example of how to use this tag set. This tag set is optionally contained
within the ``<param>`` tag when the ``type`` attribute value is ``select`` or
``data`` and used to dynamically generated lists of options. This tag set
dynamically creates a list of options whose values can be
obtained from a predefined file stored locally or a dataset selected from the
current history.

There are at least five basic ways to use this tag - four of these correspond to
a ``from_XXX`` attribute on the ``options`` directive and the other is to
exclusively use ``filter``s to populate options.

* ``from_data_table`` - The options for the select list are dynamically obtained
  from a file specified in the Galaxy configuration file
  ``tool_data_table_conf.xml`` or from a Tool Shed installed data manager.
* ``from_dataset`` - The options for the select list are dynamically obtained
  from input dataset selected for the tool from the current history.
* ``from_file`` - The options for the select list are dynamically obtained from
  a file. This mechanis is discourage in favor of the more generic
  ``from_data_table``.
* ``from_parameter`` - The options for the select list are dynamically obtained
  from a parameter.
* Using ``filter``s - various filters can be used to populate options, see
  examples in the [filter](#tool-inputs-param-options-filter) documentation.

### ``from_data_table``

See Galaxy's
[data tables documentation](https://galaxyproject.org/admin/tools/data-tables)
for information on setting up data tables.

Once a data table has been configured and populated, these can be easily
leveraged via tools.

This ``conditional`` block in the
[bowtie2](https://github.com/galaxyproject/tools-devteam/blob/master/tools/bowtie2/bowtie2_wrapper.xml)
wrapper demonstrates using ``from_data_table`` options as an
alternative to local reference data.

```xml
<conditional name="reference_genome">
  <param name="source" type="select" label="Will you select a reference genome from your history or use a built-in index?" help="Built-ins were indexed using default options. See `Indexes` section of help below">
    <option value="indexed">Use a built-in genome index</option>
    <option value="history">Use a genome from the history and build index</option>
  </param>
  <when value="indexed">
    <param name="index" type="select" label="Select reference genome" help="If your genome of interest is not listed, contact the Galaxy team">
      <options from_data_table="bowtie2_indexes">
        <filter type="sort_by" column="2"/>
      </options>
      <validator type="no_options" message="No indexes are available for the selected input dataset"/>
    </param>
  </when>
  <when value="history">
    <param name="own_file" type="data" format="fasta" label="Select reference genome" />
  </when>
</conditional>
```

A minimal example wouldn't even need the ``filter`` or ``validator`` above, but
they are frequently nice features to add to your wrapper and can improve the user
experience of a tool.

### ``from_dataset``

The following example is taken from the Mothur tool
[remove.lineage.xml](https://github.com/galaxyproject/tools-iuc/blob/master/tools/mothur/remove.lineage.xml)
and demonstrates generating options from a dataset directly.

```xml
<param name="taxonomy" type="data" format="mothur.seq.taxonomy" label="taxonomy - Taxonomy" help="please make sure your file has no quotation marks in it"/>
<param name="taxons" type="select" optional="true" multiple="true" label="Browse Taxons from Taxonomy">
    <options from_dataset="taxonomy">
        <column name="name" index="1"/>
        <column name="value" index="1"/>
        <filter type="unique_value" name="unique_taxon" column="1"/>
        <filter type="sort_by" name="sorted_taxon" column="1"/>
    </options>
    <sanitizer>
        <valid initial="default">
            <add preset="string.printable"/>
            <add value=";"/>
            <remove value="&quot;"/>
            <remove value="&apos;"/>
        </valid>
    </sanitizer>
</param>
```

Starting from Galaxy v21.01, ``meta_file_key`` can be used together with
``from_dataset``. In such cases, options are generated using the dataset's
medadata file that the ``meta_file_key`` implies, instead of the dataset
itself.

```xml
<param name="input" type="data" format="maf" label="MAF File"/>
<param name="species" type="select" optional="False" label="Select species for the input dataset" multiple="True">
    <options from_dataset="input" meta_file_key="species_chromosomes">
        <column name="name" index="0"/>
        <column name="value" index="0"/>
    </options>
</param>
<param name="input_2" type="data_collection" collection_type="list" format="maf" label="MAF Collection" multiple="true" />
<param name="species_2" type="select" optional="false" label="Select species for the input dataset" multiple="true">
    <options from_dataset="input_2" meta_file_key="species_chromosomes" >
        <column name="name" index="0"/>
        <column name="value" index="0"/>
        <filter type="unique_value" name="unique_param" column="0"/>
  </options>
</param>
```

Filters can be used to generate options from dataset directly also as the
example below demonstrates (many more examples are present in the
[filter](#tool-inputs-param-options-filter) documentation).

```xml
<param name="species1" type="select" label="When Species" multiple="false">
    <options>
        <filter type="data_meta" ref="input1" key="species" />
    </options>
</param>
```

### ``from_file``

The following example is for Blast databases. In this example users maybe select
a database that is pre-formatted and cached in Galaxy clusters. When a new
dataset is available, admins must add the database to the local file named
"blastdb.loc". All such databases in that file are included in the options of
the select list. For a local instance, the file (e.g. ``blastdb.loc`` or
``alignseq.loc``) must be stored in the configured
[tool_data_path](https://github.com/galaxyproject/galaxy/tree/master/tool-data)
directory. In this example, the option names and values are taken from column 0
of the file.

```xml
<param name="source_select" type="select" display="radio" label="Choose target database">
    <options from_file="blastdb.loc">
        <column name="name" index="0"/>
        <column name="value" index="0"/>
    </options>
</param>
```

In general, ``from_file`` should be considered deprecated and  ``from_data_table``
should be prefered.

### ``from_parameter``

This variant of the ``options`` directive is discouraged because it exposes
internal Galaxy structures. See the older
[bowtie](https://github.com/galaxyproject/tools-devteam/blob/master/tools/bowtie_wrappers/bowtie_wrapper.xml)
wrappers for an example of these.

### Other Ways to Dynamically Generate Options

Though deprecated and discouraged, [code](#tool-code) blocks can also be
used to generate dynamic options.





### Attributes

Attribute | Details | Required
--- | --- | ---
``from_dataset`` | Determine options from the dataset given in the referred input parameter. If 'meta_file_key' is given, the options are determined from the data in the metadata file of the input. | False
``from_file`` | Deprecated. | False
``from_data_table`` | Determine options from a data table. | False
``from_parameter`` | Deprecated. | False
``options_filter_attribute`` | Deprecated. | False
``transform_lines`` | Deprecated. | False
``startswith`` | Ignore lines starting with the given character. | False
``meta_file_key`` | Works with from_dataset only. See [docs](#from-dataset) | False


## ``tool`` > ``inputs`` > ``param`` > ``options`` > ``column``

Optionally contained within an
``<options>`` tag set - specifies columns used in building select options from a
file stored locally (i.e. index or tool data) or a dataset in the
current history.

Any number of columns may be described, but at least one must be given the name
``value`` and it will serve as the value of this parameter in the Cheetah
template and elsewhwere (e.g. in API for instance).

If a column named ``name`` is defined, this too has special meaning and it will
be the value the tool form user sees for each option. If no ``name`` column
appears, ``value`` will serve as the name.

### Examples

The following fragment shows options from the dataset in the current history
that has been selected as the value of the parameter named ``input1``.

```xml
<options from_dataset="input1">
    <column name="name" index="0"/>
    <column name="value" index="0"/>
</options>
```

The [interval2maf](https://github.com/galaxyproject/galaxy/blob/dev/tools/maf/interval2maf.xml)
tool makes use of this tag with files from a history, and the
[star_fusion](https://github.com/galaxyproject/tools-iuc/blob/master/tools/star_fusion/star_fusion.xml)
tool makes use of this to reference a data table.



### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | Name given to the column with index ``index``, the names ``name`` and ``value`` have special meaning as described above. | True
``index`` | 0-based index of the column in the target file. | True


## ``tool`` > ``inputs`` > ``param`` > ``options`` > ``filter``

Optionally contained within an
``<options>`` tag set - modify (e.g. remove, add, sort, ...) the list of values obtained from a locally stored file (e.g.
a tool data table) or a dataset in the current history.

Currently the following filters are defined:

* ``static_value`` filter options for which the entry in a given ``column`` of the referenced file based on equality to the ``value`` attribute of the filter. 
* ``regexp`` similar to the ``static_value`` filter, but checks if the regular expression given by ``value`` matches the entry.
* ``param_value`` filter options for which the entry in a given ``column`` of the referenced file based on properties of another input parameter specified by ``ref``. This property is by default the value of the parameter, but also the values of another attribute (``ref_attribute``) of the parameter can be used, e.g. the extension of a data input.
* ``data_meta`` populate or filter options based on the metadata of another input parameter specified by ``ref``. If a ``column`` is given options are filtered for which the entry in this column ``column`` is equal to metadata of the input parameter specified by ``ref``. 
If no ``column`` is given the metadata value of the referenced input is added to the options list (in this case the corresponding ``options`` tag must not have the ``from_data_table`` or ``from_dataset`` attributes). 
In both cases the desired metadata is selected by ``key``.

The ``static_value`` and ``regexp`` filters can be inverted by setting ``keep`` to true.

* ``add_value``: add an option with a given ``name`` and ``value`` to the options. By default the new option is appended, with ``index`` the insertion position can be specified.
* ``remove_value``: remove a value from the options. Either specified explicitly with ``value``, the value of another input specifified with ``ref``, or the metatdata ``key`` of another input ``meta_ref``.
* ``unique_value``: remove options that have duplicate entries in the given ``column``.
* ``sort_by``: sort options by the entries of a given ``column``.
* ``multiple_splitter``: split the entries of the specified ``column``(s) in the referenced file using a ``separator``. Thereby the number of columns is increased. 

### Examples

The following example from Mothur's
[remove.groups.xml](https://github.com/galaxyproject/tools-iuc/blob/master/tools/mothur/remove.groups.xml)
tool demonstrates filtering a select list based on the metadata of an input to
to the tool.

```xml
<param name="group_in" type="data" format="mothur.groups,mothur.count_table" label="group or count table - Groups"/>
<param name="groups" type="select" label="groups - Pick groups to remove" multiple="true" optional="false">
    <options>
        <filter type="data_meta" ref="group_in" key="groups"/>
    </options>
</param>
```

This more advanced example, taken from Mothur's
[remove.lineage.xml](https://github.com/galaxyproject/tools-iuc/blob/master/tools/mothur/remove.lineage.xml)
tool demonstrates using filters to sort a list and remove duplicate entries.

```xml
<param name="taxonomy" type="data" format="mothur.cons.taxonomy" label="constaxonomy - Constaxonomy file. Provide either a constaxonomy file or a taxonomy file" help="please make sure your file has no quotation marks in it"/>
<param name="taxons" type="select" optional="true" multiple="true" label="Browse Taxons from Taxonomy">
    <options from_dataset="taxonomy">
        <column name="name" index="2"/>
        <column name="value" index="2"/>
        <filter type="unique_value" name="unique_taxon" column="2"/>
        <filter type="sort_by" name="sorted_taxon" column="2"/>
    </options>
    <sanitizer>
        <valid initial="default">
            <add preset="string.printable"/>
            <add value=";"/>
            <remove value="&quot;"/>
            <remove value="&apos;"/>
        </valid>
    </sanitizer>
</param>
```

This example taken from the
[hisat2](https://github.com/galaxyproject/tools-iuc/blob/master/tools/hisat2/hisat2.xml)
tool demonstrates filtering values from a tool data table.

```xml
<param help="If your genome of interest is not listed, contact the Galaxy team" label="Select a reference genome" name="index" type="select">
    <options from_data_table="hisat2_indexes">
        <filter column="2" type="sort_by" />
    </options>
    <validator message="No genomes are available for the selected input dataset" type="no_options" />
</param>
```

