Initial commit to support Celery 4.3.0

Merges 55e9b2263c from versions/next
with code from GitLab issue #594 and GitLab merge request !55.

Thanks to Jakob Haufe (@sur5r) and Jesaja Everling (@jeverling)
for much of the research and code updates.

Signed-off-by: Roberto Rosario <roberto.rosario@mayan-edms.com>

docs/chapters/deploying.rst

@@ -220,11 +220,11 @@ of a restart or power failure. The Gunicorn workers are increased to 3.
 ---------------------------------------------------------------------
    Replace (paying attention to the comma at the end)::
 
-       MAYAN_BROKER_URL="redis://127.0.0.1:6379/0",
+       MAYAN_CELERY_BROKER_URL="redis://127.0.0.1:6379/0",
 
    with::
 
-       MAYAN_BROKER_URL="amqp://mayan:mayanrabbitmqpassword@localhost:5672/mayan",
+       MAYAN_CELERY_BROKER_URL="amqp://mayan:mayanrabbitmqpassword@localhost:5672/mayan",
 
    increase the number of Gunicorn workers to 3 in the line (``-w 2`` section)::
 

docs/chapters/docker.rst

@@ -190,7 +190,7 @@ the default port. Not used with SQLite. For more information read the
 pertinent Django documentation page:
 :django-docs:`Settings, PORT <ref/settings/#port>`
 
-``MAYAN_BROKER_URL``
+``MAYAN_CELERY_BROKER_URL``
 
 This optional environment variable determines the broker that Celery will use
 to relay task messages between the frontend code and the background workers.
@@ -200,7 +200,7 @@ For more information read the pertinent Celery Kombu documentation page: `Broker
 
 This Docker image supports using Redis and RabbitMQ as brokers.
 
-Caveat: If the `MAYAN_BROKER_URL` and `MAYAN_CELERY_RESULT_BACKEND` environment
+Caveat: If the `MAYAN_CELERY_BROKER_URL` and `MAYAN_CELERY_RESULT_BACKEND` environment
 variables are specified, the built-in Redis server inside the container will
 be disabled.
 
@@ -215,7 +215,7 @@ code. For more information read the pertinent Celery Kombu documentation page:
 
 This Docker image supports using Redis and RabbitMQ as result backends.
 
-Caveat: If the `MAYAN_BROKER_URL` and `MAYAN_CELERY_RESULT_BACKEND` environment
+Caveat: If the `MAYAN_CELERY_BROKER_URL` and `MAYAN_CELERY_RESULT_BACKEND` environment
 variables are specified, the built-in Redis server inside the container will
 be disabled.
 

docs/chapters/scaling_up.rst

@@ -94,11 +94,11 @@ For the Docker image, launch a separate RabbitMQ container
 
     docker run -d --name mayan-edms-rabbitmq -e RABBITMQ_DEFAULT_USER=mayan -e RABBITMQ_DEFAULT_PASS=mayanrabbitmqpassword -e RABBITMQ_DEFAULT_VHOST=mayan rabbitmq:3
 
-Pass the MAYAN_BROKER_URL environment variable (https://kombu.readthedocs.io/en/latest/userguide/connections.html#connection-urls)
+Pass the MAYAN_CELERY_BROKER_URL environment variable (https://kombu.readthedocs.io/en/latest/userguide/connections.html#connection-urls)
 to the Mayan EDMS container so that it uses the RabbitMQ container the
 message broker::
 
-    -e MAYAN_BROKER_URL="amqp://mayan:mayanrabbitmqpassword@localhost:5672/mayan",
+    -e MAYAN_CELERY_BROKER_URL="amqp://mayan:mayanrabbitmqpassword@localhost:5672/mayan",
 
 When tasks finish, they leave behind a return status or the result of a
 calculation, these are stored for a while so that whoever requested the

docs/releases/3.3.rst

@@ -52,7 +52,9 @@ Changes
 - Backport file cache manager app.
 - Convert document image cache to use file cache manager app.
   Add setting DOCUMENTS_CACHE_MAXIMUM_SIZE defaults to 500 MB.
-  
+- Update Celery to version 4.3.0. Settings changed:
+  MAYAN_BROKER_URL to MAYAN_CELERY_BROKER_URL,
+  MAYAN_CELERY_ALWAYS_EAGER to MAYAN_CELERY_TASK_ALWAYS_EAGER.
 
 Removals
 --------