Extract cephx keys from vault encrypted files

Cephx keys are not picked up by "local_action: shell cat [...]"
when using ansible-vault encrypted keyrings.
This commit changes the logic to use the file lookup plugin and
extracts the key using jinja2 regex filters. The raw keys are then
set as ansible facts.

Closes-Bug: 1849127

Change-Id: Iacb1e42307c4de6a7a379e8cf279e073995fd5d3

ansible/roles/nova-cell/tasks/external_ceph.yml

@@ -79,26 +79,26 @@
     - Restart nova-libvirt container
 
 - name: Extract nova key from file
-  local_action: shell cat "{{ nova_cephx_keyring_file.stat.path }}" | grep -E 'key\s*=' | awk '{ print $3 }'
+  set_fact:
+    nova_cephx_raw_key: "{{ lookup('file', nova_cephx_keyring_file.stat.path) | regex_search('key\\s*=.*$', multiline=True) | regex_replace('key\\s*=\\s*(.*)\\s*', '\\1') }}"
   changed_when: false
   run_once: True
-  register: nova_cephx_raw_key
   when:
     - nova_backend == "rbd"
     - external_ceph_cephx_enabled | bool
 
 - name: Extract cinder key from file
-  local_action: shell cat "{{ cinder_cephx_keyring_file.stat.path }}" | grep -E 'key\s*=' | awk '{ print $3 }'
+  set_fact:
+    cinder_cephx_raw_key: "{{ lookup('file', cinder_cephx_keyring_file.stat.path) | regex_search('key\\s*=.*$', multiline=True) | regex_replace('key\\s*=\\s*(.*)\\s*', '\\1') }}"
   changed_when: false
   run_once: True
-  register: cinder_cephx_raw_key
   when:
     - cinder_backend_ceph | bool
     - external_ceph_cephx_enabled | bool
 
 - name: Pushing secrets key for libvirt
   copy:
-    content: "{{ item.result.stdout }}"
+    content: "{{ item.result }}"
     dest: "{{ node_config_directory }}/nova-libvirt/secrets/{{ item.uuid }}.base64"
     mode: "0600"
   become: true