The
[gemini_load.xml](https://github.com/galaxyproject/tools-iuc/blob/master/tools/gemini/gemini_load.xml)
tool demonstrates adding values to an option list using ``filter``s.

```xml
<param name="infile" type="data" format="vcf" label="VCF file to be loaded in the GEMINI database" help="Only build 37 (aka hg19) of the human genome is supported.">
    <options>
        <filter type="add_value" value="hg19" />
        <filter type="add_value" value="Homo_sapiens_nuHg19_mtrCRS" />
        <filter type="add_value" value="hg_g1k_v37" />
    </options>
</param>
```

While this fragment from [maf_to_interval.xml](https://github.com/galaxyproject/galaxy/blob/dev/tools/maf/maf_to_interval.xml) demonstrates removing items.

```xml
<param name="species" type="select" label="Select additional species"
       display="checkboxes" multiple="true"
       help="The species matching the dbkey of the alignment is always included.
       A separate history item will be created for each species.">
    <options>
        <filter type="data_meta" ref="input1" key="species" />
        <filter type="remove_value" meta_ref="input1" key="dbkey" />
    </options>
</param>
```

This example taken from
[snpSift_dbnsfp.xml](https://github.com/galaxyproject/tools-iuc/blob/master/tool_collections/snpsift/snpsift_dbnsfp/snpSift_dbnsfp.xml)
demonstrates splitting up strings into multiple values.

```xml
<param name="annotations" type="select" multiple="true" display="checkboxes" label="Annotate with">
    <options from_data_table="snpsift_dbnsfps">
        <column name="name" index="4"/>
        <column name="value" index="4"/>
        <filter type="param_value" ref="dbnsfp" column="3" />
        <filter type="multiple_splitter" column="4" separator=","/>
    </options>
</param>
```



### Attributes

Attribute | Details | Required
--- | --- | ---
``type`` | Currently the filters in the ``filter_types`` dictionary in the module [/lib/galaxy/tools/parameters/dynamic_options.py](https://github.com/galaxyproject/galaxy/blob/master/lib/galaxy/tools/parameters/dynamic_options.py) are defined.   Deprecated filter types:  * ``attribute_value_splitter`` | True
``column`` | Column targeted by this filter given as column index or a column name. Invalid if ``type`` is ``add_value`` or ``remove_value``. | False
``name`` | Name displayed for value to add (only used with ``type`` of ``add_value``). | False
``ref`` | The attribute name of the reference file (tool data) or input dataset. Only used when ``type`` is ``data_meta`` (required), ``param_value`` (required), or ``remove_value`` (optional). | False
``key`` | When ``type`` is ``data_meta``, ``param_value``, or ``remove_value`` - this is the name of the metadata key to filter by. | False
``multiple`` | For types ``data_meta`` and ``remove_value``, whether option values are multiple. Columns will be split by separator. Defaults to ``false``. | False
``separator`` | When ``type`` is ``data_meta``, ``multiple_splitter``, or ``remove_value`` - this is used to split one value into multiple parts. When ``type`` is ``data_meta`` or ``remove_value`` this is only used if ``multiple`` is set to ``true``. | False
``keep`` | If ``true``, keep columns matching the value, if ``false`` discard columns matching the value. Used when ``type`` is either ``static_value``, ``regexp`` or ``param_value``. | False
``value`` | Target value of the operations - has slightly different meanings depending on ``type``. For instance when ``type`` is ``add_value`` it is the value to add to the list and when ``type`` is ``static_value`` or ``regexp`` it is the value compared against. | False
``ref_attribute`` | Only used when ``type`` is ``param_value``. Period (``.``) separated attribute chain of input (``ref``) attributes to use as value for filter. | False
``index`` | Used when ``type`` is ``add_value``, it is the index into the list to add the option to. If not set, the option will be added to the end of the list. | False
``meta_ref`` | Only used when ``type`` is ``remove_value``. Dataset to look for the value of metadata ``key`` to remove from the list. | False


## ``tool`` > ``inputs`` > ``param`` > ``sanitizer``



See
[/tools/filters/grep.xml](https://github.com/galaxyproject/galaxy/blob/dev/tools/filters/grep.xml)
for a typical example of how to use this tag set. This tag set is used to
replace the basic parameter sanitization with custom directives. This tag set is
contained within the ``<param>`` tag set - it contains a set of ``<valid>`` and
``<mapping>`` tags.

### Character presets

The following presets can be used when specifying the valid characters: the
[constants](https://docs.python.org/3/library/string.html#string-constants) from the ``string`` Python3 module,
plus ``default`` (equal to ``string.ascii_letters + string.digits + " -=_.()/+*^,:?!"``)
and ``none`` (empty set).
The ``string.letters``, ``string.lowercase`` and ``string.uppercase`` Python2
constants are accepted for backward compatibility, but are aliased to the
corresponding not locale-dependent constant (i.e. ``string.ascii_letters``,
``string.ascii_lowercase`` and ``string.ascii_uppercase`` respectively).

### Examples

This example specifies to use the empty string as the invalid character (instead
of the default ``X``, so invalid characters are effectively dropped instead of
replaced with ``X``) and indicates that the only valid characters for this input
are ASCII letters, digits, and ``_``.

```xml
<param name="mystring" type="text" label="Say something interesting">
    <sanitizer invalid_char="">
        <valid initial="string.ascii_letters,string.digits">
            <add value="_" />
        </valid>
    </sanitizer>
</param>
```

This example allows many more valid characters and specifies that ``&`` will just
be dropped from the input.

```xml
<sanitizer>
    <valid initial="string.printable">
        <remove value="&amp;"/>
    </valid>
    <mapping initial="none">
        <add source="&amp;" target=""/>
    </mapping>
</sanitizer>
```



### Attributes

Attribute | Details | Required
--- | --- | ---
``sanitize`` | This boolean parameter determines if the input is sanitized at all (the default is ``true``). | False
``invalid_char`` | The attribute specifies the character used as a replacement for invalid characters (the default is ``X``). | False


## ``tool`` > ``inputs`` > ``param`` > ``sanitizer`` > ``valid``

Contained within the
``<sanitizer>`` tag set, these are used to specify a list of allowed characters.
Contains ``<add>`` and ``<remove>`` tags.


### Attributes

Attribute | Details | Required
--- | --- | ---
``initial`` | This describes the initial characters to allow as valid, specified as a character preset (as defined above). The default is the ``default`` preset. | False


## ``tool`` > ``inputs`` > ``param`` > ``sanitizer`` > ``valid`` > ``add``

This directive is used to add individual
characters or preset lists of characters. Character must not be allowed as a
valid input for the mapping to occur.


### Attributes

Attribute | Details | Required
--- | --- | ---
``preset`` | Add the characters contained in the specified character preset (as defined above) to the list of valid characters. The default is the ``none`` preset. | False
``value`` | Add a character to the list of valid characters. | False


## ``tool`` > ``inputs`` > ``param`` > ``sanitizer`` > ``valid`` > ``remove``

This directive is used to remove
individual characters or preset lists of characters.
Character must not be allowed as a valid input for the mapping to occur.


### Attributes

Attribute | Details | Required
--- | --- | ---
``preset`` | Remove the characters contained in the specified character preset (as defined above) from the list of valid characters. The default is the ``none`` preset. | False
``value`` | A character to remove from the list of valid characters. | False


## ``tool`` > ``inputs`` > ``param`` > ``sanitizer`` > ``mapping``

Contained within the ``<sanitizer>`` tag set. Used to specify a mapping of disallowed character to replacement string. Contains ``<add>`` and ``<remove>`` tags.


### Attributes

Attribute | Details | Required
--- | --- | ---
``initial`` | Initial character mapping (default is ``galaxy.util.mapped_chars``) | False


## ``tool`` > ``inputs`` > ``param`` > ``sanitizer`` > ``mapping`` > ``add``

Use to add character mapping during sanitization. Character must not be allowed as a valid input for the mapping to occur.


### Attributes

Attribute | Details | Required
--- | --- | ---
``source`` | Replace all occurrences of this character with the string of ``target``. | False
``target`` | Replace all occurrences of ``source`` with this string | False


## ``tool`` > ``inputs`` > ``param`` > ``sanitizer`` > ``mapping`` > ``remove``

Use to remove character mapping during sanitization.


### Attributes

Attribute | Details | Required
--- | --- | ---
``source`` | Character to remove from mapping. | False


## ``tool`` > ``request_param_translation``

See [/tools/data_source/ucsc_tablebrowser.xml](https://github.com/galaxyproject/galaxy/blob/dev/tools/data_source/ucsc_tablebrowser.xml) for an example of how to use this tag set. This tag set is used only in "data_source" tools (i.e. whose ``tool_type`` attribute is ``data_source``). This tag set contains a set of [request_param](#tool-request-param-translation-request-param) elements.



## ``tool`` > ``request_param_translation`` > ``request_param``

Contained within the [request_param_translation](#tool-request-param-translation) tag set (used only in "data_source" tools). The external data source application may send back parameter names like "GENOME" which must be translated to "dbkey" in Galaxy.


### Attributes

Attribute | Details | Required
--- | --- | ---
``galaxy_name`` | Each of these maps directly to a ``remote_name`` value | True
``remote_name`` | The string representing the name of the parameter in the remote data source | True
``missing`` | The default value to use for ``galaxy_name`` if the ``remote_name`` parameter is not included in the request | False


## ``tool`` > ``request_param_translation`` > ``request_param`` > ``append_param``

Optionally contained within the [request_param](#tool-request-param-translation-request-param) element if ``galaxy_name="URL"``. Some remote data sources (e.g., Gbrowse, Biomart) send parameters back to Galaxy in the initial response that must be added to the value of "URL" prior to Galaxy sending the secondary request to the remote data source via URL.


### Attributes

Attribute | Details | Required
--- | --- | ---
``separator`` | The text to use to join the requested parameters together (example ``separator="&amp;"``). | True
``first_separator`` | The text to use to join the ``request_param`` parameters to the first requested parameter (example ``first_separator="?"``). | False
``join`` | The text to use to join the param name to its value (example ``join="="``). | True


## ``tool`` > ``request_param_translation`` > ``request_param`` > ``append_param`` > ``value``

Contained within the [append_param](#tool-request-param-translation-request-param-append-param) tag set. Allows for appending a param name / value pair to the value of URL.

Example:

```xml
<request_param_translation>
    <request_param galaxy_name="URL" remote_name="URL" missing="">
        <append_param separator="&amp;" first_separator="?" join="=">
            <value name="_export" missing="1" />
        </append_param>
    </request_param>
</request_param_tranlsation>
```



### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | Any valid HTTP request parameter name. The name / value pair must be received from the remote data source and will be appended to the value of URL as something like ``"&_export=1"`` (e.g. ``name="_export"``). | True
``missing`` | Must be a valid HTTP request parameter value (e.g. ``missing="1"``). | True


## ``tool`` > ``request_param_translation`` > ``request_param`` > ``value_translation``

Optionally contained within the [request_param](#tool-request-param-translation-request-param) tag set. The parameter value received from a remote data source may be named differently in Galaxy, and this tag set allows for the value to be appropriately translated.



## ``tool`` > ``request_param_translation`` > ``request_param`` > ``value_translation`` > ``value``

Contained within the [value_translation](#tool-request-param-translation-request-param-value-translation) tag set - allows for changing the data type value to something supported by Galaxy.

Example:

```xml
<request_param_translation>
    <request_param galaxy_name="data_type" remote_name="hgta_outputType" missing="bed" >
        <value_translation>
            <value galaxy_value="tabular" remote_value="primaryTable" />
        </value_translation>
    </request_param>
</request_param_tranlsation>
```



### Attributes

Attribute | Details | Required
--- | --- | ---
``galaxy_value`` | The target value (e.g. for setting data format: the list of supported data formats is contained in the [/config/datatypes_conf.xml.sample](https://github.com/galaxyproject/galaxy/blob/dev/config/datatypes_conf.xml.sample). | True
``remote_value`` | The value supplied by the remote data source application | True


## ``tool`` > ``outputs``


Container tag set for the ``<data>`` and ``<collection>`` tag sets.
The files and collections created by tools as a result of their execution are
named by Galaxy. You specify the number and type of your output files using the
contained ``<data>`` and ``<collection>`` tags. These may be passed to your tool
executable through using line variables just like the parameters described in
the ``<inputs>`` documentation.



