Make long-running tasks use async

This patch makes two long-running Horizon tasks use async:

  - compressing static files
  - compiling messages for translation

Combined, these steps take anywhere from 60-120 seconds to complete,
depending on the CI environment.

Change-Id: Ibee0a0f5ebfe575d1e336c2e98322bc0a85a7af7

tasks/horizon_post_install.yml

@@ -159,6 +159,9 @@
   with_items:
     - horizon
     - openstack_dashboard
+  register: async_compile_messages
+  async: 600
+  poll: 0
 
 - name: Collect and compress static files
   command: "{{ item }}"
@@ -169,3 +172,6 @@
     - "{{ horizon_bin }}/horizon-manage.py collectstatic --noinput"
     - "{{ horizon_bin }}/horizon-manage.py compress --force"
   notify: Restart apache2
+  register: async_compress_static_files
+  async: 600
+  poll: 0

tasks/main.yml

@@ -68,6 +68,30 @@
   tags:
     - horizon-config
 
+- name: Ensure messages are compiled for translation
+  async_status:
+    jid: "{{ item.ansible_job_id }}"
+  register: async_compile_messages_check
+  until: async_compile_messages_check.finished
+  retries: 300
+  with_items:
+    - "{{ async_compile_messages.results }}"
+
+# NOTE(mhayden): The async_status check here must be done as the horizon user
+# since the original task ran as that user. This task will fail if it is run
+# as root because the async status file is within the horizon user's home
+# directory, not root's home directory.
+- name: Ensure static files are collected and compressed
+  async_status:
+    jid: "{{ item.ansible_job_id }}"
+  become: yes
+  become_user: "{{ horizon_system_user_name }}"
+  register: async_compress_static_files_check
+  until: async_compress_static_files_check.finished
+  retries: 300
+  with_items:
+    - "{{ async_compress_static_files.results }}"
+
 - include: horizon_apache.yml
   tags:
     - horizon-config