# HG changeset patch
# User domruf <dominikruf@gmail.com>
# Date 2017-06-11 16:13:09
# Node ID b9853a3cc2548fb0318fa127b8da112c60d39349
# Parent  970ee88be388fccd7b9230f3db9ba7b57067ad7d

celery: simplify internal configuration and app creation

We used celery.app.app_or_default() which creates a "global fallback app
instance" which relies on the CELERY_LOADER environment variable to load the
configuration. That worked but was messy.

Instead, do something more like described in
http://docs.celeryproject.org/en/3.1/userguide/application.html where the app
is a celery.Celery() instance and configuration is loaded explicitly by its
config_from_object method. Using config_from_object we don't need explicit
invocation of import_default_modules and can take pass PylonsSettingsProxy
directly, leaving PylonsLoader unused and removed.

Modified by Mads Kiilerich.

diff --git a/kallithea/lib/celerypylons/__init__.py b/kallithea/lib/celerypylons/__init__.py
--- a/kallithea/lib/celerypylons/__init__.py
+++ b/kallithea/lib/celerypylons/__init__.py
@@ -3,10 +3,8 @@
 """
 Kallithea wrapper of Celery
 
-The Celery configuration is in the normal Pylons ini file. We thus have to set
-the `CELERY_LOADER` environment variable to point at a custom "loader" that can
-read it. That environment variable must be set *before* importing celery. To
-ensure that, we wrap celery in this module.
+The Celery configuration is in the ini file. To read the settings and translate
+to a Celery format we use PylonsSettingsProxy.
 
 We read the configuration from tg.config, thus it must be initialized before
 loading this module. To make sure that really is the case and give an early
@@ -19,20 +17,17 @@ demand in function scope after tg.config
 import os
 import warnings
 
-import celery.app
+import celery
+
+from kallithea.lib.celerypylons.loader import PylonsSettingsProxy
 
 # Verify Pylons configuration has been loaded
 from tg import config
 assert config['celery.imports'] == 'kallithea.lib.celerylib.tasks', 'Kallithea Celery configuration has not been loaded'
 
-# Prepare environment to point at Kallithea Pylons loader
-CELERYPYLONS_LOADER = 'kallithea.lib.celerypylons.loader.PylonsLoader'
-if os.environ.get('CELERY_LOADER', CELERYPYLONS_LOADER) != CELERYPYLONS_LOADER:
-    warnings.warn("'CELERY_LOADER' environment variable will be overridden by celery-pylons.")
-os.environ['CELERY_LOADER'] = CELERYPYLONS_LOADER
-
-# Create celery app, thus immediately triggering use of the custom Pylons loader
-app = celery.app.app_or_default()
+# Create celery app from the TurboGears configuration file
+app = celery.Celery()
+app.config_from_object(PylonsSettingsProxy())
 
 import celery.result as result
 from celery.task import task
diff --git a/kallithea/lib/celerypylons/loader.py b/kallithea/lib/celerypylons/loader.py
--- a/kallithea/lib/celerypylons/loader.py
+++ b/kallithea/lib/celerypylons/loader.py
@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 
-from celery.loaders.base import BaseLoader
 from tg import config
 
 # TODO: drop this mangling and just use a separate celery config section
@@ -59,19 +58,3 @@ class PylonsSettingsProxy(object):
         if value.lower() in ['true', 'false']:
             return value.lower() == 'true'
         return value
-
-class PylonsLoader(BaseLoader):
-    """Pylons celery loader
-
-    Maps the celery config onto pylons.config
-
-    """
-    def read_configuration(self):
-        self.configured = True
-        return PylonsSettingsProxy()
-
-    def on_worker_init(self):
-        """
-        Import task modules.
-        """
-        self.import_default_modules()