db: Use postgresql lib class for psycopg package

This patch introduce the same design than mysql for postgresql
by requiring dedicated lib::python class instead of declaring
a new resource package within sahara module.

Change-Id: I1c9378fb9aba2b4261ab25f4057cccf71560d1a8

manifests/db.pp

@@ -62,7 +62,7 @@ class sahara::db (
       require mysql::bindings::python
     }
     /^postgresql:\/\//: {
-      $backend_package = $::sahara::params::psycopg_package_name
+      $backend_package = false
       require postgresql::lib::python
     }
     default: {

manifests/params.pp

@@ -15,7 +15,6 @@ class sahara::params {
       $all_service_name     = 'openstack-sahara-all'
       $api_service_name     = 'openstack-sahara-api'
       $engine_service_name  = 'openstack-sahara-engine'
-      $psycopg_package_name = 'python-psycopg2'
     }
     'Debian': {
       $common_package_name  = 'sahara-common'
@@ -25,7 +24,6 @@ class sahara::params {
       $all_service_name     = 'sahara'
       $api_service_name     = 'sahara-api'
       $engine_service_name  = 'sahara-engine'
-      $psycopg_package_name = 'python-psycopg2'
     }
     default: {
       fail("Unsupported osfamily: ${::osfamily} operatingsystem: ${::operatingsystem}")

spec/classes/sahara_db_spec.rb

@@ -34,6 +34,17 @@ describe 'sahara::db' do
       it { is_expected.to contain_sahara_config('database/max_overflow').with_value('21') }
     end
 
+    context 'with postgresql backend' do
+      let :params do
+        { :database_connection     => 'postgresql://sahara:sahara@localhost/sahara', }
+      end
+
+      it 'install the proper backend package' do
+        is_expected.to contain_package('python-psycopg2').with(:ensure => 'present')
+      end
+
+    end
+
     context 'with incorrect database_connection string' do
       let :params do
         { :database_connection     => 'sqlite://sahara:sahara@localhost/sahara', }
@@ -45,7 +56,10 @@ describe 'sahara::db' do
 
   context 'on Debian platforms' do
     let :facts do
-      { :osfamily => 'Debian' }
+      { :osfamily => 'Debian',
+        :operatingsystem => 'Debian',
+        :operatingsystemrelease => 'jessie',
+      }
     end
 
     it_configures 'sahara::db'
@@ -53,7 +67,9 @@ describe 'sahara::db' do
 
   context 'on Redhat platforms' do
     let :facts do
-      { :osfamily => 'RedHat' }
+      { :osfamily => 'RedHat',
+        :operatingsystemrelease => '7.1',
+      }
     end
 
     it_configures 'sahara::db'