Merge pull request #4433 from edx/jibsheet/xqueue-connection-pooling

Make sure XQueue can enable connection pooling

CHANGELOG.md

+- Role: xqueue
+  - Added XQUEUE_MYSQL_CONN_MAX_AGE so that you can have xqueue use django's persistent DB connections
 - Role: edxapp
   - Added empty `EDXAPP_PASSWORD_COMPLEXITY` setting to ease overriding complexity.
 

playbooks/roles/xqueue/defaults/main.yml

@@ -53,6 +53,8 @@ XQUEUE_MYSQL_PASSWORD: 'password'
 XQUEUE_MYSQL_HOST: 'localhost'
 XQUEUE_MYSQL_PORT: '3306'
 XQUEUE_MYSQL_OPTIONS: {}
+XQUEUE_MYSQL_CONN_MAX_AGE: 0 # This is Django's default https://docs.djangoproject.com/en/1.11/ref/settings/#conn-max-age
+
 XQUEUE_NEWRELIC_APPNAME: "{{ COMMON_ENVIRONMENT }}-{{ COMMON_DEPLOYMENT }}-xqueue"
 XQUEUE_SETTINGS_MODULE: "xqueue.aws_settings"
 # Set the number of workers explicitely for xqueue
@@ -121,6 +123,7 @@ xqueue_auth_config:
       HOST: "{{ XQUEUE_MYSQL_HOST }}"
       PORT: "{{ XQUEUE_MYSQL_PORT }}"
       ATOMIC_REQUESTS: True
+      CONN_MAX_AGE: "{{ XQUEUE_MYSQL_CONN_MAX_AGE }}"
       OPTIONS: "{{ XQUEUE_MYSQL_OPTIONS }}"
   RABBITMQ_USER: "{{ XQUEUE_RABBITMQ_USER }}"
   RABBITMQ_PASS: "{{ XQUEUE_RABBITMQ_PASS }}"