Fix venv build fallback mechanism

Fixes the ability to deploy a venv in cases where:
1) developer_mode is not enabled
2) A cached venv is not downloaded from the repo server

Also introduced is a var that can be used to disable the cached venv
download attempt entirely and force the fallback behavior. Previously
that would have been available by simply setting the venv download
to some broken URL like "http://localhost/none", but
keystone_venv_download will allow for much easier disabling of the
cached venv download behavior.

Change-Id: Ifb07eb2a73cc3478a36177d53a9a2b0579da4e12

defaults/main.yml

@@ -37,6 +37,9 @@ keystone_developer_constraints:
 keystone_venv_tag: untagged
 keystone_bin: "/openstack/venvs/keystone-{{ keystone_venv_tag }}/bin"
 
+# venv_download, even when true, will use the fallback method of building the
+# venv from scratch if the venv download fails.
+keystone_venv_download: "{{ not keystone_developer_mode | bool }}"
 keystone_venv_download_url: http://127.0.0.1/venvs/untagged/ubuntu/keystone.tgz
 
 keystone_fatal_deprecations: False

tasks/keystone_install.yml

@@ -191,7 +191,7 @@
     dest: "/var/cache/{{ keystone_venv_download_url | basename }}"
     checksum: "sha1:{{ lookup('url', keystone_venv_download_url | replace('tgz', 'checksum')) }}"
   register: keystone_get_venv
-  when: not keystone_developer_mode | bool
+  when: keystone_venv_download | bool
 
 - name: Remove existing venv
   file:
@@ -213,7 +213,7 @@
     copy: "no"
   when:
     - not keystone_developer_mode | bool
-    - keystone_get_venv | changed or keystone_venv_dir | changed
+    - keystone_get_venv | changed
   notify:
     - Restart Keystone APIs on first node
     - Restart Keystone APIs on other nodes
@@ -234,7 +234,7 @@
   until: install_packages|success
   retries: 5
   delay: 2
-  when: keystone_developer_mode | bool
+  when: not keystone_get_venv | success or keystone_developer_mode | bool
   notify:
     - Restart Keystone APIs on first node
     - Restart Keystone APIs on other nodes