Add ability to disable backend packages management

There are use cases where an user wants to not have backend packages
automatically installed. One use case would be the user having an alternative
set of packages already providing backend packages as built-in dependencies.
Installing system packages is redundant, useless and causing confusion.

This change adds the ability to disable backend packages management
while preserving previous behavior which consists of installing them
automatically.

Closes-bug: #1715204
Change-Id: Ief676d4c5aaa81f4547dd2e090dfcc8c62855148

manifests/cache.pp

@@ -113,6 +113,10 @@
 #   client connection. (integer value)
 #   Defaults to $::os_service_default
 #
+# [*manage_backend_package*]
+#   (Optional) Whether to install the backend package.
+#   Defaults to true.
+#
 define oslo::cache(
   $config_prefix                        = $::os_service_default,
   $expiration_time                      = $::os_service_default,
@@ -127,6 +131,7 @@ define oslo::cache(
   $memcache_pool_maxsize                = $::os_service_default,
   $memcache_pool_unused_timeout         = $::os_service_default,
   $memcache_pool_connection_get_timeout = $::os_service_default,
+  $manage_backend_package               = true,
 ){
 
   include ::oslo::params
@@ -149,17 +154,19 @@ define oslo::cache(
     $proxies_orig = $proxies
   }
 
-  if ($backend =~ /pylibmc/ ) {
+  if $manage_backend_package {
-    ensure_packages('python-pylibmc', {
+    if ($backend =~ /pylibmc/ ) {
-      ensure => present,
+      ensure_packages('python-pylibmc', {
-      name   => $::oslo::params::pylibmc_package_name,
+        ensure => present,
-      tag    => 'openstack',
+        name   => $::oslo::params::pylibmc_package_name,
-    })
+        tag    => 'openstack',
-  } elsif ($backend =~ /\.memcache/ ) {
+      })
-    ensure_resources('package', { 'python-memcache' => {
+    } elsif ($backend =~ /\.memcache/ ) {
-      name   => $::oslo::params::python_memcache_package_name,
+      ensure_resources('package', { 'python-memcache' => {
-      tag    => ['openstack'],
+        name   => $::oslo::params::python_memcache_package_name,
-    }})
+        tag    => ['openstack'],
+      }})
+    }
   }
 
   $cache_options = {

manifests/db.pp

@@ -15,6 +15,10 @@
 #   (Optional) The back end to use for the database.
 #   Defaults to $::os_service_default
 #
+# [*manage_backend_package*]
+#   (Optional) Whether to install the backend package.
+#   Defaults to true.
+#
 # [*backend_package_ensure*]
 #   (Optional) Desired ensure state of the backend database package,
 #   accepts latest or specific versions.
@@ -105,6 +109,7 @@
 define oslo::db(
   $sqlite_synchronous     = $::os_service_default,
   $backend                = $::os_service_default,
+  $manage_backend_package = true,
   $backend_package_ensure = present,
   $connection             = $::os_service_default,
   $slave_connection       = $::os_service_default,
@@ -135,36 +140,38 @@ define oslo::db(
     validate_re($connection,
       '^(sqlite|mysql(\+pymysql)?|postgresql|mongodb):\/\/(\S+:\S+@\S+\/\S+)?')
 