### Attributes

Attribute | Details | Required
--- | --- | ---
``provided_metadata_style`` | Style used for tool provided metadata file (i.e. [galaxy.json](https://planemo.readthedocs.io/en/latest/writing_advanced.html#tool-provided-metadata)) - this can be either "legacy" or "default". The default of tools with a profile of 17.09 or newer are "default", and "legacy" for older and tools and tools without a specified profile. A discussion of the differences between the styles can be found [here](https://github.com/galaxyproject/galaxy/pull/4437). | False
``provided_metadata_file`` | Path relative to tool's working directory to load tool provided metadata from. This metadata can describe dynamic datasets to load, dynamic collection contents, as well as simple metadata (e.g. name, dbkey, etc...) and datatype-specific metadata for declared outputs. More information can be found [here](https://planemo.readthedocs.io/en/latest/writing_advanced.html#tool-provided-metadata). The default is ``galaxy.json``. | False


## ``tool`` > ``outputs`` > ``data``



This tag set is contained within the ``<outputs>`` tag set, and it defines the
output data description for the files resulting from the tool's execution. The
value of the attribute ``label`` can be acquired from input parameters or metadata
in the same way that the command line parameters are (discussed in the
``<command>`` tag set section above).

### Examples

The following will create a variable called ``$out_file1`` with data type
``pdf``.

```xml
<outputs>
    <data format="pdf" name="out_file1" />
</outputs>
```

The valid values for format can be found in
[/config/datatypes_conf.xml.sample](https://github.com/galaxyproject/galaxy/blob/dev/config/datatypes_conf.xml.sample).

The following will create a dataset in the history panel whose data type is the
same as that of the input dataset selected (and named ``input1``) for the tool.

```xml
<outputs>
    <data format_source="input1" name="out_file1" metadata_source="input1"/>
</outputs>
```

The following will create datasets in the history panel, setting the output data
type to be the same as that of an input dataset named by the ``format_source``
attribute. Note that a conditional name is not included, so 2 separate
conditional blocks should not contain parameters with the same name.

```xml
<inputs>
    <!-- fasta may be an aligned fasta that subclasses Fasta -->
    <param name="fasta" type="data" format="fasta" label="fasta - Sequences"/>
    <conditional name="qual">
        <param name="add" type="select" label="Trim based on a quality file?" help="">
            <option value="no">no</option>
            <option value="yes">yes</option>
        </param>
        <when value="no"/>
        <when value="yes">
            <!-- qual454, qualsolid, qualillumina -->
            <param name="qfile" type="data" format="qual" label="qfile - a quality file"/>
        </when>
    </conditional>
</inputs>
<outputs>
    <data format_source="fasta" name="trim_fasta"
          label="${tool.name} on ${on_string}: trim.fasta"/>
    <data format_source="qfile" name="trim_qual"
          label="${tool.name} on ${on_string}: trim.qual">
        <filter>qual['add'] == 'yes'</filter>
    </data>
</outputs>
```

Assume that the tool includes an input parameter named ``database`` which is a
select list (as shown below). Also assume that the user selects the first option
in the ``$database`` select list. Then the following will ensure that the tool
produces a tabular data set whose associated history item has the label ``Blat
on Human (hg18)``.

```xml
<inputs>
    <param format="tabular" name="input" type="data" label="Input stuff"/>
    <param type="select" name="database" label="Database">
        <option value="hg18">Human (hg18)</option>
        <option value="dm3">Fly (dm3)</option>
    </param>
</inputs>
<outputs>
    <data format="input" name="output" label="Blat on ${database.value_label}" />
</outputs>
```




### Attributes

Attribute | Details | Required
--- | --- | ---
``format`` | The short name for the output datatype. The valid values for format can be found in [/config/datatypes_conf.xml.sample](https://github.com/galaxyproject/galaxy/blob/dev/config/datatypes_conf.xml.sample) (e.g. ``format="pdf"`` or ``format="fastqsanger"``). For collections this is the default format for all included elements. Note that the format specified here is ignored for discovered data sets. | False
``format_source`` | This sets the data type of the output dataset(s) to be the same format as that of the specified tool input. | False
``label`` | This will be the name of the history item for the output data set. The string can include structure like ``${<some param name>.<some attribute>}``, as discussed for command line parameters in the ``<command>`` tag set section above. The default label is ``${tool.name} on ${on_string}``. | False
``name`` | Name for this output. This ``name`` is used as the Cheetah variable containing the Galaxy assigned output path in ``command`` and ``configfile`` elements. The name should not contain pipes or periods (e.g. ``.``). | True
``auto_format`` | If ``true``, this output will sniffed and its format determined automatically by Galaxy. | False
``default_identifier_source`` | Sets the source of element identifier to the specified input. This only applies to collections that are mapped over a non-collection input and that have equivalent structures. If this references input elements in conditionals, this value should be qualified (e.g. ``cond|input`` instead of ``input`` if ``input`` is in a conditional with ``name="cond"``). | False
``metadata_source`` | This copies the metadata information from the tool's input dataset. This is particularly useful for interval data types where the order of the columns is not set. | False
``from_work_dir`` | Relative path to a file produced by the tool in its working directory. Output's contents are set to this file's contents. The behaviour when this file does not exist in the working directory is undefined; the resulting dataset could be empty or the tool execution could fail. | False
``hidden`` | Boolean indicating whether to hide dataset in the history view. (Default is ``false``.) | False


## ``tool`` > ``outputs`` > ``data`` > ``filter``


The ``<data>`` tag can contain a ``<filter>`` tag which includes a Python code
block to be executed to test whether to include this output in the outputs the
tool ultimately creates. If the code, when executed, returns ``True``,
the output dataset is retained. In these code blocks the tool parameters appear
as Python variables and are thus referred to without the $ used for the Cheetah
template (used in the ``<command>`` tag). Variables that are part of
conditionals are accessed using a dictionary named after the conditional. Boolean
parameters appear as booleans, not the value of their ``truevalue`` and
``falsevalue`` attributes. In the example below, ``options["selection_mode"]`` would
appear as ``$options.selection_mode`` in Cheetah. Similarly ``options["vcf_output"]``
would appear as ``$options.vcf_output`` having the values ``'--vcf'`` when true and
``''`` when false in Cheetah.
Note that also parameters in sections are accessed via a dictionary.

### Example

```xml
    <inputs>
      <param type="data" format="fasta" name="reference_genome" label="Reference genome" />
      <param type="data" format="bam" name="input_bam" label="Aligned reads" />
      <conditional name="options">
        <param label="Use advanced options" name="selection_mode" type="select">
          <option selected="true" value="defaults">Use default options</option>
          <option value="advanced">Use advanced options</option>
        </param>
        <when value="defaults" />
        <when value="advanced">
          <param name="vcf_output" type="boolean" checked="false" label="VCF output"
            truevalue="--vcf" falsevalue="" />
        </when>
      </conditional>
    </inputs>
    <outputs>
      <data format="txt" label="Alignment report on ${on_string}" name="output_txt" />
      <data format="vcf" label="Variant summary on ${on_string}" name="output_vcf">
          <filter>options['selection_mode'] == 'advanced' and options['vcf_output']</filter>
      </data>
    </outputs>
```

Note that variables that correspond to optional select parameters are `None` if nothing is selected. 
Therefore a filter for such a variable looks like the following example.

### Example

```xml
    <inputs>
       <param name="output_type" type="select" optional="true">
            <option value="save_phase">Phase Movie</option>
            <option value="save_period">Period Movie</option>
        </param>
    </inputs>

    <outputs>
        <data name="phase_out" format="tiff">
            <filter>output_type and "save_phase" in output_type</filter>
        </data>
        <data name="period_out" format="tiff" label="${movie.name[:-4]}_period">
            <filter>output_type and "save_period" in output_type</filter>
        </data>
    </outputs>
```





## ``tool`` > ``outputs`` > ``data`` > ``change_format``

See
[extract_genomic_dna.xml](https://github.com/galaxyproject/tools-iuc/blob/master/tools/extract_genomic_dna/extract_genomic_dna.xml)
or the test tool
[output_format.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/output_format.xml)
for simple examples of how this tag set is used in a tool. This tag set is
optionally contained within the ``<data>`` tag set and is the container tag set
for the following ``<when>`` tag set.



## ``tool`` > ``outputs`` > ``data`` > ``change_format`` > ``when``



If the data type of the output dataset is the specified type, the data type is
changed to the desired type.

### Examples

Assume that your tool config includes the following select list parameter
structure:

```xml
<param name="out_format" type="select" label="Output data type">
    <option value="fasta">FASTA</option>
    <option value="interval">Interval</option>
</param>
```

Then whenever the user selects the ``interval`` option from the select list, the
following structure in your tool config will override the ``format="fasta"`` setting
in the ``<data>`` tag set with ``format="interval"``.

```xml
<outputs>
    <data format="fasta" name="out_file1">
        <change_format>
            <when input="out_format" value="interval" format="interval" />
        </change_format>
    </data>
</outputs>
```

See
[extract_genomic_dna.xml](https://github.com/galaxyproject/tools-iuc/blob/master/tools/extract_genomic_dna/extract_genomic_dna.xml)
or the test tool
[output_format.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/output_format.xml)
for more examples.




### Attributes

Attribute | Details | Required
--- | --- | ---
``input`` | This attribute should be the name of the desired input parameter (e.g. ``input="out_format"`` above). | False
``value`` | This must be a possible value of the ``input`` parameter (e.g. ``value="interval"`` above), or of the deprecated ``input_dataset``'s attribute. | True
``format`` | This value must be a supported data type (e.g. ``format="interval"``). See [/config/datatypes_conf.xml.sample](https://github.com/galaxyproject/galaxy/blob/dev/config/datatypes_conf.xml.sample) for a list of supported formats. | True
``input_dataset`` | *Deprecated*. | False
``attribute`` | *Deprecated*. | False


## ``tool`` > ``outputs`` > ``data`` > ``actions``



The ``actions`` directive allows tools to dynamically take actions related to an
``output`` either unconditionally or conditionally based on inputs. These
actions currently include setting metadata values and the output's data format.

The examples below will demonstrate that the ``actions`` tag contains child
``conditional`` tags. The these conditionals are met, additional ``action``
directives below the conditional are apply to the ``data`` output.

### Metadata

The ``<actions>`` in the Bowtie 2 wrapper is used in lieu of the deprecated
``<code>`` tag to set the ``dbkey`` of the output dataset. In
[bowtie2_wrapper.xml](https://github.com/galaxyproject/tools-devteam/blob/master/tools/bowtie2/bowtie2_wrapper.xml)
(see below), according to the first action block, if the
``reference_genome.source`` is ``indexed`` (not ``history``), then it will assign
the ``dbkey`` of the output file to be the same as that of the reference file. It
does this by looking at through the data table and finding the entry that has the
value that's been selected in the index dropdown box as column 1 of the loc file
entry and using the dbkey, in column 0 (ignoring comment lines (starting with #)
along the way).

