This document is for an old release of Galaxy. You can alternatively view this page in the latest release if it exists or view the top of the latest release's documentation.

Source code for galaxy.util.handlers

"""Utilities for dealing with the Galaxy 'handler' process pattern.

A 'handler' is a named Python process running the Galaxy application responsible
for some activity such as queuing up jobs or scheduling workflows.
from __future__ import absolute_import

import logging
import os
import random

log = logging.getLogger(__name__)

[docs]class ConfiguresHandlers: def _init_handlers(self, config_element): # Parse handlers if config_element is not None: for handler in self._findall_with_required(config_element, 'handler'): handler_id = handler.get('id') if handler_id in self.handlers: log.error("Handler '%s' overlaps handler with the same name, ignoring" % handler_id) else: log.debug("Read definition for handler '%s'" % handler_id) self.handlers[handler_id] = (handler_id,) self._parse_handler(handler_id, handler) if handler.get('tags', None) is not None: for tag in [x.strip() for x in handler.get('tags').split(',')]: if tag in self.handlers: self.handlers[tag].append(handler_id) else: self.handlers[tag] = [handler_id] def _parse_handler(self, handler_id, handler_def): pass def _get_default(self, config, parent, names): """ Returns the default attribute set in a parent tag like <handlers> or <destinations>, or return the ID of the child, if there is no explicit default and only one child. :param parent: Object representing a tag that may or may not have a 'default' attribute. :type parent: ``xml.etree.ElementTree.Element`` :param names: The list of destination or handler IDs or tags that were loaded. :type names: list of str :returns: str -- id or tag representing the default. """ rval = parent.get('default') if 'default_from_environ' in parent.attrib: environ_var = parent.attrib['default_from_environ'] rval = os.environ.get(environ_var, rval) elif 'default_from_config' in parent.attrib: config_val = parent.attrib['default_from_config'] rval = config.config_dict.get(config_val, rval) if rval is not None: # If the parent element has a 'default' attribute, use the id or tag in that attribute if rval not in names: raise Exception("<%s> default attribute '%s' does not match a defined id or tag in a child element" % (parent.tag, rval)) log.debug("<%s> default set to child with id or tag '%s'" % (parent.tag, rval)) elif len(names) == 1: log.info("Setting <%s> default to child with id '%s'" % (parent.tag, names[0])) rval = names[0] else: raise Exception("No <%s> default specified, please specify a valid id or tag with the 'default' attribute" % parent.tag) return rval def _findall_with_required(self, parent, match, attribs=None): """Like ``xml.etree.ElementTree.Element.findall()``, except only returns children that have the specified attribs. :param parent: Parent element in which to find. :type parent: ``xml.etree.ElementTree.Element`` :param match: Name of child elements to find. :type match: str :param attribs: List of required attributes in children elements. :type attribs: list of str :returns: list of ``xml.etree.ElementTree.Element`` """ rval = [] if attribs is None: attribs = ('id',) for elem in parent.findall(match): for attrib in attribs: if attrib not in elem.attrib: log.warning("required '%s' attribute is missing from <%s> element" % (attrib, match)) break else: rval.append(elem) return rval @property def is_handler(self): """Indicate whether the current server is a handler. :param server_name: The name to check :type server_name: str :return: bool """ if self._is_handler is not None: return self._is_handler for collection in self.handlers.values(): if self.app.config.server_name in collection: return True return False def _get_single_item(self, collection, index=None): """Given a collection of handlers or destinations, return one item from the collection at random. """ # Done like this to avoid random under the assumption it's faster to avoid it if len(collection) == 1: return collection[0] elif index is None: return random.choice(collection) else: return collection[index % len(collection)] # This is called by Tool.get_job_handler()
[docs] def get_handler(self, id_or_tag, index=None): """Given a handler ID or tag, return a handler matching it. :param id_or_tag: A handler ID or tag. :type id_or_tag: str :param index: Generate "consistent" "random" handlers with this index if specified. :type index: int :returns: str -- A valid job handler ID. """ if id_or_tag is None and self.default_handler_id is None: return None if id_or_tag is None: id_or_tag = self.default_handler_id return self._get_single_item(self.handlers[id_or_tag], index=index)