Integrated Celery startup / management / config with PillarServer.

pillar/__init__.py

@@ -60,6 +60,7 @@ class ConfigurationMissingError(SystemExit):
 class PillarServer(Eve):
     def __init__(self, app_root, **kwargs):
         from .extension import PillarExtension
+        from celery import Celery
 
         kwargs.setdefault('validator', custom_field_validation.ValidateCustomFields)
         super(PillarServer, self).__init__(settings=empty_settings, **kwargs)
@@ -106,6 +107,9 @@ class PillarServer(Eve):
 
         self._config_caching()
 
+        # Celery itself is configured after all extensions have loaded.
+        self.celery: Celery = None
+
         self.before_first_request(self.setup_db_indices)
 
     def _load_flask_config(self):
@@ -317,6 +321,30 @@ class PillarServer(Eve):
                                                'static_%s' % name,
                                                ext.static_path)
 
+    def _config_celery(self):
+        from celery import Celery
+
+        self.log.info('Configuring Celery')
+
+        # Pillar-defined Celery task modules:
+        celery_task_modules = [
+            'pillar.celery.tasks',
+            'pillar.celery.algolia_tasks',
+        ]
+
+        # Allow Pillar extensions from defining their own Celery tasks.
+        for extension in self.pillar_extensions.values():
+            celery_task_modules.extend(extension.celery_task_modules)
+
+        self.celery = Celery(
+            'pillar.celery',
+            backend=self.config['CELERY_BACKEND'],
+            broker=self.config['CELERY_BROKER'],
+            include=celery_task_modules,
+            task_track_started=True,
+            result_expires=3600,
+        )
+
     def register_static_file_endpoint(self, url_prefix, endpoint_name, static_folder):
         from pillar.web.staticfile import PillarStaticFile
 
@@ -475,6 +503,8 @@ class PillarServer(Eve):
     def finish_startup(self):
         self.log.info('Using MongoDB database %r', self.config['MONGO_DBNAME'])
 
+        self._config_celery()
+
         api.setup_app(self)
         web.setup_app(self)
         authentication.setup_app(self)

pillar/celery/algolia_tasks.py

@@ -4,12 +4,10 @@ import bson
 
 from pillar import current_app
 
-from .celery_cfg import celery_cfg
-
 log = logging.getLogger(__name__)
 
 
-@celery_cfg.task(ignore_result=True)
+@current_app.celery.task(ignore_result=True)
 def push_updated_user_to_algolia(user_id: str):
     """Push an update to the Algolia index when a user item is updated"""
 

pillar/celery/celery_cfg.py

@@ -1,20 +0,0 @@
-from celery import Celery
-
-task_modules = [
-    'pillar.celery.tasks',
-    'pillar.celery.algolia_tasks',
-]
-
-celery_cfg = Celery('proj',
-                    backend='redis://redis/1',
-                    broker='amqp://guest:guest@rabbit//',
-                    include=task_modules,
-                    task_track_started=True)
-
-# Optional configuration, see the application user guide.
-celery_cfg.conf.update(
-    result_expires=3600,
-)
-
-if __name__ == '__main__':
-    celery_cfg.start()

pillar/celery/tasks.py

@@ -1,12 +1,12 @@
 import logging
 import typing
 
-from .celery_cfg import celery_cfg
+from pillar import current_app
 
 log = logging.getLogger(__name__)
 
 
-@celery_cfg.task(track_started=True)
+@current_app.celery.task(track_started=True)
 def long_task(numbers: typing.List[int]):
     _log = log.getChild('long_task')
     _log.info('Computing sum of %i items', len(numbers))
@@ -18,4 +18,3 @@ def long_task(numbers: typing.List[int]):
     _log.info('Computed sum of %i items', len(numbers))
 
     return thesum
-

pillar/cli/operations.py

@@ -178,6 +178,4 @@ def worker(args):
                            # PyMongo client and reconnect after forking.
     ] + list(args)
 
-    from pillar.celery.celery_cfg import celery_cfg
-
-    celery_cfg.worker_main([argv0] + argvother)
+    current_app.celery.worker_main([argv0] + argvother)

pillar/config.py

@@ -155,3 +155,6 @@ EXTERNAL_SUBSCRIPTIONS_TIMEOUT_SECS = 10
 
 # Certificate file for communication with other systems.
 TLS_CERT_FILE = requests.certs.where()
+
+CELERY_BACKEND = 'redis://redis/1'
+CELERY_BROKER = 'amqp://guest:guest@rabbit//'

pillar/extension.py

@@ -16,6 +16,7 @@ can then be registered to the application at app creation time:
 """
 
 import abc
+import typing
 
 import flask
 import pillarsdk
@@ -25,6 +26,9 @@ class PillarExtension(object, metaclass=abc.ABCMeta):
     # Set to True when your extension implements the project_settings() method.
     has_project_settings = False
 
+    # List of Celery task modules introduced by this extension.
+    celery_task_modules: typing.List[str] = []
+
     @property
     @abc.abstractmethod
     def name(self):