Avoid dependency cycles with glibc-langpack-en

By calling stdlib::ensure_packages() in the class itself the resource
gets tied to the class. If other packages also depend on the resource,
you can get dependency cycles.

In particular, candlepin also does this and that causes a dependency
cycle.

By using a class that is included the resource "floats" in the catalog.
We then only ensure the package is installed somewhere before we create
the database.

Link: theforeman/puppet-candlepin@ca77145
Fixes: 768a54e ("Ensure glibc-langpack-en is always installed on EL")

Author: ekohl

manifests/database/postgresql.pp

@@ -6,17 +6,14 @@
   }
 
   include postgresql::client, postgresql::server
-
-  if $facts['os']['family'] == 'RedHat' {
-    stdlib::ensure_packages(['glibc-langpack-en'])
-    Package['glibc-langpack-en'] -> Postgresql::Server::Db[$foreman::db_database]
-  }
+  include foreman::database::postgresql::encoding
 
   postgresql::server::db { $foreman::db_database:
     user     => $foreman::db_username,
     password => postgresql::postgresql_password($foreman::db_username, $foreman::db_password),
     owner    => $foreman::db_username,
     encoding => 'utf8',
     locale   => 'en_US.utf8',
+    require  => Class['foreman::database::postgresql::encoding'],
   }
 }

manifests/database/postgresql/encoding.pp

@@ -0,0 +1,7 @@
+# @summary Class to ensure the packages for encoding are installed
+# @api private
+class foreman::database::postgresql::encoding {
+  if $facts['os']['family'] == 'RedHat' {
+    stdlib::ensure_packages(['glibc-langpack-en'])
+  }
+}

spec/classes/foreman_database_spec.rb

@@ -1,11 +1,17 @@
 require 'spec_helper'
 
 describe 'foreman' do
-  on_supported_os.each do |os, facts|
+  on_supported_os.each do |os, os_facts|
     context "on #{os}" do
-      let(:facts) { facts }
+      let(:facts) { os_facts }
       let(:params) { {} }
 
+      if os_facts[:os]['family'] == 'RedHat'
+        it { should contain_package('glibc-langpack-en').that_comes_before('Postgresql::Server::Db[foreman]') }
+      else
+        it { should_not contain_package('glibc-langpack-en') }
+      end
+
       describe 'with db_manage set to false' do
         let(:params) { super().merge(db_manage: false) }