Add optional task to rebuild the forum elasticsearch index

set FORUM_REBUILD_INDEX to run the rebuild_index rake task.

(cherry picked from commit d07e6fca)

CHANGELOG.md

+- Role: forum
+  - Added `FORUM_REBUILD_INDEX` to rebuild the ElasticSearch index from the database, when enabled.  Default: `False`.
+
 - Role: edxapp
   - Let `confirm_email` in `EDXAPP_REGISTRATION_EXTRA_FIELDS` default to `"hidden"`.
   - Let `terms_of_service` in `EDXAPP_REGISTRATION_EXTRA_FIELDS` default to `"hidden"`.

playbooks/roles/forum/defaults/main.yml

@@ -45,6 +45,9 @@ FORUM_USE_TCP: false
 # wait this long before attempting to restart it
 FORUM_RESTART_DELAY: 60
 
+# Set to rebuild the forum ElasticSearch index from the database.
+FORUM_REBUILD_INDEX: false
+
 forum_environment:
   RBENV_ROOT: "{{ forum_rbenv_root }}"
   GEM_HOME: "{{ forum_gem_root }}"

playbooks/roles/forum/tasks/deploy.yml

@@ -71,6 +71,17 @@
     - migrate
     - migrate:db
 
+- name: rebuild elasticsearch indexes
+  command: "{{ forum_code_dir }}/bin/rake search:rebuild_index"
+  args:
+    chdir: "{{ forum_code_dir }}"
+  become_user: "{{ forum_user }}"
+  environment: "{{ forum_environment }}"
+  when: migrate_db is defined and migrate_db|lower == "yes" and FORUM_REBUILD_INDEX|bool
+  tags:
+    - migrate
+    - migrate:db
+
   # call supervisorctl update. this reloads
   # the supervisorctl config and restarts
   # the services if any of the configurations