-    case $connection {
+    if $manage_backend_package {
-      /^mysql(\+pymysql)?:\/\//: {
+      case $connection {
-        require '::mysql::bindings'
+        /^mysql(\+pymysql)?:\/\//: {
-        require '::mysql::bindings::python'
+          require '::mysql::bindings'
-        if $connection =~ /^mysql\+pymysql/ {
+          require '::mysql::bindings::python'
-          $backend_package = $::oslo::params::pymysql_package_name
+          if $connection =~ /^mysql\+pymysql/ {
-        } else {
+            $backend_package = $::oslo::params::pymysql_package_name
+          } else {
+            $backend_package = false
+          }
+        }
+        /^postgresql:\/\//: {
           $backend_package = false
+          require '::postgresql::lib::python'
+        }
+        /^mongodb:\/\//: {
+          $backend_package = $::oslo::params::pymongo_package_name
+        }
+        /^sqlite:\/\//: {
+          $backend_package = $::oslo::params::sqlite_package_name
+        }
+        default: {
+          fail('Unsupported backend configured')
         }
       }
-      /^postgresql:\/\//: {
-        $backend_package = false
-        require '::postgresql::lib::python'
-      }
-      /^mongodb:\/\//: {
-        $backend_package = $::oslo::params::pymongo_package_name
-      }
-      /^sqlite:\/\//: {
-        $backend_package = $::oslo::params::sqlite_package_name
-      }
-      default: {
-        fail('Unsupported backend configured')
-      }
-    }
 
-    if $backend_package and !defined(Package[$backend_package]) {
+      if $backend_package and !defined(Package[$backend_package]) {
-      package { $backend_package:
+        package { $backend_package:
-        ensure => $backend_package_ensure,
+          ensure => $backend_package_ensure,
-        name   => $backend_package,
+          name   => $backend_package,
-        tag    => 'openstack',
+          tag    => 'openstack',
+        }
       }
     }
   }

spec/defines/oslo_cache_spec.rb

@@ -75,6 +75,18 @@ describe 'oslo::cache' do
           :tag    => 'openstack',
         )
       end
+
+      context 'with backend package management disabled' do
+        before do
+          params.merge!({
+            :manage_backend_package => false,
+          })
+        end
+
+        it 'does not install backend package' do
+          is_expected.not_to contain_package('python-pylibmc')
+        end
+      end
     end
 
     context 'with memcache backend' do
@@ -91,6 +103,18 @@ describe 'oslo::cache' do
           :tag    => ['openstack'],
         )
       end
+
+      context 'with backend package management disabled' do
+        before do
+          params.merge!({
+            :manage_backend_package => false,
+          })
+        end
+
+        it 'does not install backend package' do
+          is_expected.not_to contain_package('python-memcache')
+        end
+      end
     end
 
     context 'with string in list parameters' do

spec/defines/oslo_db_spec.rb

@@ -89,6 +89,18 @@ describe 'oslo::db' do
           :tag    => 'openstack'
         )
       end
+
+      context 'with backend package management disabled' do
+        before do
+          params.merge!({
+            :manage_backend_package => false,
+          })
+        end
+
+        it 'does not install backend package' do
+          is_expected.not_to contain_package('python-pymongo')
+        end
+      end
     end
 
     context 'with specific mongodb connection string' do
@@ -117,6 +129,18 @@ describe 'oslo::db' do
       it 'install the proper backend package' do
         is_expected.to contain_package('python-psycopg2').with(:ensure => 'present')
       end
+
+      context 'with backend package management disabled' do
+        before do
+          params.merge!({
+            :manage_backend_package => false,
+          })
+        end
+
+        it 'does not install backend package' do
+          is_expected.not_to contain_package('python-psycopg2')
+        end
+      end
     end
 
     context 'with incorrect database_connection string' do
@@ -149,6 +173,18 @@ describe 'oslo::db' do
           :tag    => 'openstack'
         )
       end
+
+      context 'with backend package management disabled' do
+        before do
+          params.merge!({
+            :manage_backend_package => false,
+          })
+        end
+
+        it 'does not install backend package' do
+          is_expected.not_to contain_package('python-pymysql')
+        end
+      end
     end
 
     context 'with sqlite backend' do
@@ -163,6 +199,18 @@ describe 'oslo::db' do
           :tag    => 'openstack'
         )
       end
+
+      context 'with backend package management disabled' do
+        before do
+          params.merge!({
+            :manage_backend_package => false,
+          })
+        end
+
+        it 'does not install backend package' do
+          is_expected.not_to contain_package('python-pysqlite2')
+        end
+      end
     end
   end