Asynchronous email notifications, task execution

index 62f739d..c7f7409 100644
@@ -14,6 +14,7 @@ In order to make use of this application you will need:
 * Python 3.4+
 * Django 1.8.x - tested with 1.8.17; newer versions may work, but
   the application has not been tested with 1.9 or newer.
+* RabbitMQ 3.6.x - tested with 3.6.10.
 * For production usage, a web server set up to host Django applications
   (not needed for local-only testing)
 * A database supported by Django (SQLite, MySQL, etc.). Django takes

@@ -41,7 +42,9 @@ Setup instructions:
 1. Edit settings.py to specify a database, EMAIL_HOST, SECRET_KEY and
    other settings specific to your installation. Ensure you set
    LAYER_FETCH_DIR to an absolute path to a location with sufficient
-   space for fetching layer repositories.
+   space for fetching layer repositories. Modify RABBIT_BROKER
+   and RABBIT_BACKEND to reflect the settings used by your RabbitMQ
+   server.
 
 2. Run the following commands within the layerindex-web directory to
    initialise the database:

@@ -64,6 +67,11 @@ Setup instructions:
    production you need to use a proper web server and have DEBUG set
    to False.
 
+   3.1. In order to process asynchronous tasks like sending email,
+        you will need to run a Celery worker:
+
+        celery -A layerindex.tasks worker --loglevel=info
+
 4. You'll need to add at least the openembedded-core layer to the
    database, or some equivalent that contains conf/bitbake.conf for
    the base system configuration. To add this, follow these steps:

index 186219f..29986ac 100644
@@ -27,7 +27,6 @@ Other
 * Show layer type in layer detail?
 * Usage links in list page?
 * Subdirs in list page?
-* Prevent SMTP failures from breaking submission process
 * Query backend service i.e. special URL to query information for external apps/scripts
 * Add comparison to duplicates page
 * Create simple script to check for unlisted layer subdirectories in all repos

new file mode 100644
index 0000000..de80804
@@ -0,0 +1,24 @@
+from celery import Celery
+from django.core.mail import EmailMessage
+from . import utils
+import os
+import time
+
+try:
+    import settings
+except ImportError:
+    # not in a full django env, so settings is inaccessible.
+    # setup django to access settings.
+    utils.setup_django()
+    import settings
+
+tasks = Celery('layerindex',
+    broker=settings.RABBIT_BROKER,
+    backend=settings.RABBIT_BACKEND)
+
[email protected]
+def send_email(subject, text_content, from_email=settings.DEFAULT_FROM_EMAIL, to_emails=[]):
+    # We seem to need to run this within the task
+    utils.setup_django()
+    msg = EmailMessage(subject, text_content, from_email, to_emails)
+    msg.send()

index 1661cb3..bcf6671 100644
@@ -19,7 +19,6 @@ from layerindex.forms import EditLayerForm, LayerMaintainerFormSet, EditNoteForm
 from django.db import transaction
 from django.contrib.auth.models import User, Permission
 from django.db.models import Q, Count, Sum
-from django.core.mail import EmailMessage
 from django.template.loader import get_template
 from django.template import Context
 from django.utils.decorators import method_decorator

@@ -28,6 +27,7 @@ from django.contrib import messages
 from reversion.models import Revision
 from . import utils
 from . import simplesearch
+from . import tasks
 import settings
 from django.dispatch import receiver
 import reversion

@@ -181,8 +181,7 @@ def edit_layer_view(request, template_name, branch='master', slug=None):
                         from_email = settings.SUBMIT_EMAIL_FROM
                         to_email = user.email
                         text_content = plaintext.render(d)
-                        msg = EmailMessage(subject, text_content, from_email, [to_email])
-                        msg.send()
+                        tasks.send_email.apply_async((subject, text_content, from_email, [to_email]))
                     return HttpResponseRedirect(reverse('submit_layer_thanks'))
             messages.success(request, 'Layer %s saved successfully.' % layeritem.name)
             if return_url:

index f80e5d4..7cd741b 100644
@@ -1,3 +1,4 @@
+celery==3.1.25
 Django==1.8.17
 django-cors-headers==1.1.0
 django-nvd3==0.9.7

index 92146f8..e26f4b2 100644
@@ -224,3 +224,7 @@ FORCE_REVIEW_HTTPS = False
 # Settings for layer submission feature
 SUBMIT_EMAIL_FROM = '[email protected]'
 SUBMIT_EMAIL_SUBJECT = 'OE Layerindex layer submission'
+
+# RabbitMQ settings
+RABBIT_BROKER = 'amqp://'
+RABBIT_BACKEND = 'rpc://'