Optimise the distro package installation

In order to optimise the distro package installation
process the list of packages to install is prepared
for the host, then installed by passing the package
task the full list instead of using a loop.

The package lists in defaults are removed as it is
undesirable to make it easy to override these lists.
This is not provided for in any other roles.

Combined backport of:
- https://review.openstack.org/457391
- https://review.openstack.org/458519
- https://review.openstack.org/472305

Change-Id: I71307d2a808fdc0f76e376a84651dad86b3f8b69

defaults/main.yml

@@ -39,6 +39,4 @@ memcached_connections: 1024
 memcached_threads: 4
 memcached_file_limits: "{{ memcached_connections | int + 1024 }}"
 
-memcached_distro_packages: []
-memcached_test_distro_packages: []
 install_test_packages: False

meta/main.yml

@@ -18,7 +18,7 @@ galaxy_info:
   description: Installation and setup of memcached
   company: Rackspace
   license: Apache2
-  min_ansible_version: 1.6.6
+  min_ansible_version: 2.2
   platforms:
     - name: Ubuntu
       versions:

tasks/install-apt.yml

@@ -1,37 +0,0 @@
----
-# Copyright 2016, Rackspace US, Inc.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-- name: Install apt packages
-  apt:
-    pkg: "{{ item }}"
-    state: "{{ memcached_package_state }}"
-    update_cache: yes
-    cache_valid_time: "{{ cache_timeout }}"
-  register: install_packages
-  until: install_packages|success
-  retries: 5
-  delay: 2
-  with_items: "{{ memcached_distro_packages }}"
-
-- name: Install apt packages for testing
-  apt:
-    pkg: "{{ item }}"
-    state: "{{ memcached_package_state }}"
-  register: install_test_packages
-  until: install_test_packages|success
-  retries: 5
-  delay: 2
-  with_items: "{{ memcached_test_distro_packages }}"
-  when: install_test_packages|bool

tasks/install-yum.yml

@@ -1,44 +0,0 @@
----
-# Copyright 2016, Rackspace US, Inc.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-- name: yum clean all
-  command: "/usr/bin/yum clean all"
-  register: yum_clean
-  until: yum_clean | success
-  retries: 5
-  delay: 2
-  tags:
-    - skip_ansible_lint
-
-- name: Install yum packages
-  yum:
-    pkg: "{{ item }}"
-    state: "{{ memcached_package_state }}"
-  register: install_yum_packages
-  until: install_yum_packages | success
-  retries: 5
-  delay: 2
-  with_items: "{{ memcached_distro_packages }}"
-
-- name: Install yum packages for testing
-  yum:
-    pkg: "{{ item }}"
-    state: "{{ memcached_package_state }}"
-  register: install_yum_test_packages
-  until: install_yum_test_packages | success
-  retries: 5
-  delay: 2
-  with_items: "{{ memcached_test_distro_packages }}"
-  when: install_test_packages|bool

tasks/memcached_install.yml

@@ -13,12 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-- include: install-apt.yml
-  static: no
-  when:
-    - ansible_pkg_mgr == 'apt'
-
-- include: install-yum.yml
-  static: no
-  when:
-    - ansible_pkg_mgr == 'yum'
+- name: Install distro packages
+  package:
+    name: "{{ memcached_package_list }}"
+    state: "{{ memcached_package_state }}"
+    update_cache: "{{ (ansible_pkg_mgr == 'apt') | ternary('yes', omit) }}"
+    cache_valid_time: "{{ (ansible_pkg_mgr == 'apt') | ternary(cache_timeout, omit) }}"
+  register: install_packages
+  until: install_packages | success
+  retries: 5
+  delay: 2

vars/main.yml

@@ -0,0 +1,26 @@
+---
+# Copyright 2017, Rackspace US, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+#
+# Compile a list of the distro packages to install based on
+# whether the host is in the host group and the service is
+# enabled.
+#
+memcached_package_list: |-
+  {% set packages = memcached_distro_packages %}
+  {% if install_test_packages | bool %}
+  {%   set _ = packages.extend(memcached_test_distro_packages) %}
+  {% endif %}
+  {{ packages }}