If ``reference_genome.source`` is ``history``, it pulls the ``dbkey`` from the
supplied file.

```xml
<data format="bam" name="output" label="${tool.name} on ${on_string}: aligned reads (sorted BAM)">
  <filter>analysis_type['analysis_type_selector'] == "simple" or analysis_type['sam_opt'] is False</filter>
  <actions>
    <conditional name="reference_genome.source">
      <when value="indexed">
        <action type="metadata" name="dbkey">
          <option type="from_data_table" name="bowtie2_indexes" column="1" offset="0">
            <filter type="param_value" column="0" value="#" compare="startswith" keep="false"/>
            <filter type="param_value" ref="reference_genome.index" column="0"/>
          </option>
        </action>
      </when>
      <when value="history">
        <action type="metadata" name="dbkey">
          <option type="from_param" name="reference_genome.own_file" param_attribute="dbkey" />
        </action>
      </when>
    </conditional>
  </actions>
</data>
```

### Format

The Bowtie 2 example also demonstrates conditionally setting an output format
based on inputs, as shown below:

```xml
<data format="fastqsanger" name="output_unaligned_reads_r" label="${tool.name} on ${on_string}: unaligned reads (R)">
    <filter>(library['type'] == "paired" or library['type'] == "paired_collection") and library['unaligned_file'] is True</filter>
    <actions>
        <conditional name="library.type">
            <when value="paired">
                <action type="format">
                    <option type="from_param" name="library.input_2" param_attribute="ext" />
                </action>
            </when>
            <when value="paired_collection">
                <action type="format">
                    <option type="from_param" name="library.input_1" param_attribute="reverse.ext" />
                </action>
            </when>
        </conditional>
    </actions>
</data>
```

### Unconditional Actions and Column Names

For a static file that contains a fixed number of columns, it is straight forward:

```xml
<outputs>
    <data format="tabular" name="table">
        <actions>
            <action name="column_names" type="metadata" default="Firstname,Lastname,Age" />
        </actions>
    </data>
</outputs>
```

It may also be necessary to use column names based on a variable from another
input file. This is implemented in the
[htseq-count](https://github.com/galaxyproject/tools-iuc/blob/master/tools/htseq_count/htseq-count.xml)
and
[featureCounts](https://github.com/galaxyproject/tools-iuc/blob/master/tools/featurecounts/featurecounts.xml)
wrappers:

```xml
<inputs>
    <data name="input_file" type="data" multiple="false">
</inputs>
<outputs>
    <data format="tabular" name="output_short">
        <actions>
            <action name="column_names" type="metadata" default="Geneid,${input_file.name}" />
        </actions>
    </data>
</outputs>
```

Or in case of multiple files:

```xml
<inputs>
    <data name="input_files" type="data" multiple="true">
</inputs>
<outputs>
    <data format="tabular" name="output_short">
        <actions>
            <action name="column_names" type="metadata" default="Geneid,${','.join([a.name for a in $input_files])}" />
        </actions>
    </data>
</outputs>
```

### Unconditional Actions - An Older Example

The first approach above to setting ``dbkey`` based on tool data tables is
prefered, but an older example using so called "loc files" directly is found
below.

In addition to demonstrating this lower-level direct access of .loc files, it
demonstrates an unconditional action. The second block would not be needed for
most cases - it was required in this tool to handle the specific case of a small
reference file used for functional testing. It says that if the dbkey has been
set to ``equCab2chrM`` (which is what the ``<filter type="metadata_value"...
column="1" />`` tag does), then it should be changed to ``equCab2`` (which is the
``<option type="from_param" ... column="0" ...>`` tag does).

```xml
<actions>
   <conditional name="refGenomeSource.genomeSource">
      <when value="indexed">
           <action type="metadata" name="dbkey">
            <option type="from_file" name="bowtie_indices.loc" column="0" offset="0">
               <filter type="param_value" column="0" value="#" compare="startswith" keep="false"/>
               <filter type="param_value" ref="refGenomeSource.index" column="1"/>
            </option>
         </action>
       </when>
    </conditional>
    <!-- Special casing equCab2chrM to equCab2 -->
    <action type="metadata" name="dbkey">
        <option type="from_param" name="refGenomeSource.genomeSource" column="0" offset="0">
            <filter type="insert_column" column="0" value="equCab2chrM"/>
            <filter type="insert_column" column="0" value="equCab2"/>
            <filter type="metadata_value" ref="output" name="dbkey" column="1" />
        </option>
    </action>
</actions>
```





## ``tool`` > ``outputs`` > ``data`` > ``actions`` > ``conditional``



This directive is contained within an output ``data``'s  ``actions`` directive.
This directive describes the state of the inputs required to apply an ``action``
(specified as children of the child ``when`` directives to this element) to an
output.

See [actions](#tool-outputs-data-actions) documentation for examples
of this directive.




### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | Name of the input parameter to base conditional logic on. The value of this parameter will be matched against nested ``when`` directives. | True


## ``tool`` > ``outputs`` > ``data`` > ``actions`` > ``conditional`` > ``when``



See [actions](#tool-outputs-data-actions) documentation for examples
of this directive.

      


### Attributes

Attribute | Details | Required
--- | --- | ---
``value`` | Value to match conditional input value against. | False
``datatype_isinstance`` | Datatype to match against (if ``value`` is unspecified). This should be the short string describing the format (e.g. ``interval``). | False


## ``tool`` > ``outputs`` > ``data`` > ``actions`` > ``action``



This directive is contained within an output ``data``'s  ``actions`` directive
(either directly or beneath a parent ``conditional`` tag). This directive
describes modifications to either the output's format or metadata (based on
whether ``type`` is ``format`` or ``metadata``).

See [actions](#tool-outputs-data-actions) documentation for examples
of this directive.




### Attributes

Attribute | Details | Required
--- | --- | ---
``type`` | Type of action (either ``format`` or ``metadata`` currently). | True
``name`` | If ``type="metadata"``, the name of the metadata element. | False
``default`` | If ``type="format"``, the default format if none of the nested options apply. | False


## ``tool`` > ``outputs`` > ``data`` > ``discover_datasets``



Describe datasets to dynamically collect after the job complete.

There are many simple tools with examples of this element distributed with
Galaxy, including:

* [multi_output.xml](https://github.com/galaxyproject/galaxy/tree/master/test/functional/tools/multi_output.xml)
* [multi_output_assign_primary.xml](https://github.com/galaxyproject/galaxy/tree/master/test/functional/tools/multi_output_assign_primary.xml)
* [multi_output_configured.xml](https://github.com/galaxyproject/galaxy/tree/master/test/functional/tools/multi_output_configured.xml)

More information can be found on Planemo's documentation for
[multiple output files](https://planemo.readthedocs.io/en/latest/writing_advanced.html#multiple-output-files).



### Attributes

Attribute | Details | Required
--- | --- | ---
``from_provided_metadata`` | Indicate that dataset filenames should simply be read from the provided metadata file (e.g. galaxy.json). If this is set - pattern and sort must not be set. | False
``pattern`` | Regular expression used to find filenames and parse dynamic properties. | False
``directory`` | Directory (relative to working directory) to search for files. | False
``recurse`` | Indicates that the specified directory should be searched recursively for matching files. | False
``match_relative_path`` | Indicates that the entire path of the discovered dataset relative to the specified directory should be available for matching patterns. | False
``format`` | Format (or datatype) of discovered datasets (an alias with ``ext``). | False
``ext`` | Format (or datatype) of discovered datasets (an alias with ``format``). | False
``sort_by`` | A string `[reverse_][SORT_COMP_]SORTBY` describing the desired sort order of the collection elements. `SORTBY` can be `filename`, `name`, `designation`, `dbkey` and the optional `SORT_COMP` can be either `lexical` or `numeric`. Default is lexical sorting by filename. | False
``visible`` | Indication if this dataset is visible in output history. This defaults to ``false``, but probably shouldn't - be sure to set to ``true`` if that is your intention. | False
``assign_primary_output`` | Replace the primary dataset described by the parameter ``data`` parameter with the first output discovered. | False


## ``tool`` > ``outputs`` > ``collection``



This tag set is contained within the ``<outputs>`` tag set, and it defines the
output dataset collection description resulting from the tool's execution. The
value of the attribute ``label`` can be acquired from input parameters or
metadata in the same way that the command line parameters are (discussed in the
[command](#tool-command) directive).

Creating collections in tools is covered in-depth in
[Planemo's documentation](https://planemo.readthedocs.io/en/latest/writing_advanced.html#creating-collections).




### Attributes

Attribute | Details | Required
--- | --- | ---
``type`` | Collection type for output (e.g. ``paired``, ``list``, or ``list:list``). | False
``type_source`` | This is the name of input collection to derive collection's type (e.g. ``collection_type``) from. | False
``format`` | The short name for the output datatype. The valid values for format can be found in [/config/datatypes_conf.xml.sample](https://github.com/galaxyproject/galaxy/blob/dev/config/datatypes_conf.xml.sample) (e.g. ``format="pdf"`` or ``format="fastqsanger"``). For collections this is the default format for all included elements. Note that the format specified here is ignored for discovered data sets. | False
``format_source`` | This sets the data type of the output dataset(s) to be the same format as that of the specified tool input. | False
``label`` | This will be the name of the history item for the output data set. The string can include structure like ``${<some param name>.<some attribute>}``, as discussed for command line parameters in the ``<command>`` tag set section above. The default label is ``${tool.name} on ${on_string}``. | False
``name`` | Name for this output. This ``name`` is used as the Cheetah variable containing the Galaxy assigned output path in ``command`` and ``configfile`` elements. The name should not contain pipes or periods (e.g. ``.``). | True
``structured_like`` | This is the name of input collection or dataset to derive "structure" of the output from (output element count and identifiers). For instance, if the referenced input has three ordered items with identifiers ``sample1``, ``sample2``,  and ``sample3``. If this references input elements in conditionals, this value should be qualified (e.g. ``cond|input`` instead of ``input`` if ``input`` is in a conditional with ``name="cond"``). | False
``inherit_format`` | If ``structured_like`` is set, inherit format of outputs from format of corresponding input. | False


## ``tool`` > ``outputs`` > ``collection`` > ``filter``


The ``<data>`` tag can contain a ``<filter>`` tag which includes a Python code
block to be executed to test whether to include this output in the outputs the
tool ultimately creates. If the code, when executed, returns ``True``,
the output dataset is retained. In these code blocks the tool parameters appear
as Python variables and are thus referred to without the $ used for the Cheetah
template (used in the ``<command>`` tag). Variables that are part of
conditionals are accessed using a dictionary named after the conditional. Boolean
parameters appear as booleans, not the value of their ``truevalue`` and
``falsevalue`` attributes. In the example below, ``options["selection_mode"]`` would
appear as ``$options.selection_mode`` in Cheetah. Similarly ``options["vcf_output"]``
would appear as ``$options.vcf_output`` having the values ``'--vcf'`` when true and
``''`` when false in Cheetah.
Note that also parameters in sections are accessed via a dictionary.

### Example

```xml
    <inputs>
      <param type="data" format="fasta" name="reference_genome" label="Reference genome" />
      <param type="data" format="bam" name="input_bam" label="Aligned reads" />
      <conditional name="options">
        <param label="Use advanced options" name="selection_mode" type="select">
          <option selected="true" value="defaults">Use default options</option>
          <option value="advanced">Use advanced options</option>
        </param>
        <when value="defaults" />
        <when value="advanced">
          <param name="vcf_output" type="boolean" checked="false" label="VCF output"
            truevalue="--vcf" falsevalue="" />
        </when>
      </conditional>
    </inputs>
    <outputs>
      <data format="txt" label="Alignment report on ${on_string}" name="output_txt" />
      <data format="vcf" label="Variant summary on ${on_string}" name="output_vcf">
          <filter>options['selection_mode'] == 'advanced' and options['vcf_output']</filter>
      </data>
    </outputs>
```

Note that variables that correspond to optional select parameters are `None` if nothing is selected. 
Therefore a filter for such a variable looks like the following example.

### Example

```xml
    <inputs>
       <param name="output_type" type="select" optional="true">
            <option value="save_phase">Phase Movie</option>
            <option value="save_period">Period Movie</option>
        </param>
    </inputs>

    <outputs>
        <data name="phase_out" format="tiff">
            <filter>output_type and "save_phase" in output_type</filter>
        </data>
        <data name="period_out" format="tiff" label="${movie.name[:-4]}_period">
            <filter>output_type and "save_period" in output_type</filter>
        </data>
    </outputs>
```





## ``tool`` > ``outputs`` > ``collection`` > ``discover_datasets``



This tag allows one to describe the datasets contained within an output
collection dynamically, such that the outputs are "discovered" based on regular
expressions after the job is complete.

