Merge pull request #2815 from edx/derf/make_databases_overridable

make databases overridable

playbooks/roles/edxapp/defaults/main.yml

@@ -633,6 +633,26 @@ EDXAPP_LMS_SPLIT_DOC_STORE_CONFIG:
 EDXAPP_CMS_DOC_STORE_CONFIG:
   <<: *edxapp_generic_default_docstore
 
+edxapp_databases:
+# edxapp's edxapp-migrate scripts and the edxapp_migrate play
+# will ensure that any DB not named read_replica will be migrated
+# for both the lms and cms.
+  read_replica:
+    ENGINE: 'django.db.backends.mysql'
+    NAME: "{{ EDXAPP_MYSQL_REPLICA_DB_NAME }}"
+    USER: "{{ EDXAPP_MYSQL_REPLICA_USER }}"
+    PASSWORD: "{{ EDXAPP_MYSQL_REPLICA_PASSWORD }}"
+    HOST: "{{ EDXAPP_MYSQL_REPLICA_HOST }}"
+    PORT: "{{ EDXAPP_MYSQL_REPLICA_PORT }}"
+  default:
+    ENGINE: 'django.db.backends.mysql'
+    NAME: "{{ EDXAPP_MYSQL_DB_NAME }}"
+    USER: "{{ EDXAPP_MYSQL_USER }}"
+    PASSWORD: "{{ EDXAPP_MYSQL_PASSWORD }}"
+    HOST: "{{ EDXAPP_MYSQL_HOST }}"
+    PORT: "{{ EDXAPP_MYSQL_PORT }}"
+    ATOMIC_REQUESTS: True
+
 edxapp_generic_auth_config:  &edxapp_generic_auth
   EVENT_TRACKING_SEGMENTIO_EMIT_WHITELIST: "{{ EDXAPP_EVENT_TRACKING_SEGMENTIO_EMIT_WHITELIST }}"
   ECOMMERCE_API_SIGNING_KEY: "{{ EDXAPP_ECOMMERCE_API_SIGNING_KEY }}"
@@ -661,24 +681,7 @@ edxapp_generic_auth_config:  &edxapp_generic_auth
       ssl: "{{ EDXAPP_MONGO_USE_SSL }}"
     ADDITIONAL_OPTIONS: "{{ EDXAPP_CONTENTSTORE_ADDITIONAL_OPTS }}"
     DOC_STORE_CONFIG: *edxapp_generic_default_docstore
-  DATABASES:
-    # edxapp's edxapp-migrate scripts and the edxapp_migrate play
-    # will ensure that any DB not named read_replica will be migrated
-    # for both the lms and cms.
-    read_replica:
-      ENGINE: 'django.db.backends.mysql'
-      NAME: "{{ EDXAPP_MYSQL_REPLICA_DB_NAME }}"
-      USER: "{{ EDXAPP_MYSQL_REPLICA_USER }}"
-      PASSWORD: "{{ EDXAPP_MYSQL_REPLICA_PASSWORD }}"
-      HOST: "{{ EDXAPP_MYSQL_REPLICA_HOST }}"
-      PORT: "{{ EDXAPP_MYSQL_REPLICA_PORT }}"
-    default:
-      ENGINE: 'django.db.backends.mysql'
-      NAME: "{{ EDXAPP_MYSQL_DB_NAME }}"
-      USER: "{{ EDXAPP_MYSQL_USER }}"
-      PASSWORD: "{{ EDXAPP_MYSQL_PASSWORD }}"
-      HOST: "{{ EDXAPP_MYSQL_HOST }}"
-      PORT: "{{ EDXAPP_MYSQL_PORT }}"
+  DATABASES: "{{ edxapp_databases }}"
   ANALYTICS_API_KEY:  "{{ EDXAPP_ANALYTICS_API_KEY }}"
   EMAIL_HOST_USER: "{{ EDXAPP_EMAIL_HOST_USER }}"
   EMAIL_HOST_PASSWORD: "{{ EDXAPP_EMAIL_HOST_PASSWORD }}"