Add ability to change apt/yum package state

The current method of installing the distribution packages required is
set in the tasks and cannot be changed by a deployer.

Currently the apt task always installs the latest package. This results
in unexpected binary changes when a deployer may simply be trying to
execute a configuration change.

This patch adds the ability for a deployer to change the desired state
so that the results are predictable.

Change-Id: I7ddc32b286071b29c197b18370cf49af235527fa

defaults/main.yml

@@ -13,6 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# Set the package install state for distribution packages
+# Options are 'present' and 'latest'
+pip_install_package_state: "latest"
+
 ## Path to pip download/installation script.
 pip_upstream_url: https://bootstrap.pypa.io/get-pip.py
 pip_fallback_url: https://raw.githubusercontent.com/pypa/get-pip/master/get-pip.py

releasenotes/notes/package-state-505f9772bb0d668e.yaml

@@ -0,0 +1,14 @@
+---
+features:
+  - The pip_install role now supports the ability to configure whether
+    apt/yum tasks install the latest available package, or just ensure
+    that the package is present. The default action is to ensure that
+    the latest package is present. The action taken may be changed to
+    only ensure that the package is present by setting
+    ``pip_install_package_state`` to ``present``.
+upgrade:
+  - The pip_install role always checks whether the latest package is
+    installed when executed. If a deployer wishes to change the check to
+    only validate the presence of the package, the option
+    ``pip_install_package_state`` should be set to ``present``.
+

tasks/install_binary.yml

@@ -16,7 +16,7 @@
 - name: Install python-pip (yum)
   yum:
     pkg: "{{ python_pip_package }}"
-    state: "latest"
+    state: "{{ pip_install_package_state }}"
   register: install_packages
   until: install_packages|success
   retries: 5
@@ -27,7 +27,7 @@
 - name: Install python-pip (apt)
   apt:
     pkg: "{{ python_pip_package }}"
-    state: "latest"
+    state: "{{ pip_install_package_state }}"
   register: install_packages
   until: install_packages|success
   retries: 5