Add config for the certificate agent queue polling frequency.

CHANGELOG.md

+- Role: certs
+  - Added `QUEUE_POLL_FREQUENCY` to make configurable the certificate agent's queue polling frequency.
+
 - Role: edxapp
   - Added `ENTERPRISE_REPORTING_SECRET` to CMS auth settings to allow edx-enterprise migrations to run.
 
 - Role: edxapp
   - Added `EDXAPP_FERNET_KEYS` to allow for use of django-fernet-keys in LMS.
-  
+
 - Role: edxapp
   - Added `EDX_PLATFORM_REVISION` (set from `edx_platform_version`). This is for
   edx-platform debugging purposes, and replaces calling dealer.git at startup.

playbooks/roles/certs/defaults/main.yml

@@ -53,6 +53,9 @@ CERTS_TEMPLATE_DATA_DIR: 'template_data'
 # gpg --export-ownertrust
 CERTS_OWNER_TRUST: "A9F9EAD11A0A6E7E5A037BDC044089B6FEF8D954:6:\n"
 
+# This is how long in seconds the cert agent will sleep before polling the queue again.
+CERTS_QUEUE_POLL_FREQUENCY: 5
+
 ########## Internal role vars below
 
 certs_user: certs
@@ -72,6 +75,7 @@ certs_env_config:
   CERT_DATA: {}
   QUEUE_NAME: "certificates"
   QUEUE_URL: "{{ CERTS_QUEUE_URL }}"
+  QUEUE_POLL_FREQUENCY: "{{ CERTS_QUEUE_POLL_FREQUENCY }}"
   CERT_BUCKET: "{{ CERTS_BUCKET }}"
   # gnupg signing key
   CERT_KEY_ID: "{{ CERTS_KEY_ID }}"