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Source code for galaxy.web_stack.transport

"""Web application stack operations

import logging
import threading
from typing import List

from galaxy.util import unicodify

    import uwsgi
except ImportError:
    uwsgi = None

log = logging.getLogger(__name__)

[docs]class ApplicationStackTransport: SHUTDOWN_MSG = '__SHUTDOWN__'
[docs] def __init__(self, app, stack, dispatcher=None): """ Pre-fork initialization. """ self.app = app self.stack = stack self.can_run = False self.running = False self.dispatcher = dispatcher self.dispatcher_thread = None
[docs] def init_late_prefork(self): pass
def _dispatch_messages(self): pass
[docs] def start_if_needed(self): # Don't unnecessarily start a thread that we don't need. if self.can_run and not self.running and not self.dispatcher_thread and self.dispatcher and self.dispatcher.handler_count: self.running = True self.dispatcher_thread = threading.Thread(name=f"{self.__class__.__name__}.dispatcher_thread", target=self._dispatch_messages) self.dispatcher_thread.start() log.info('%s dispatcher started', self.__class__.__name__)
[docs] def stop_if_unneeded(self): if self.can_run and self.running and self.dispatcher_thread and self.dispatcher and not self.dispatcher.handler_count: self.running = False self.dispatcher_thread.join() self.dispatcher_thread = None log.info('%s dispatcher stopped', self.__class__.__name__)
[docs] def start(self): """ Post-fork initialization. """ self.can_run = True self.start_if_needed()
[docs] def send_message(self, msg, dest): pass
[docs] def shutdown(self): self.running = False if self.dispatcher_thread: log.info('Joining application stack transport dispatcher thread') self.dispatcher_thread.join() self.dispatcher_thread = None
[docs]class UWSGIFarmMessageTransport(ApplicationStackTransport): """ Communication via uWSGI Mule Farm messages. Communication is unidirectional (workers -> mules). """ # Define any static lock names here, additional locks will be appended for each configured farm's message handler _locks: List[str] = []
[docs] def init_late_prefork(self): num = int(uwsgi.opt.get('locks', 0)) + 1 need = len(self.stack._lock_farms) if num < need: raise RuntimeError('Need %i uWSGI locks but only %i exist(s): Set `locks = %i` in uWSGI configuration' % (need, num, need - 1)) self._locks.extend([f"RECV_MSG_FARM_{x}" for x in sorted(self.stack._lock_farms)])
# this would be nice, but in my 2.0.15 uWSGI, the uwsgi module has no set_option function, and I don't know if it'd work even if the function existed as documented # if len(self.lock_map) > 1: # uwsgi.set_option('locks', len(self.lock_map)) # log.debug('Created %s uWSGI locks' % len(self.lock_map))
[docs] def __init__(self, app, stack, dispatcher=None): super().__init__(app, stack, dispatcher=dispatcher)
def __lock(self, name_or_id): try: uwsgi.lock(name_or_id) except TypeError: uwsgi.lock(self._locks.index(name_or_id)) def __unlock(self, name_or_id): try: uwsgi.unlock(name_or_id) except TypeError: uwsgi.unlock(self._locks.index(name_or_id)) def _farm_recv_msg_lock_num(self): return self._locks.index(f"RECV_MSG_FARM_{self.stack._farm_name}") def _dispatch_messages(self): # this could be moved to the base class if locking was abstracted and a get_message method was added log.info('Application stack message dispatcher thread starting up') # we are going to do this a lot, so cache the lock number lock = self._farm_recv_msg_lock_num() while self.running: msg = None self.__lock(lock) try: log.debug('Acquired message lock, waiting for new message') msg = unicodify(uwsgi.farm_get_msg()) log.debug('Received message: %s', msg) if msg == self.SHUTDOWN_MSG: self.running = False else: self.dispatcher.dispatch(msg) except Exception: log.exception('Exception in mule message handling') finally: self.__unlock(lock) log.debug('Released lock') log.info('Application stack message dispatcher thread exiting') # TODO: start_if_needed would be called on a web worker by the stack's register_message_handler function if a # function were registered in a web handler, that should probably be prevented.
[docs] def start(self): """ Post-fork initialization. This is mainly done here for the future possibility that we'll be able to run mules post-fork without exec()ing. In a programmed mule it could be done at __init__ time. """ if self.stack._is_mule: if not uwsgi.in_farm(): raise RuntimeError('Mule %s is not in a farm! Set `farm = <pool_name>:%s` in uWSGI configuration' % (uwsgi.mule_id(), ','.join(map(str, range(1, len([x for x in self.stack._configured_mules if x.endswith('galaxy/main.py')]) + 1))))) elif len(self.stack._farms) > 1: raise RuntimeError(f'Mule {uwsgi.mule_id()} is in multiple farms! This configuration is not supported due to locking issues') # only mules receive messages so don't bother starting the dispatcher if we're not a mule (although # currently it doesn't have any registered handlers and so wouldn't start anyway) super().start()
[docs] def shutdown(self): if self.stack._is_mule: super().shutdown()
[docs] def send_message(self, msg, dest): log.debug('Sending message to farm %s: %s', dest, msg) uwsgi.farm_msg(dest, msg)