Asynchronous email notifications, task execution

This patch adds asynchronous task execution using a Celery backend
and RabbitMQ task queue, so that the layer submission process to
proceed even in the event that sending the notification email fails,
and establishing an asynchronous execution mechanism that we can use
in the future e.g. for triggering parse operations from the web UI.
This pertains to bug 11197:

https://bugzilla.yoctoproject.org/show_bug.cgi?id=11197

It updates the README to reflect the installation and configuration
of a basic RabbitMQ setup, adds a 'tasks.py' file to contain task
definitions, updates the 'edit_layer_view' function to send
emails to administrators about new and updated layers asynchronously,
modifies the 'settings.py' to include a default configuration
for a RabbitMQ connection, and updates the Dockerfile to start a Celery
worker alongside the Gunicorn daemon.

Fixes [YOCTO #11197].

Signed-off-by: Diana Thayer <garbados@gmail.com>
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>

1 files changed, 0 insertions, 1 deletions

diff --git a/TODO b/TODO
index 186219f74e..29986ac360 100644
--- a/TODO
+++ b/TODO
@@ -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