Use updated get_url module checksum functionality

Starting in Ansible 2.0, the get_url [1] module provides the
ability for a checksum to be provided to the get_url module
which will be verified against the local destination file
and the task skipped if it matches.

[1] http://docs.ansible.com/ansible/get_url_module.html

This patch implements the use of this functionality.

The ability to ignore a venv download failure is also removed
as this is not necessary or desirable. It is better for the
download to fail and the playbook execution to stop immediately
so that the failure point is exposed.

Change-Id: Ib457a9c68f4cf627b0496574cda628ed304692c1

meta/main.yml

@@ -18,7 +18,7 @@ galaxy_info:
   description: Installation and setup of cloudkitty
   company: Rackspace
   license: Apache2
-  min_ansible_version: 1.9
+  min_ansible_version: 2.0
   platforms:
     - name: Ubuntu
       versions:

tasks/cloudkitty_install.yml

@@ -54,51 +54,13 @@
     - cloudkitty-install
     - cloudkitty-pip-packages
 
-- name: Get local venv checksum
-  stat:
-    path: "/var/cache/{{ cloudkitty_venv_download_url | basename }}"
-    get_md5: False
-  when:
-    - not cloudkitty_developer_mode | bool
-  register: local_venv_stat
-  tags:
-    - cloudkitty-install
-    - cloudkitty-pip-packages
-
-- name: Get remote venv checksum
-  uri:
-    url: "{{ cloudkitty_venv_download_url | replace('tgz', 'checksum') }}"
-    return_content: True
-  when:
-    - not cloudkitty_developer_mode | bool
-  register: remote_venv_checksum
-  tags:
-    - cloudkitty-install
-    - cloudkitty-pip-packages
-
-# TODO: When project moves to ansible 2 we can pass this a sha256sum which will:
-#       a) allow us to remove force: yes
-#       b) allow the module to calculate the checksum of dest file which would
-#          result in file being downloaded only if provided and dest sha256sum
-#          checksums differ
 - name: Attempt venv download
   get_url:
     url: "{{ cloudkitty_venv_download_url }}"
     dest: "/var/cache/{{ cloudkitty_venv_download_url | basename }}"
-    force: yes
-  failed_when: false
-  register: get_venv
-  when:
-    - not cloudkitty_developer_mode | bool
-    - (local_venv_stat.stat.exists == False or
-        {{ local_venv_stat.stat.checksum is defined and local_venv_stat.stat.checksum != remote_venv_checksum.content | trim }})
-  tags:
-    - cloudkitty-install
-    - cloudkitty-pip-packages
-
-- name: Set cloudkitty get_venv fact
-  set_fact:
-    cloudkitty_get_venv: "{{ get_venv }}"
+    checksum: "sha1:{{ lookup('url', cloudkitty_venv_download_url | replace('tgz', 'checksum')) }}"
+  register: cloudkitty_get_venv
+  when: not cloudkitty_developer_mode | bool
   tags:
     - cloudkitty-install
     - cloudkitty-pip-packages
@@ -107,8 +69,7 @@
   file:
     path: "{{ cloudkitty_bin | dirname }}"
     state: absent
-  when:
-    - cloudkitty_get_venv | changed
+  when: cloudkitty_get_venv | changed
   tags:
     - cloudkitty-install
     - cloudkitty-pip-packages
@@ -150,8 +111,7 @@
   until: install_packages|success
   retries: 5
   delay: 2
-  when:
-    - cloudkitty_get_venv | failed or cloudkitty_developer_mode | bool
+  when: cloudkitty_developer_mode | bool
   notify:
     - Restart cloudkitty services
   tags:
@@ -163,7 +123,7 @@
     virtualenv-tools --update-path=auto {{ cloudkitty_bin | dirname }}
   when:
     - not cloudkitty_developer_mode | bool
-    - cloudkitty_get_venv | success
+    - cloudkitty_get_venv | changed or cloudkitty_venv_dir | changed
   tags:
     - cloudkitty-install
     - cloudkitty-pip-packages