Added support for django-celery-transactions. Closes django-haystack#7.

Author: jezdez

README.rst

@@ -34,7 +34,13 @@ By default a few dependencies will automatically be installed:
 
 - django-appconf_ -- An app to gracefully handle application settings.
 
+- `django-celery-transactions`_ -- An app that "holds on to Celery tasks
+  until the current database transaction is committed, avoiding potential
+  race conditions as described in `Celery's user guide`_."
+
 .. _django-appconf: http://pypi.python.org/pypi/django-appconf
+.. _`django-celery-transactions`: https://github.com/chrisdoble/django-celery-transactions 
+.. _`Celery's user guide`: http://celery.readthedocs.org/en/latest/userguide/tasks.html#database-transactions
 
 Setup
 -----

celery_haystack/conf.py

@@ -8,6 +8,7 @@ class CeleryHaystack(AppConf):
     RETRY_DELAY = 5 * 60
     MAX_RETRIES = 1
     DEFAULT_TASK = 'celery_haystack.tasks.CeleryHaystackSignalHandler'
+    TRANSACTION_SAFE = True
 
     COMMAND_BATCH_SIZE = None
     COMMAND_AGE = None

celery_haystack/tasks.py

@@ -2,7 +2,6 @@
 from django.core.management import call_command
 from django.db.models.loading import get_model
 
-from celery.task import Task
 from celery_haystack.conf import settings
 
 try:
@@ -18,6 +17,11 @@
     except ImportError, e:
         raise ImproperlyConfigured("Haystack couldn't be imported: %s" % e)
 
+if settings.CELERY_HAYSTACK_TRANSACTION_SAFE:
+    from djcelery_transactions import PostTransactionTask as Task
+else:
+    from celery.task import Task  # noqa
+
 
 class CeleryHaystackSignalHandler(Task):
     using = settings.CELERY_HAYSTACK_DEFAULT_ALIAS
@@ -112,8 +116,8 @@ def run(self, action, identifier, **kwargs):
         current_index = self.get_index(model_class, **kwargs)
 
         if action == 'delete':
-            # If the object is gone, we'll use just the identifier against the
-            # index.
+            # If the object is gone, we'll use just the identifier
+            # against the index.
             try:
                 handler_options = self.get_handler_options(**kwargs)
                 current_index.remove_object(identifier, **handler_options)

docs/changelog.rst

@@ -1,6 +1,23 @@
 Changelog
 =========
 
+v0.6 (2012-06-27)
+-----------------
+
+* *backwards incompatible change* Added support for
+  `django-celery-transactions`_ to make sure the tasks are respecting
+  Django's transaction management. It holds on to Celery tasks
+  until the current database transaction is committed, avoiding potential
+  race conditions as described in `Celery's user guide`_.
+
+  This is **enabled by default** but can be disabled in case you want
+  to manually manage the tranasctions:
+
+      CELERY_HAYSTACK_TRANSACTION_SAFE = False
+
+.. _`django-celery-transactions`: https://github.com/chrisdoble/django-celery-transactions 
+.. _`Celery's user guide`: http://celery.readthedocs.org/en/latest/userguide/tasks.html#database-transactions
+
 v0.5 (2012-05-23)
 -----------------
 

setup.py

@@ -39,7 +39,8 @@ def find_version(*file_paths):
         'Topic :: Utilities',
     ],
     install_requires=[
-        'django-appconf >= 0.4.1',
+        'django-appconf>=0.4.1',
+        'django-celery-transactions>=0.1.2'
     ],
     zip_safe=False,
 )