There are many simple tools with examples of this element distributed with
Galaxy, including:

* [collection_split_on_column.xml](https://github.com/galaxyproject/galaxy/blob/master/test/functional/tools/collection_split_on_column.xml)
* [collection_creates_dynamic_list_of_pairs.xml](https://github.com/galaxyproject/galaxy/blob/master/test/functional/tools/collection_creates_dynamic_list_of_pairs.xml)
* [collection_creates_dynamic_nested.xml](https://github.com/galaxyproject/galaxy/blob/master/test/functional/tools/collection_creates_dynamic_nested.xml)




### Attributes

Attribute | Details | Required
--- | --- | ---
``from_provided_metadata`` | Indicate that dataset filenames should simply be read from the provided metadata file (e.g. galaxy.json). If this is set - pattern and sort_by must not be set. | False
``pattern`` | Regular expression used to find filenames and parse dynamic properties. | False
``directory`` | Directory (relative to working directory) to search for files. | False
``recurse`` | Indicates that the specified directory should be searched recursively for matching files. | False
``match_relative_path`` | Indicates that the entire path of the discovered dataset relative to the specified directory should be available for matching patterns. | False
``format`` | Format (or datatype) of discovered datasets (an alias with ``ext``). | False
``ext`` | Format (or datatype) of discovered datasets (an alias with ``format``). | False
``sort_by`` | A string `[reverse_][SORT_COMP_]SORTBY` describing the desired sort order of the collection elements. `SORTBY` can be `filename`, `name`, `designation`, `dbkey` and the optional `SORT_COMP` can be either `lexical` or `numeric`. Default is lexical sorting by filename. | False
``visible`` | Indication if this dataset is visible in the history. This defaults to ``false``, but probably shouldn't - be sure to set to ``true`` if that is your intention. | False


## ``tool`` > ``tests``



Container tag set to specify tests via the ``<test>`` tag sets. Any number of tests can be included,
and each test is wrapped within separate ``<test>`` tag sets. Functional tests are
executed via [Planemo](https://planemo.readthedocs.io/) or the
[run_tests.sh](https://github.com/galaxyproject/galaxy/blob/dev/run_tests.sh)
shell script distributed with Galaxy.

The documentation contained here is mostly reference documentation, for
tutorials on writing tool tests please check out Planemo's
[Test-Driven Development](https://planemo.readthedocs.io/en/latest/writing_advanced.html#test-driven-development)
documentation or the much older wiki content for
[WritingTests](https://galaxyproject.org/admin/tools/writing-tests/).



### Best Practices

Find the Intergalactic Utilities Commision suggested best practices for this
element [here](https://planemo.readthedocs.io/en/latest/standards/docs/best_practices/tool_xml.html#tests).



## ``tool`` > ``tests`` > ``test``



This tag set contains the necessary parameter values for executing the tool via
the functional test framework.

### Example

The following two tests will execute the
[/tools/filters/sorter.xml](https://github.com/galaxyproject/galaxy/blob/dev/tools/filters/sorter.xml)
tool. Notice the way that the tool's inputs and outputs are defined.

```xml
  <tests>
    <test>
      <param name="input" value="1.bed" ftype="bed" />
      <param name="column" value="1"/>
      <param name="order" value="ASC"/>
      <param name="style" value="num"/>
      <output name="out_file1" file="sort1_num.bed" ftype="bed" />
    </test>
    <test>
      <param name="input" value="7.bed" ftype="bed" />
      <param name="column" value="1"/>
      <param name="order" value="ASC"/>
      <param name="style" value="alpha"/>
      <output name="out_file1" file="sort1_alpha.bed" ftype="bed" />
    </test>
  </tests>
```

The following example, tests the execution of the MAF-to-FASTA converter
([/tools/maf/maf_to_fasta.xml](https://github.com/galaxyproject/galaxy/blob/master/tools/maf/maf_to_fasta.xml)).

```xml
<tests>
    <test>
        <param name="input1" value="3.maf" ftype="maf"/>
        <param name="species" value="canFam1"/>
        <param name="fasta_type" value="concatenated"/>
        <output name="out_file1" file="cf_maf2fasta_concat.dat" ftype="fasta"/>
    </test>
</tests>
```

This test demonstrates verifying specific properties about a test output instead
of directly comparing it to another file. Here the file attribute is not
specified and instead a series of assertions is made about the output.

```xml
<test>
    <param name="input" value="maf_stats_interval_in.dat" />
    <param name="lineNum" value="99999"/>
    <output name="out_file1">
        <assert_contents>
            <has_text text="chr7" />
            <not_has_text text="chr8" />
            <has_text_matching expression="1274\d+53" />
            <has_line_matching expression=".*\s+127489808\s+127494553" />
            <!-- &#009; is XML escape code for tab -->
            <has_line line="chr7&#009;127471195&#009;127489808" />
            <has_n_columns n="3" />
            <has_n_lines n="3" />
        </assert_contents>
    </output>
</test>
```




### Attributes

Attribute | Details | Required
--- | --- | ---
``expect_exit_code`` | Describe the job's expected exit code. | False
``expect_num_outputs`` | Assert the number of outputs this test should produce, this is useful to ensure ``filter`` directives are implemented correctly. | False
``expect_failure`` | Setting this to ``true`` indicates the expectation is for the job fail. If set to ``true`` no job output checks may be present in ``test`` definition. | False
``maxseconds`` | Maximum amount of time to let test run. | False


## ``tool`` > ``tests`` > ``test`` > ``param``



This tag set defines the tool's input parameters for executing the tool via the
functional test framework. See [test](#tool-tests-test) documentation for
some simple examples of parameters.

### Parameter Types

#### ``text``, ``integer``, and ``float``

Values for these parameters are simply given by the desired value.

#### ``boolean``

The value of the test parameter should be set to `true` or `false` corresponding
to the cases that the parameter is checked or not. Alternatively the value
specified as `truevalue` or `falsevalue` can be given.

#### ``data``

Data input parameters can be given as a file name. The file should exist in the
`test-data` folder. Multiple files can be specified as comma separated list.

#### ``select``

The value of a select parameter should be specified as the value of one of the
legal options. If more than one option is selected (`multiple="true"`) they
should be given as comma separated list. For optional selects
(`optional="true"`) the case that no option is selected can be specified with
`value=""`.

While in general it is preferred to specify the selected cases by their values it
is also possible to specify them by their name (i.e. the content of the
`option` tag that is shown to the user). One use case is a dynamic select that is
generated from a data table with two columns: name and value where the value is
a path. Since the path changes with the test environment it can not be used to
select an option for a test.




### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | This value must match the name of the associated input parameter (``param``). | True
``value`` | This value must be one of the legal values that can be assigned to an input parameter. | False
``value_json`` | This variant of the value parameters can be used to load typed parameters. This string will be loaded as JSON and its type will attempt to be preserved through API requests to Galaxy. | False
``ftype`` | This attribute name should be included only with parameters of ``type`` ``data`` for the tool. If this attribute name is not included, the functional test framework will attempt to determine the data type for the input dataset using the data type sniffers. | False
``dbkey`` | Specifies a ``dbkey`` value for the referenced input dataset. This is only valid if the corresponding parameter is of ``type`` ``data``. | False
``tags`` | Comma separated list of tags to apply to the dataset (only works for elements of collections - e.g. ``element`` XML tags). | False


## ``tool`` > ``tests`` > ``test`` > ``param`` > ``collection``

Definition of a collection for test input.


### Attributes

Attribute | Details | Required
--- | --- | ---
``type`` | Type of collection to create. | True
``tags`` | Comma separated list of tags to apply to the dataset (only works for elements of collections - e.g. ``element`` XML tags). | False


## ``tool`` > ``tests`` > ``test`` > ``repeat``



Specify test parameters below an iteration of a ``repeat`` block with this
element.

``param`` elements in a ``test`` block can be arranged into nested ``repeat``,
``conditional``, and ``select`` structures to match the inputs. While this might
be overkill for simple tests, it helps prevent ambiguous definitions and keeps
things organized in large test cases. A future ``profile`` version of Galaxy
tools may require ``repeat`` blocks be explicitly defined with this directive.

### Examples

The test tool [disambiguate_repeats.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/disambiguate_repeats.xml)
demonstrates the use of this directive.

This first test case demonstrates that this block allows different values for
the ``param`` named ``input`` to be tested even though this parameter name
appears in two different ``<repeat>`` elements in the ``<inputs>`` definition.

```xml
<!-- Can disambiguate repeats and specify multiple blocks using,
     nested structure. -->
<test>
    <repeat name="queries">
        <param name="input" value="simple_line.txt"/>
    </repeat>
    <repeat name="more_queries">
        <param name="input" value="simple_line_alternative.txt"/>
    </repeat>
    <output name="out_file1">
        <assert_contents>
            <has_line line="This is a line of text." />
            <has_line line="This is a different line of text." />
        </assert_contents>
    </output>
</test>
```

The second definition in that file demonstrates repeated ``<repeat>`` blocks
allowing multiple instances of a single repeat to be specified.

```xml
<!-- Multiple such blocks can be specified but only with newer API
     driven tests. -->
<test>
    <repeat name="queries">
        <param name="input" value="simple_line.txt"/>
    </repeat>
    <repeat name="queries">
        <param name="input" value="simple_line_alternative.txt"/>
    </repeat>
    <repeat name="more_queries">
        <param name="input" value="simple_line.txt"/>
    </repeat>
    <repeat name="more_queries">
        <param name="input" value="simple_line_alternative.txt"/>
    </repeat>
    <output name="out_file1" file="simple_lines_interleaved.txt"/>
</test>
```




### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | This value must match the name of the associated input ``repeat``. | True


## ``tool`` > ``tests`` > ``test`` > ``section``



Specify test parameters below a named of a ``section`` block matching
one in ``inputs`` with this element.

``param`` elements in a ``test`` block can be arranged into nested ``repeat``,
``conditional``, and ``select`` structures to match the inputs. While this might
be overkill for simple tests, it helps prevent ambiguous definitions and keeps
things organized in large test cases. A future ``profile`` version of Galaxy
tools may require ``section`` blocks be explicitly defined with this
directive.

### Examples

The test tool demonstrating sections
([section.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/section.xml))
contains a test case demonstrating this block. This test case appears below:

```xml
<test>
    <section name="int">
        <param name="inttest" value="12456" />
    </section>
    <section name="float">
        <param name="floattest" value="6.789" />
    </section>
    <output name="out_file1">
        <assert_contents>
            <has_line line="12456" />
            <has_line line="6.789" />
        </assert_contents>
    </output>
</test>
```


      


### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | This value must match the name of the associated input ``section``. | True


## ``tool`` > ``tests`` > ``test`` > ``conditional``



Specify test parameters below a named of a ``conditional`` block matching
one in ``inputs`` with this element.

``param`` elements in a ``test`` block can be arranged into nested ``repeat``,
``conditional``, and ``select`` structures to match the inputs. While this might
be overkill for simple tests, it helps prevent ambiguous definitions and keeps
things organized in large test cases. A future ``profile`` version of Galaxy
tools may require ``conditional`` blocks be explicitly defined with this
directive.

