Clean up developer mode logic

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

Additional cleanup to the developer_mode venv deployment
logic is implemented by adding a *_venv_download var
which is used to decouple developer_mode from the
cached venv extraction process so that a deployer
can force venv builds in-place (disable cached
venv usage) without enabling developer mode
constraints.

Change-Id: Id4e911dd28bf3e22fe5927b06464ee15c57f010e

defaults/main.yml

@@ -68,6 +68,9 @@ trove_profiler_enabled: false
 trove_venv_tag: untagged
 trove_bin: "/openstack/venvs/trove-{{ trove_venv_tag }}/bin"
 
+# venv_download, even when true, will use the fallback method of building the
+# venv from scratch if the venv download fails.
+trove_venv_download: "{{ not trove_developer_mode | bool }}"
 trove_venv_download_url: http://127.0.0.1/venvs/untagged/ubuntu/trove.tgz
 
 trove_git_repo: "https://git.openstack.org/openstack/trove"

tasks/trove_install.yml

@@ -61,7 +61,7 @@
     dest: "/var/cache/{{ trove_venv_download_url | basename }}"
     checksum: "sha1:{{ lookup('url', trove_venv_download_url | replace('tgz', 'checksum')) }}"
   register: trove_get_venv
-  when: not trove_developer_mode | bool
+  when: trove_venv_download | bool
 
 - name: Remove existing venv
   file:
@@ -75,15 +75,14 @@
     state: directory
     mode: "0755"
   register: trove_venv_dir
+  when: trove_get_venv | changed
 
 - name: Unarchive pre-built venv
   unarchive:
     src: "/var/cache/{{ trove_venv_download_url | basename }}"
     dest: "{{ trove_bin | dirname }}"
     copy: "no"
-  when:
-    - not trove_developer_mode | bool
-    - trove_get_venv | changed or trove_venv_dir | changed
+  when: trove_get_venv | changed
   notify:
     - Restart trove API services
     - Restart trove conductor service
@@ -104,7 +103,7 @@
   until: install_packages|success
   retries: 5
   delay: 2
-  when: trove_developer_mode | bool
+  when: trove_get_venv | failed or trove_get_venv | skipped
   notify:
     - Restart trove API services
     - Restart trove conductor service
@@ -114,6 +113,4 @@
 - name: Update virtualenv path
   command: >
     virtualenv-tools --update-path=auto --reinitialize {{ trove_bin | dirname }}
-  when:
-    - not trove_developer_mode | bool
-    - trove_get_venv | changed or trove_venv_dir | changed
+  when: trove_get_venv | changed