Update exim module to work on RHEL.

Parameterizes the exim module so that it can support multiple
distributions.

As part of this patch I also removed the explicit install
of exim4-base and exim4-config on Ubuntu. Just installing
exim4-daemon-light should be fine.

Change-Id: Ie09c5fa01509ebfadc92b8540f04181a2b13b667
Reviewed-on: https://review.openstack.org/23289
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Monty Taylor <mordred@inaugust.com>
Approved: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins

modules/exim/manifests/init.pp

@@ -2,31 +2,29 @@ class exim(
   $mailman_domains = [],
   $sysadmin = []
 ) {
-  package { 'exim4-base':
+
+  include exim::params
+
+  package { $::exim::params::package:
     ensure => present,
   }
 
-  package { 'exim4-config':
+  if ($::operatingsystem == 'Redhat') {
-    ensure => present,
+    service { 'postfix':
+      ensure      => stopped
+    }
   }
 
-  package { 'exim4-daemon-light':
+  service { 'exim':
-    ensure  => present,
-    require => [
-      Package[exim4-base],
-      Package[exim4-config]
-    ],
-  }
-
-  service { 'exim4':
     ensure      => running,
+    name        => $::exim::params::service_name,
     hasrestart  => true,
-    subscribe   => File['/etc/exim4/exim4.conf'],
+    subscribe   => File[$::exim::params::config_file],
   }
 
-  file { '/etc/exim4/exim4.conf':
+  file { $::exim::params::config_file:
     ensure  => present,
-    content => template('exim/exim4.conf.erb'),
+    content => template("${module_name}/exim4.conf.erb"),
     group   => 'root',
     mode    => '0444',
     owner   => 'root',
@@ -35,7 +33,7 @@ class exim(
 
   file { '/etc/aliases':
     ensure  => present,
-    content => template('exim/aliases.erb'),
+    content => template("${module_name}/aliases.erb"),
     group   => 'root',
     mode    => '0444',
     owner   => 'root',

modules/exim/manifests/params.pp

@@ -0,0 +1,23 @@
+# Class: exim::params
+#
+# This class holds parameters that need to be
+# accessed by other classes.
+class exim::params {
+  case $::osfamily {
+    'Redhat': {
+      $package = 'exim'
+      $service_name = 'exim'
+      $config_file = '/etc/exim/exim.conf'
+      $conf_dir = '/etc/exim/'
+    }
+    'Debian', 'Ubuntu': {
+      $package = 'exim4-daemon-light'
+      $service_name = 'exim4'
+      $config_file = '/etc/exim4/exim4.conf'
+      $conf_dir = '/etc/exim4'
+    }
+    default: {
+      fail("Unsupported osfamily: ${::osfamily} The 'exim' module only supports osfamily Ubuntu or Redhat(slaves only).")
+    }
+  }
+}

modules/exim/templates/exim4.conf.erb

@@ -37,7 +37,8 @@
 #                                                                          #
 ########### IMPORTANT ########## IMPORTANT ########### IMPORTANT ###########
 
-CONFDIR = /etc/exim4
+CONFDIR = <%= scope.lookupvar('exim::params::conf_dir') %>
+
 
 ######################################################################
 #                    MAIN CONFIGURATION SETTINGS                     #