### Examples

The following example demonstrates disambiguation of a parameter (named ``use``)
which appears in multiple ``param`` names in ``conditional``s in the ``inputs``
definition of the [disambiguate_cond.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/disambiguate_cond.xml)
tool.

```xml
<!-- Can use nested conditional blocks as shown below to disambiguate
     various nested parameters. -->
<test>
    <conditional name="p1">
        <param name="use" value="False"/>
    </conditional>
    <conditional name="p2">
        <param name="use" value="True"/>
    </conditional>
    <conditional name="p3">
        <param name="use" value="False"/>
    </conditional>
    <conditional name="files">
        <param name="attach_files" value="True" />
        <conditional name="p4">
            <param name="use" value="True"/>
            <param name="file" value="simple_line_alternative.txt" />
        </conditional>
    </conditional>
    <output name="out_file1">
        <assert_contents>
            <has_line line="7 4 7" />
            <has_line line="This is a different line of text." />
        </assert_contents>
    </output>
</test>
```

The [tophat2](https://github.com/galaxyproject/tools-devteam/blob/master/tools/tophat2/tophat2_wrapper.xml)
tool demonstrates a real tool that benefits from more structured test cases
using the ``conditional`` test directive. One such test case from that tool is
shown below.

```xml
<!-- Test base-space paired-end reads with user-supplied reference fasta and full parameters -->
<test>
    <!-- TopHat commands:
    tophat2 -o tmp_dir -r 20 -p 1 -a 8 -m 0 -i 70 -I 500000 -g 40 +coverage-search +min-coverage-intron 50 +max-coverage-intro 20000 +segment-mismatches 2 +segment-length 25 +microexon-search +report_discordant_pairs tophat_in1 test-data/tophat_in2.fastqsanger test-data/tophat_in3.fastqsanger
    Replace the + with double-dash
    Rename the files in tmp_dir appropriately
    -->
    <conditional name="singlePaired">
      <param name="sPaired" value="paired"/>
      <param name="input1" ftype="fastqsanger" value="tophat_in2.fastqsanger"/>
      <param name="input2" ftype="fastqsanger" value="tophat_in3.fastqsanger"/>
      <param name="mate_inner_distance" value="20"/>
      <param name="report_discordant_pairs" value="Yes" />
    </conditional>
    <param name="genomeSource" value="indexed"/>
    <param name="index" value="tophat_test"/>
    <conditional name="params">
      <param name="settingsType" value="full"/>
      <param name="library_type" value="FR Unstranded"/>
      <param name="read_mismatches" value="5"/>
      <!-- Error: the read mismatches (5) and the read gap length (2) should be less than or equal to the read edit dist (2) -->
      <param name="read_edit_dist" value="5" />
      <param name="bowtie_n" value="Yes"/>
      <param name="mate_std_dev" value="20"/>
      <param name="anchor_length" value="8"/>
      <param name="splice_mismatches" value="0"/>
      <param name="min_intron_length" value="70"/>
      <param name="max_intron_length" value="500000"/>
      <param name="max_multihits" value="40"/>
      <param name="min_segment_intron" value="50" />
      <param name="max_segment_intron" value="500000" />
      <param name="seg_mismatches" value="2"/>
      <param name="seg_length" value="25"/>
      <conditional name="indel_search">
        <param name="allow_indel_search" value="No"/>
      </conditional>
      <conditional name="own_junctions">
        <param name="use_junctions" value="Yes" />
        <conditional name="gene_model_ann">
          <param name="use_annotations" value="No" />
        </conditional>
        <conditional name="raw_juncs">
          <param name="use_juncs" value="No" />
        </conditional>
        <conditional name="no_novel_juncs">
          <param name="no_novel_juncs" value="No" />
        </conditional>
      </conditional>
      <conditional name="coverage_search">
        <param name="use_search" value="No" />
      </conditional>
      <param name="microexon_search" value="Yes" />
      <conditional name="bowtie2_settings">
        <param name="b2_settings" value="No" />
      </conditional>
      <!-- Fusion search params -->
      <conditional name="fusion_search">
        <param name="do_search" value="Yes" />
        <param name="anchor_len" value="21" />
        <param name="min_dist" value="10000021" />
        <param name="read_mismatches" value="3" />
        <param name="multireads" value="4" />
        <param name="multipairs" value="5" />
        <param name="ignore_chromosomes" value="chrM"/>
      </conditional>
    </conditional>
    <conditional name="readGroup">
      <param name="specReadGroup" value="no" />
    </conditional>
    <output name="junctions" file="tophat2_out4j.bed" />
    <output name="accepted_hits" file="tophat_out4h.bam" compare="sim_size" />
</test>
```




### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | This value must match the name of the associated input ``conditional``. | True


## ``tool`` > ``tests`` > ``test`` > ``output``



This tag set defines the variable that names the output dataset for the
functional test framework. The functional test framework will execute the tool
using the parameters defined in the ``<param>`` tag sets and generate a
temporary file, which will either be compared with the file named in the
``file`` attribute value or checked against assertions made by a child
``assert_contents`` tag to verify that the tool is functionally correct.

        


### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | This value is the same as the value of the ``name`` attribute of the ``<data>`` tag set contained within the tool's ``<outputs>`` tag set. | False
``file`` | If specified, this value is the name of the output file stored in the target ``test-data`` directory which will be used to compare the results of executing the tool via the functional test framework. | False
``value_json`` | If specified, this value will be loaded as JSON and compared against the output generated as JSON. This can be useful for testing tool outputs that are not files. | False
``ftype`` | If specified, this value will be checked against the corresponding output's data type. If these do not match, the test will fail. | False
``sort`` | This flag causes the lines of the output to be sorted before they are compared to the expected output. This could be useful for non-deterministic output. | False
``value`` | An alias for ``file``. | False
``md5`` | If specified, the target output's MD5 hash should match the value specified here. For large static files it may be inconvenient to upload the entiry file and this can be used instead. | False
``checksum`` | If specified, the target output's checksum should match the value specified here. This value should have the form ``hash_type$hash_value`` (e.g. ``sha1$8156d7ca0f46ed7abac98f82e36cfaddb2aca041``). For large static files it may be inconvenient to upload the entiry file and this can be used instead. | False
``compare`` | Type of comparison to use when comparing test generated output files to expected output files. Currently valid value are ``diff`` (the default), ``re_match``, ``sim_size``, ``re_match_multiline``, and ``contains``. | False
``lines_diff`` | If ``compare`` is set to ``diff``, the number of lines of difference to allow (each line with a modification is a line added and a line removed so this counts as two lines). | False
``decompress`` | When this attribute is true and ``compare`` is set to ``diff``, try to decompress files if needed. This flag is useful for testing compressed outputs that are non-deterministic despite having deterministic decompressed contents. By default, only files compressed with bz2, gzip and zip will be automatically decompressed. This is available in Galaxy since release 17.05 and was introduced in [pull request #3550](https://github.com/galaxyproject/galaxy/pull/3550). | False
``delta`` | If ``compare`` is set to ``sim_size``, this is the maximum allowed absolute size difference (in bytes) between the data set that is generated in the test and the file in ``test-data/`` that is referenced by the ``file`` attribute. Default value is 10000 bytes. Can be combined with ``delta_frac``. | False
``delta_frac`` | If ``compare`` is set to ``sim_size``, this is the maximum allowed relative size difference between the data set that is generated in the test and the file in ``test-data/`` that is referenced by the ``file`` attribute. A value of 0.1 means that the file that is generated in the test can differ by at most 10% of the file in ``test-data``. The default is not to check for  relative size difference. Can be combined with ``delta``. | False


## ``tool`` > ``tests`` > ``test`` > ``output`` > ``discover_dataset``



This directive specifies a test for an output's discovered dataset. It acts as an
``output`` test tag in many ways and can define any tests of that tag (e.g.
``assert_contents``, ``value``, ``compare``, ``md5``, ``checksum``, ``metadata``, etc...).

### Example

The functional test tool
[multi_output_assign_primary.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/multi_output_assign_primary.xml)
provides a demonstration of using this tag.

```xml
<outputs>
    <data format="tabular" name="sample">
      <discover_datasets pattern="(?P&lt;designation&gt;.+)\.report\.tsv" ext="tabular" visible="true" assign_primary_output="true" />
    </data>
</outputs>
<test>
  <param name="num_param" value="7" />
  <param name="input" ftype="txt" value="simple_line.txt"/>
  <output name="sample">
    <assert_contents>
      <has_line line="1" />
    </assert_contents>
    <!-- no sample1 it was consumed by named output "sample" -->
    <discovered_dataset designation="sample2" ftype="tabular">
      <assert_contents><has_line line="2" /></assert_contents>
    </discovered_dataset>
    <discovered_dataset designation="sample3" ftype="tabular">
      <assert_contents><has_line line="3" /></assert_contents>
    </discovered_dataset>
  </output>
</test>
```

Note that this tool uses ``assign_primary_output="true"`` for ``<discover_data_sets>``. Hence, the content of the first discovered dataset (which is the first in the alphabetically sorted list of discovered designations) is checked directly in the ``<output>`` tag of the test.



### Attributes

Attribute | Details | Required
--- | --- | ---
``designation`` | The designation of the discovered dataset. | False


## ``tool`` > ``tests`` > ``test`` > ``output`` > ``metadata``



This directive specifies a test for an output's metadata as an expected key-value pair.

### Example

The functional test tool
[tool_provided_metadata_1.xml](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/tool_provided_metadata_1.xml)
provides a demonstration of using this tag.

```xml
<test>
  <param name="input1" value="simple_line.txt" />
  <output name="out1" file="simple_line.txt" ftype="txt">
    <metadata name="name" value="my dynamic name" />
    <metadata name="info" value="my dynamic info" />
    <metadata name="dbkey" value="cust1" />
  </output>
</test>
```




### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | Name of the metadata element to check. | True
``value`` | Expected value (as a string) of metadata value. | True


## ``tool`` > ``tests`` > ``test`` > ``output`` > ``assert_contents``



This tag set defines a sequence of checks or assertions to run against the
target output. This tag requires no attributes, but child tags should be used to
define the assertions to make about the output. The functional test framework
makes it easy to extend Galaxy with such tags, the following table summarizes
many of the default assertion tags that come with Galaxy and examples of each
can be found below.

The implementation of these tags are simply Python functions defined in the
[/lib/galaxy/tool_util/verify/asserts](https://github.com/galaxyproject/galaxy/tree/dev/lib/galaxy/tool_util/verify/asserts)
module.

      

Child Element/Assertion | Details 
--- | ---
``has_text`` | Asserts the specified ``text`` appears in the output (e.g. ``<has_text text="chr7">``). If the ``text`` is expected to occur a particular number of times, this value can be specified using ``n``.
``not_has_text`` | Asserts the specified ``text`` does not appear in the output (e.g. ``<not_has_text text="chr8" />``).
``has_text_matching`` | Asserts text matching the specified regular expression (``expression``) appears in the output (e.g. ``<has_text_matching expression="1274\d+53" />`` ).
``has_line`` | Asserts a line matching the specified string (``line``) appears in the output (e.g. ``<has_line line="A full example line." />``). If the ``line`` is expected to occur a particular number of times, this value can be specified using ``n``.
``has_n_lines`` | Asserts that an output contains ``n`` lines, e.g. ``<has_n_lines n="3" />``.
``has_line_matching`` | Asserts a line matching the specified regular expression (``expression``) appears in the output (e.g. ``<has_line_matching expression=".*\s+127489808\s+127494553" />``).
``has_n_columns`` | Asserts tabular output contains the specified number (``n``) of columns (e.g. ``<has_n_columns n="3" />``).
``is_valid_xml`` | Asserts the output is a valid XML file (e.g. ``<is_valid_xml />``).
``has_element_with_path`` | Asserts the XML output contains at least one element (or tag) with the specified XPath-like ``path`` (e.g. ``<has_element_with_path path="BlastOutput_param/Parameters/Parameters_matrix" />``).
``has_n_elements_with_path`` | Asserts the XML output contains the specified number (``n``) of elements (or tags) with the specified XPath-like ``path`` (e.g. ``<has_n_elements_with_path n="9" path="BlastOutput_iterations/Iteration/Iteration_hits/Hit/Hit_num" />``).
``element_text_is`` | Asserts the text of the XML element with the specified XPath-like ``path`` is the specified ``text`` (e.g. ``<element_text_is path="BlastOutput_program" text="blastp" />``).
``element_text_matches`` | Asserts the text of the XML element with the specified XPath-like ``path`` matches the regular expression defined by ``expression`` (e.g. ``<element_text_matches path="BlastOutput_version" expression="BLASTP\s+2\.2.*" />``).
``attribute_is`` | Asserts the XML ``attribute`` for the element (or tag) with the specified XPath-like ``path`` is the specified ``text`` (e.g. ``<attribute_is path="outerElement/innerElement1" attribute="foo" text="bar" />`` ).
``attribute_matches`` | Asserts the XML ``attribute`` for the element (or tag) with the specified XPath-like ``path`` matches the regular expression specified by ``expression`` (e.g. ``<attribute_matches path="outerElement/innerElement2" attribute="foo2" expression="bar\d+" />``).
``element_text`` | This tag allows the developer to recurisively specify additional assertions as child elements about just the text contained in the element specified by the XPath-like ``path`` (e.g. ``<element_text path="BlastOutput_iterations/Iteration/Iteration_hits/Hit/Hit_def"><not_has_text text="EDK72998.1" /></element_text>``).
``has_h5_keys`` | Asserts HDF5 output has a set of attributes (``keys``), specified as a comma-separated list (e.g. ``<has_h5_keys keys="bins,chroms,indexes,pixels,chroms/lengths" />``).
``has_h5_attribute`` | Asserts HDF5 output contains the specified ``value`` for an attribute (``key``) (e.g. ``<has_attr key="nchroms" value="15" />``).
``has_archive_member`` | This tag allows the developer to recursively specify additional assertions as child elements about just the member contained in the archive specified by the regular expression ``path`` (e.g. ``<has_archive_member path=".*/my-file.txt"><not_has_text text="EDK72998.1" /></has_archive_member>``). Valid archive formats include ``.zip``, ``.tar``, and ``.tar.gz``.
``has_size`` | Asserts the output has specific size (in bytes), e.g. ``<has_size value="10000" delta="100" />``.


