Files
edx-platform/openedx/core/lib/celery/routers.py
2016-11-29 09:43:56 -05:00

62 lines
2.0 KiB
Python

"""
Custom routers used by both lms and cms when routing tasks to worker queues.
For more, see http://celery.readthedocs.io/en/latest/userguide/routing.html#routers
"""
from abc import ABCMeta, abstractproperty
from django.conf import settings
import logging
log = logging.getLogger(__name__)
class AlternateEnvironmentRouter(object):
"""
A custom Router class for use in routing celery tasks to non-default queues.
"""
# this is an abstract base class, implementations must provide alternate_env_tasks
__metaclass__ = ABCMeta
@abstractproperty
def alternate_env_tasks(self):
"""
Defines the task -> alternate worker environment queue to be used when routing.
Subclasses must override this property with their own specific mappings.
"""
return {}
def route_for_task(self, task, args=None, kwargs=None): # pylint: disable=unused-argument
"""
Celery-defined method allowing for custom routing logic.
If None is returned from this method, default routing logic is used.
"""
alternate_env = self.alternate_env_tasks.get(task, None)
if 'update_course_in_cache' in task:
log.info("TNL-5408: task={task}, args={args}, alternate_env={alt_env}, queues={queues}".format(
task=task,
args=args,
alt_env=alternate_env,
queues=getattr(settings, 'CELERY_QUEUES', []).keys()
))
if alternate_env:
return self.ensure_queue_env(alternate_env)
return None
def ensure_queue_env(self, desired_env):
"""
Helper method to get the desired type of queue.
If no such queue is defined, default routing logic is used.
"""
queues = getattr(settings, 'CELERY_QUEUES', None)
return next(
(
queue
for queue in queues
if '.{}.'.format(desired_env) in queue
),
None
)