update collection followers in a task

apps/bandwagon/models.py

@@ -63,7 +63,7 @@ class CollectionManager(amo.models.ManagerBase):
         """Collections that are publishable by a user."""
         owned_by = Q(author=user.id)
         publishable_by = Q(users=user.id)
-        return self.filter(owned_by|publishable_by)
+        return self.filter(owned_by | publishable_by)
 
 
 class Collection(amo.models.ModelBase):
@@ -168,7 +168,8 @@ class Collection(amo.models.ModelBase):
                         args=[self.author_username, self.slug])
 
     def get_img_dir(self):
-        return os.path.join(settings.COLLECTIONS_ICON_PATH, str(self.id / 1000))
+        return os.path.join(settings.COLLECTIONS_ICON_PATH,
+                            str(self.id / 1000))
 
     def upvote_url(self):
         return reverse('collections.vote',
@@ -183,8 +184,8 @@ class Collection(amo.models.ModelBase):
                        args=[self.author_username, self.slug])
 
     def watch_url(self):
-       return reverse('collections.watch',
-                      args=[self.author_username, self.slug])
+        return reverse('collections.watch',
+                        args=[self.author_username, self.slug])
 
     def delete_url(self):
         return reverse('collections.delete',
@@ -395,6 +396,17 @@ class CollectionWatcher(amo.models.ModelBase):
         urls = ['*/user/%d/' % self.user_id]
         return urls
 
+    @staticmethod
+    def post_save_or_delete(sender, instance, **kw):
+        from . import tasks
+        tasks.collection_watchers(instance.collection_id, using='default')
+
+
+models.signals.post_save.connect(CollectionWatcher.post_save_or_delete,
+                                 sender=CollectionWatcher)
+models.signals.post_delete.connect(CollectionWatcher.post_save_or_delete,
+                                   sender=CollectionWatcher)
+
 
 class CollectionUser(models.Model):
     collection = models.ForeignKey(Collection)
@@ -428,7 +440,7 @@ class CollectionVote(models.Model):
 models.signals.post_save.connect(CollectionVote.post_save_or_delete,
                                  sender=CollectionVote)
 models.signals.post_delete.connect(CollectionVote.post_save_or_delete,
-                                 sender=CollectionVote)
+                                   sender=CollectionVote)
 
 
 class SyncedCollection(Collection):

apps/bandwagon/tasks.py

@@ -12,7 +12,8 @@ from PIL import Image
 import amo
 from tags.models import Tag
 from . import cron  # Pull in tasks run through cron.
-from .models import Collection, CollectionAddon, CollectionVote
+from .models import (Collection, CollectionAddon, CollectionVote,
+                     CollectionWatcher)
 
 log = logging.getLogger('z.task')
 
@@ -49,6 +50,7 @@ def resize_icon(src, dst):
     except Exception, e:
         log.error("Error saving collection icon: %s" % e)
 
+
 @task
 def delete_icon(dst):
     log.info('[1@None] Deleting icon: %s.' % dst)
@@ -84,6 +86,17 @@ def collection_meta(*ids, **kw):
                                                   all_personas=all_personas)
 
 
+@task
+def collection_watchers(*ids, **kw):
+    log.info('[%s@%s] Updating collection watchers.' %
+             (len(ids), collection_watchers.rate_limit))
+    using = kw.get('using')
+    for pk in ids:
+        watchers = (CollectionWatcher.objects.filter(collection=pk)
+                    .using(using).count())
+        Collection.objects.get(pk=pk).update(subscribers=watchers)
+
+
 @task(rate_limit='10/m')
 def cron_collection_meta(*addons):
     collection_meta(*addons)

apps/bandwagon/tests/test_models.py

@@ -6,8 +6,9 @@ import test_utils
 
 import amo
 from addons.models import Addon, AddonRecommendation
-from bandwagon.models import (Collection, CollectionUser, SyncedCollection,
-                              RecommendedCollection)
+from bandwagon.models import (Collection, CollectionUser, CollectionWatcher,
+                              SyncedCollection, RecommendedCollection)
+from bandwagon import tasks
 from users.models import UserProfile
 
 
@@ -17,12 +18,8 @@ def get_addons(c):
 
 
 class TestCollections(test_utils.TestCase):
-    fixtures = ('base/apps',
-                'base/users',
-                'base/addon_3615',
-                'base/collections',
-                'bandwagon/test_models'
-               )
+    fixtures = ['base/apps', 'base/users', 'base/addon_3615',
+                'base/collections', 'bandwagon/test_models']
 
     def setUp(self):
         self.user = UserProfile.objects.create(username='uhhh', email='uh@hh')
@@ -129,6 +126,14 @@ class TestCollections(test_utils.TestCase):
         c = Collection.objects.create(author=self.user, slug='boom')
         eq_(c.slug, 'boom-2')
 
+    def test_watchers(self):
+        def check(num):
+            eq_(Collection.objects.get(id=512).subscribers, num)
+        tasks.collection_watchers(512)
+        check(0)
+        CollectionWatcher.objects.create(collection_id=512, user=self.user)
+        check(1)
+
 
 class TestRecommendations(test_utils.TestCase):
     fixtures = ['base/addon-recs']

migrations/80-collection-triggers.sql

@@ -0,0 +1,2 @@
+DROP TRIGGER IF EXISTS collections_update_subscriber_count_delete;
+DROP TRIGGER IF EXISTS collections_update_subscriber_count_insert;