### Examples

The following demonstrates a wide variety of text-based and tabular
assertion statements.

```xml
<output name="out_file1">
    <assert_contents>
        <has_text text="chr7" />
        <not_has_text text="chr8" />
        <has_text_matching expression="1274\d+53" />
        <has_line_matching expression=".*\s+127489808\s+127494553" />
        <!-- &#009; is XML escape code for tab -->
        <has_line line="chr7&#009;127471195&#009;127489808" />
        <has_n_columns n="3" />
    </assert_contents>
</output>
```

The following demonstrates a wide variety of XML assertion statements.

```xml
<output name="out_file1">
    <assert_contents>
        <is_valid_xml />
        <has_element_with_path path="BlastOutput_param/Parameters/Parameters_matrix" />
        <has_n_elements_with_path n="9" path="BlastOutput_iterations/Iteration/Iteration_hits/Hit/Hit_num" />
        <element_text_matches path="BlastOutput_version" expression="BLASTP\s+2\.2.*" />
        <element_text_is path="BlastOutput_program" text="blastp" />
        <element_text path="BlastOutput_iterations/Iteration/Iteration_hits/Hit/Hit_def">
            <not_has_text text="EDK72998.1" />
            <has_text_matching expression="ABK[\d\.]+" />
        </element_text>
    </assert_contents>
</output>
```

The following demonstrates verifying XML content with XPath-like expressions.

```xml
<output name="out_file1">
    <assert_contents>
        <attribute_is path="outerElement/innerElement1" attribute="foo" text="bar" />
        <attribute_matches path="outerElement/innerElement2" attribute="foo2" expression="bar\d+" />
    </assert_contents>
</output>
```





## ``tool`` > ``tests`` > ``test`` > ``output_collection``



Define tests for extra datasets and metadata corresponding to an output collection.

``output_collection`` directives should specify a ``name`` and ``type``
attribute to describe the expected output collection as a whole.

Expectations about collection contents are described using child ``element``
directives. For nested collections, these child ``element`` directives may
themselves contain children.

For tools marked as having profile 20.09 or newer, the order of elements within
an ``output_collection`` declaration are meaningful. The test definition may
omit any number of elements from a collection, but the ones that are specified
will be checked against the actual resulting collection from the tool run and the
order within the collection verified.

### Examples

The [genetrack](https://github.com/galaxyproject/tools-iuc/blob/master/tools/genetrack/genetrack.xml)
tool demonstrates basic usage of an ``output_collection`` test expectation.

```xml
<test>
    <param name="input" value="genetrack_input2.gff" ftype="gff" />
    <param name="input_format" value="gff" />
    <param name="sigma" value="5" />
    <param name="exclusion" value="20" />
    <param name="up_width" value="10" />
    <param name="down_width" value="10" />
    <param name="filter" value="3" />
    <output_collection name="genetrack_output" type="list">
        <element name="s5e20u10d10F3_on_data_1" file="genetrack_output2.gff" ftype="gff" />
    </output_collection>
</test>
```

The [CWPair2](https://github.com/galaxyproject/tools-iuc/blob/master/tools/cwpair2/cwpair2.xml)
tool demonstrates that ``element``s can specify a ``compare`` attribute just
like [output](#tool-tests-test-output).

```xml
<test>
    <param name="input" value="cwpair2_input1.gff" />
    <param name="up_distance" value="25" />
    <param name="down_distance" value="100" />
    <param name="method" value="all" />
    <param name="binsize" value="1" />
    <param name="threshold_format" value="relative_threshold" />
    <param name="relative_threshold" value="0.0" />
    <param name="output_files" value="matched_pair" />
    <output name="statistics_output" file="statistics1.tabular" ftype="tabular" />
    <output_collection name="MP" type="list">
        <element name="data_MP_closest_f0u25d100_on_data_1.gff" file="closest_mp_output1.gff" ftype="gff" compare="contains"/>
        <element name="data_MP_largest_f0u25d100_on_data_1.gff" file="largest_mp_output1.gff" ftype="gff" compare="contains"/>
        <element name="data_MP_mode_f0u25d100_on_data_1.gff" file="mode_mp_output1.gff" ftype="gff" compare="contains"/>
    </output_collection>
</test>
```

The
[collection_creates_dynamic_nested](https://github.com/galaxyproject/galaxy/blob/dev/test/functional/tools/collection_creates_dynamic_nested.xml)
test tool demonstrates the use of nested ``element`` directives as described
above. Notice also that it tests the output with ``assert_contents`` instead of
supplying a ``file`` attribute. Like hinted at with with ``compare`` attribute
above, the ``element`` tag can specify any of the test attributes that apply to
the [output](#tool-tests-test-output) (e.g. ``md5``, ``compare``, ``diff``,
etc...).

```xml
<test>
  <param name="foo" value="bar" />
  <output_collection name="list_output" type="list:list">
    <element name="oe1">
      <element name="ie1">
        <assert_contents>
          <has_text_matching expression="^A\n$" />
        </assert_contents>
      </element>
      <element name="ie2">
        <assert_contents>
          <has_text_matching expression="^B\n$" />
        </assert_contents>
      </element>
    </element>
    <element name="oe2">
      <element name="ie1">
        <assert_contents>
          <has_text_matching expression="^C\n$" />
        </assert_contents>
      </element>
      <element name="ie2">
        <assert_contents>
          <has_text_matching expression="^D\n$" />
        </assert_contents>
      </element>
    </element>
    <element name="oe3">
      <element name="ie1">
        <assert_contents>
          <has_text_matching expression="^E\n$" />
        </assert_contents>
      </element>
      <element name="ie2">
        <assert_contents>
          <has_text_matching expression="^F\n$" />
        </assert_contents>
      </element>
    </element>
  </output_collection>
</test>
```




### Attributes

Attribute | Details | Required
--- | --- | ---
``name`` | This value is the same as the value of the ``name`` attribute of the ``<collection>`` tag set contained within the tool's ``<outputs>`` tag set. | True
``type`` | Expected collection type (e.g. ``list``, ``paired``, or ``list:paired``). | False
``count`` | Number of elements in output collection. | False


## ``tool`` > ``tests`` > ``test`` > ``assert_command``

Describe assertions about the job's
generated command-line.


This tag set defines a sequence of checks or assertions to run against the
target output. This tag requires no attributes, but child tags should be used to
define the assertions to make about the output. The functional test framework
makes it easy to extend Galaxy with such tags, the following table summarizes
many of the default assertion tags that come with Galaxy and examples of each
can be found below.

The implementation of these tags are simply Python functions defined in the
[/lib/galaxy/tool_util/verify/asserts](https://github.com/galaxyproject/galaxy/tree/dev/lib/galaxy/tool_util/verify/asserts)
module.

      

Child Element/Assertion | Details 
--- | ---
``has_text`` | Asserts the specified ``text`` appears in the output (e.g. ``<has_text text="chr7">``). If the ``text`` is expected to occur a particular number of times, this value can be specified using ``n``.
``not_has_text`` | Asserts the specified ``text`` does not appear in the output (e.g. ``<not_has_text text="chr8" />``).
``has_text_matching`` | Asserts text matching the specified regular expression (``expression``) appears in the output (e.g. ``<has_text_matching expression="1274\d+53" />`` ).
``has_line`` | Asserts a line matching the specified string (``line``) appears in the output (e.g. ``<has_line line="A full example line." />``). If the ``line`` is expected to occur a particular number of times, this value can be specified using ``n``.
``has_n_lines`` | Asserts that an output contains ``n`` lines, e.g. ``<has_n_lines n="3" />``.
``has_line_matching`` | Asserts a line matching the specified regular expression (``expression``) appears in the output (e.g. ``<has_line_matching expression=".*\s+127489808\s+127494553" />``).
``has_n_columns`` | Asserts tabular output contains the specified number (``n``) of columns (e.g. ``<has_n_columns n="3" />``).
``is_valid_xml`` | Asserts the output is a valid XML file (e.g. ``<is_valid_xml />``).
``has_element_with_path`` | Asserts the XML output contains at least one element (or tag) with the specified XPath-like ``path`` (e.g. ``<has_element_with_path path="BlastOutput_param/Parameters/Parameters_matrix" />``).
``has_n_elements_with_path`` | Asserts the XML output contains the specified number (``n``) of elements (or tags) with the specified XPath-like ``path`` (e.g. ``<has_n_elements_with_path n="9" path="BlastOutput_iterations/Iteration/Iteration_hits/Hit/Hit_num" />``).
``element_text_is`` | Asserts the text of the XML element with the specified XPath-like ``path`` is the specified ``text`` (e.g. ``<element_text_is path="BlastOutput_program" text="blastp" />``).
``element_text_matches`` | Asserts the text of the XML element with the specified XPath-like ``path`` matches the regular expression defined by ``expression`` (e.g. ``<element_text_matches path="BlastOutput_version" expression="BLASTP\s+2\.2.*" />``).
``attribute_is`` | Asserts the XML ``attribute`` for the element (or tag) with the specified XPath-like ``path`` is the specified ``text`` (e.g. ``<attribute_is path="outerElement/innerElement1" attribute="foo" text="bar" />`` ).
``attribute_matches`` | Asserts the XML ``attribute`` for the element (or tag) with the specified XPath-like ``path`` matches the regular expression specified by ``expression`` (e.g. ``<attribute_matches path="outerElement/innerElement2" attribute="foo2" expression="bar\d+" />``).
``element_text`` | This tag allows the developer to recurisively specify additional assertions as child elements about just the text contained in the element specified by the XPath-like ``path`` (e.g. ``<element_text path="BlastOutput_iterations/Iteration/Iteration_hits/Hit/Hit_def"><not_has_text text="EDK72998.1" /></element_text>``).
``has_h5_keys`` | Asserts HDF5 output has a set of attributes (``keys``), specified as a comma-separated list (e.g. ``<has_h5_keys keys="bins,chroms,indexes,pixels,chroms/lengths" />``).
``has_h5_attribute`` | Asserts HDF5 output contains the specified ``value`` for an attribute (``key``) (e.g. ``<has_attr key="nchroms" value="15" />``).
``has_archive_member`` | This tag allows the developer to recursively specify additional assertions as child elements about just the member contained in the archive specified by the regular expression ``path`` (e.g. ``<has_archive_member path=".*/my-file.txt"><not_has_text text="EDK72998.1" /></has_archive_member>``). Valid archive formats include ``.zip``, ``.tar``, and ``.tar.gz``.
``has_size`` | Asserts the output has specific size (in bytes), e.g. ``<has_size value="10000" delta="100" />``.





## ``tool`` > ``tests`` > ``test`` > ``assert_stdout``

Describe assertions about the job's
standard output.


This tag set defines a sequence of checks or assertions to run against the
target output. This tag requires no attributes, but child tags should be used to
define the assertions to make about the output. The functional test framework
makes it easy to extend Galaxy with such tags, the following table summarizes
many of the default assertion tags that come with Galaxy and examples of each
can be found below.

The implementation of these tags are simply Python functions defined in the
[/lib/galaxy/tool_util/verify/asserts](https://github.com/galaxyproject/galaxy/tree/dev/lib/galaxy/tool_util/verify/asserts)
module.

