Use caching reverse proxy for rdo repos

We can't sanely mirror the rdo packages beacuse they are constantly
updating. Instead put a caching reverse proxy in front of the repos in
each region on our existing mirror servers. This should allow us to get
region local data that is "hot" and hopefully improve reliability to the
rdo repos.

Change-Id: I6ab810f7b6788459da1cee00baf6b053f31843cf

modules/openstack_project/manifests/mirror.pp

@@ -202,6 +202,14 @@ class openstack_project::mirror (
   # Build VHost
   include ::httpd
 
+  file { '/opt/apache_cache':
+    ensure => directory,
+    owner  => 'www-data',
+    group  => 'www-data',
+    mode   => '0755',
+    require => Class['httpd']
+  }
+
   if ! defined(Httpd::Mod['rewrite']) {
     httpd::mod { 'rewrite':
       ensure => present,
@@ -214,6 +222,24 @@ class openstack_project::mirror (
     }
   }
 
+  if ! defined(Httpd::Mod['cache']) {
+    httpd::mod { 'cache':
+      ensure => present,
+    }
+  }
+
+  if ! defined(Httpd::Mod['cache_disk']) {
+    httpd::mod { 'cache_disk':
+      ensure => present,
+    }
+  }
+
+  if ! defined(Httpd::Mod['proxy']) {
+    httpd::mod { 'proxy':
+      ensure => present,
+    }
+  }
+
   ::httpd::vhost { $vhost_name:
     port     => 80,
     priority => '50',

modules/openstack_project/templates/mirror.vhost.erb

@@ -81,4 +81,23 @@ NameVirtualHost <%= @vhost_name %>:<%= @port %>
     LogLevel warn
     CustomLog /var/log/<%= scope.lookupvar("httpd::params::apache_name") %>/<%= @name %>_access.log combined
     ServerSignature Off
+
+    # Caching reverse proxy for things that don't make sense in AFS
+    #
+    # General cache rules
+    CacheRoot "/opt/apache_cache"
+    CacheDirLevels 5
+    CacheDirLength 3
+    # Prevent thundering herds.
+    CacheLock on
+    CacheLockPath "/tmp/mod_cache-lock"
+    CacheLockMaxAge 5
+    # 100MB
+    CacheMaxFileSize 104857600
+
+    # Per site caching reverse proxy rules
+    # Only cache specific backends, rely on afs cache otherwise.
+    CacheEnable disk  "/rdo"
+    ProxyPass "/rdo" "https://trunk.rdoproject.org/"
+    ProxyPassReverse "/rdo" "https://trunk.rdoproject.org/"
 </VirtualHost>