Allow to set ProxyPassReverse attributes on a vhost

This commit allows you to add an array or a string as a proxy_pass['reverse_url']
parameter.

Useful when used with mod_balancer.

README.md

@@ -991,10 +991,14 @@ apache::vhost { 'site.name.fdqn':
     { 'path' => '/a', 'url' => 'http://backend-a/' },
     { 'path' => '/b', 'url' => 'http://backend-b/' },
     { 'path' => '/c', 'url' => 'http://backend-a/c' },
+    { 'path' => '/l', 'url' => 'http://backend-xy',
+      'reverse_urls' => ['http://backend-x', 'http://backend-y'] },
   ],
 }
 ```
 
+`reverse_urls` is optional and can be an array or a string. It is useful when used with `mod_proxy_balancer`.
+
 #####`rack_base_uris`
 
 Specifies the resource identifiers for a rack configuration. The file paths specified will be listed as rack application roots for [Phusion Passenger](http://www.modrails.com/documentation/Users%20guide%20Apache.html#_railsbaseuri_and_rackbaseuri) in the _rack.erb template. Defaults to 'undef'.

spec/defines/vhost_spec.rb

@@ -389,6 +389,33 @@
           ],
           :notmatch => [/ProxyPass .+!$/],
         },
+        {
+          :title    => 'should accept reverse_urls string',
+          :attr     => 'proxy_pass',
+          :value    => { 'path' => '/path-a', 'url' => 'http://fake.com/a', 'reverse_urls' => 'http://127.0.0.1:8080' },
+          :match    => [
+            /^  ProxyPass \/path-a http:\/\/fake.com\/a$/,
+            /^  <Location \/path-a>$/,
+            /^    ProxyPassReverse http:\/\/127.0.0.1:8080$/,
+            /^  <\/Location>$/,
+
+          ],
+          :notmatch => [/^    ProxyPassReverse http:\/\/fake.com\/a$/],
+        },
+        {
+          :title    => 'should accept reverse_urls array',
+          :attr     => 'proxy_pass',
+          :value    => { 'path' => '/path-a', 'url' => 'http://fake.com/a', 'reverse_urls' => ['http://127.0.0.1:8080', 'http://127.0.0.1:8081'] },
+          :match    => [
+            /^  ProxyPass \/path-a http:\/\/fake.com\/a$/,
+            /^  <Location \/path-a>$/,
+            /^    ProxyPassReverse http:\/\/127.0.0.1:8080$/,
+            /^    ProxyPassReverse http:\/\/127.0.0.1:8081$/,
+            /^  <\/Location>$/,
+
+          ],
+          :notmatch => [/^    ProxyPassReverse http:\/\/fake.com\/a$/],
+        },
         {
           :title    => 'should accept proxy_pass array of hash',
           :attr     => 'proxy_pass',

templates/vhost/_proxy.erb

@@ -9,7 +9,13 @@
 <%- [@proxy_pass].flatten.compact.each do |proxy| -%>
   ProxyPass <%= proxy['path'] %> <%= proxy['url'] %>
   <Location <%= proxy['path']%>>
+  <%- if proxy['reverse_urls'].nil? -%>
     ProxyPassReverse <%= proxy['url'] %>
+  <%- else -%>
+    <%- Array(proxy['reverse_urls']).each do |reverse_url| -%>
+    ProxyPassReverse <%= reverse_url %>
+    <%- end -%>
+  <%- end -%>
   </Location>
 <% end %>
 <% if @proxy_dest -%>