      

Child Element/Assertion | Details 
--- | ---
``has_text`` | Asserts the specified ``text`` appears in the output (e.g. ``<has_text text="chr7">``). If the ``text`` is expected to occur a particular number of times, this value can be specified using ``n``.
``not_has_text`` | Asserts the specified ``text`` does not appear in the output (e.g. ``<not_has_text text="chr8" />``).
``has_text_matching`` | Asserts text matching the specified regular expression (``expression``) appears in the output (e.g. ``<has_text_matching expression="1274\d+53" />`` ).
``has_line`` | Asserts a line matching the specified string (``line``) appears in the output (e.g. ``<has_line line="A full example line." />``). If the ``line`` is expected to occur a particular number of times, this value can be specified using ``n``.
``has_n_lines`` | Asserts that an output contains ``n`` lines, e.g. ``<has_n_lines n="3" />``.
``has_line_matching`` | Asserts a line matching the specified regular expression (``expression``) appears in the output (e.g. ``<has_line_matching expression=".*\s+127489808\s+127494553" />``).
``has_n_columns`` | Asserts tabular output contains the specified number (``n``) of columns (e.g. ``<has_n_columns n="3" />``).
``is_valid_xml`` | Asserts the output is a valid XML file (e.g. ``<is_valid_xml />``).
``has_element_with_path`` | Asserts the XML output contains at least one element (or tag) with the specified XPath-like ``path`` (e.g. ``<has_element_with_path path="BlastOutput_param/Parameters/Parameters_matrix" />``).
``has_n_elements_with_path`` | Asserts the XML output contains the specified number (``n``) of elements (or tags) with the specified XPath-like ``path`` (e.g. ``<has_n_elements_with_path n="9" path="BlastOutput_iterations/Iteration/Iteration_hits/Hit/Hit_num" />``).
``element_text_is`` | Asserts the text of the XML element with the specified XPath-like ``path`` is the specified ``text`` (e.g. ``<element_text_is path="BlastOutput_program" text="blastp" />``).
``element_text_matches`` | Asserts the text of the XML element with the specified XPath-like ``path`` matches the regular expression defined by ``expression`` (e.g. ``<element_text_matches path="BlastOutput_version" expression="BLASTP\s+2\.2.*" />``).
``attribute_is`` | Asserts the XML ``attribute`` for the element (or tag) with the specified XPath-like ``path`` is the specified ``text`` (e.g. ``<attribute_is path="outerElement/innerElement1" attribute="foo" text="bar" />`` ).
``attribute_matches`` | Asserts the XML ``attribute`` for the element (or tag) with the specified XPath-like ``path`` matches the regular expression specified by ``expression`` (e.g. ``<attribute_matches path="outerElement/innerElement2" attribute="foo2" expression="bar\d+" />``).
``element_text`` | This tag allows the developer to recurisively specify additional assertions as child elements about just the text contained in the element specified by the XPath-like ``path`` (e.g. ``<element_text path="BlastOutput_iterations/Iteration/Iteration_hits/Hit/Hit_def"><not_has_text text="EDK72998.1" /></element_text>``).
``has_h5_keys`` | Asserts HDF5 output has a set of attributes (``keys``), specified as a comma-separated list (e.g. ``<has_h5_keys keys="bins,chroms,indexes,pixels,chroms/lengths" />``).
``has_h5_attribute`` | Asserts HDF5 output contains the specified ``value`` for an attribute (``key``) (e.g. ``<has_attr key="nchroms" value="15" />``).
``has_archive_member`` | This tag allows the developer to recursively specify additional assertions as child elements about just the member contained in the archive specified by the regular expression ``path`` (e.g. ``<has_archive_member path=".*/my-file.txt"><not_has_text text="EDK72998.1" /></has_archive_member>``). Valid archive formats include ``.zip``, ``.tar``, and ``.tar.gz``.
``has_size`` | Asserts the output has specific size (in bytes), e.g. ``<has_size value="10000" delta="100" />``.





## ``tool`` > ``tests`` > ``test`` > ``assert_stderr``

Describe assertions about the job's
standard error.


This tag set defines a sequence of checks or assertions to run against the
target output. This tag requires no attributes, but child tags should be used to
define the assertions to make about the output. The functional test framework
makes it easy to extend Galaxy with such tags, the following table summarizes
many of the default assertion tags that come with Galaxy and examples of each
can be found below.

The implementation of these tags are simply Python functions defined in the
[/lib/galaxy/tool_util/verify/asserts](https://github.com/galaxyproject/galaxy/tree/dev/lib/galaxy/tool_util/verify/asserts)
module.

      

Child Element/Assertion | Details 
--- | ---
``has_text`` | Asserts the specified ``text`` appears in the output (e.g. ``<has_text text="chr7">``). If the ``text`` is expected to occur a particular number of times, this value can be specified using ``n``.
``not_has_text`` | Asserts the specified ``text`` does not appear in the output (e.g. ``<not_has_text text="chr8" />``).
``has_text_matching`` | Asserts text matching the specified regular expression (``expression``) appears in the output (e.g. ``<has_text_matching expression="1274\d+53" />`` ).
``has_line`` | Asserts a line matching the specified string (``line``) appears in the output (e.g. ``<has_line line="A full example line." />``). If the ``line`` is expected to occur a particular number of times, this value can be specified using ``n``.
``has_n_lines`` | Asserts that an output contains ``n`` lines, e.g. ``<has_n_lines n="3" />``.
``has_line_matching`` | Asserts a line matching the specified regular expression (``expression``) appears in the output (e.g. ``<has_line_matching expression=".*\s+127489808\s+127494553" />``).
``has_n_columns`` | Asserts tabular output contains the specified number (``n``) of columns (e.g. ``<has_n_columns n="3" />``).
``is_valid_xml`` | Asserts the output is a valid XML file (e.g. ``<is_valid_xml />``).
``has_element_with_path`` | Asserts the XML output contains at least one element (or tag) with the specified XPath-like ``path`` (e.g. ``<has_element_with_path path="BlastOutput_param/Parameters/Parameters_matrix" />``).
``has_n_elements_with_path`` | Asserts the XML output contains the specified number (``n``) of elements (or tags) with the specified XPath-like ``path`` (e.g. ``<has_n_elements_with_path n="9" path="BlastOutput_iterations/Iteration/Iteration_hits/Hit/Hit_num" />``).
``element_text_is`` | Asserts the text of the XML element with the specified XPath-like ``path`` is the specified ``text`` (e.g. ``<element_text_is path="BlastOutput_program" text="blastp" />``).
``element_text_matches`` | Asserts the text of the XML element with the specified XPath-like ``path`` matches the regular expression defined by ``expression`` (e.g. ``<element_text_matches path="BlastOutput_version" expression="BLASTP\s+2\.2.*" />``).
``attribute_is`` | Asserts the XML ``attribute`` for the element (or tag) with the specified XPath-like ``path`` is the specified ``text`` (e.g. ``<attribute_is path="outerElement/innerElement1" attribute="foo" text="bar" />`` ).
``attribute_matches`` | Asserts the XML ``attribute`` for the element (or tag) with the specified XPath-like ``path`` matches the regular expression specified by ``expression`` (e.g. ``<attribute_matches path="outerElement/innerElement2" attribute="foo2" expression="bar\d+" />``).
``element_text`` | This tag allows the developer to recurisively specify additional assertions as child elements about just the text contained in the element specified by the XPath-like ``path`` (e.g. ``<element_text path="BlastOutput_iterations/Iteration/Iteration_hits/Hit/Hit_def"><not_has_text text="EDK72998.1" /></element_text>``).
``has_h5_keys`` | Asserts HDF5 output has a set of attributes (``keys``), specified as a comma-separated list (e.g. ``<has_h5_keys keys="bins,chroms,indexes,pixels,chroms/lengths" />``).
``has_h5_attribute`` | Asserts HDF5 output contains the specified ``value`` for an attribute (``key``) (e.g. ``<has_attr key="nchroms" value="15" />``).
``has_archive_member`` | This tag allows the developer to recursively specify additional assertions as child elements about just the member contained in the archive specified by the regular expression ``path`` (e.g. ``<has_archive_member path=".*/my-file.txt"><not_has_text text="EDK72998.1" /></has_archive_member>``). Valid archive formats include ``.zip``, ``.tar``, and ``.tar.gz``.
``has_size`` | Asserts the output has specific size (in bytes), e.g. ``<has_size value="10000" delta="100" />``.





## ``tool`` > ``help``

This tag set includes all of the necessary details of how to use the tool. This tag set should be included as the next to the last tag set, before citations, in the tool config. Tool help is written in reStructuredText. Included here is only an overview of a subset of features. For more information see [here](https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html).

tag | details
--- | -------
``.. class:: warningmark`` | a yellow warning symbol
``.. class:: infomark`` | a blue information symbol
``.. image:: path-of-the-file.png :height: 500 :width: 600`` | insert a png file of height 500 and width 600 at this position |
``**bold**`` | bold
``*italic*`` | italic
``*`` | list
``-`` | list
``::`` | paragraph
``-----`` | a horizontal line

### Examples

Show a warning sign to remind users that this tool accept fasta format files only, followed by an example of the query sequence and a figure.

```xml
<help>

.. class:: warningmark

'''TIP''' This tool requires *fasta* format.

----

'''Example'''

Query sequence::
    >seq1
    ATCG...

.. image:: my_figure.png
    :height: 500
    :width: 600

</help>
```



### Best Practices

Find the Intergalactic Utilities Commision suggested best practices for this
element [here](https://planemo.readthedocs.io/en/latest/standards/docs/best_practices/tool_xml.html#help-tag).



## ``tool`` > ``citations``

Tool files may declare one
citations element. Each citations element can contain one or more citation tag
elements - each of which specifies tool citation information using either a DOI
or a BibTeX entry.

These citations will appear at the bottom of the tool form in a formatted way
but the user will have to option to select RAW BibTeX for copying and pasting as
well. Likewise, the history menu includes an option allowing users to aggregate
all such citations across an analysis in a list of citations.

BibTeX entries for citations annotated with DOIs will be fetched by Galaxy from
https://doi.org/ and cached.

```xml
<citations>
   <!-- Example of annotating a citation using a DOI. -->
   <citation type="doi">10.1093/bioinformatics/btq281</citation>

   <!-- Example of annotating a citation using a BibTex entry. -->
   <citation type="bibtex">@ARTICLE{Kim07aninterior-point,
   author = {Seung-jean Kim and Kwangmoo Koh and Michael Lustig and Stephen Boyd and Dimitry Gorinevsky},
   title = {An interior-point method for large-scale l1-regularized logistic regression},
   journal = {Journal of Machine Learning Research},
   year = {2007},
   volume = {8},
   pages = {1519-1555}
   }</citation>
 </citations>
```

For more implementation information see the
[pull request](https://bitbucket.org/galaxy/galaxy-central/pull-requests/440/initial-bibtex-doi-citation-support-in/diff)
adding this feature. For more examples of how to add this to tools checkout the
following commits adding this to the
[NCBI BLAST+ suite](https://github.com/peterjc/galaxy_blast/commit/9d2e3906915895765ecc3f48421b91fabf2ccd8b),
[phenotype association tools](https://bitbucket.org/galaxy/galaxy-central/commits/39c983151fe328ff5d415f6da81ce5b21a7e18a4),
[MAF suite](https://bitbucket.org/galaxy/galaxy-central/commits/60f63d6d4cb7b73286f3c747e8acaa475e4b6fa8),
and [MACS2 suite](https://github.com/jmchilton/galaxytools/commit/184971dea73e236f11e82b77adb5cab615b8391b).

This feature was added to the August 2014 release of Galaxy, tools annotated
with citations will work in older releases of Galaxy but no citation information
will be available to the end user.




## ``tool`` > ``citations`` > ``citation``

Each citations element can contain one or
more ``citation`` tag elements - each of which specifies tool citation
information using either a DOI or a BibTeX entry.


### Attributes

Attribute | Details | Required
--- | --- | ---
``type`` | Type of citation - currently ``doi`` and ``bibtex`` are the only supported options. | True