I’ve been using Burt Beckwith‘s UI Performance plugin for Grails to bundle and compress my static content (images, js, css) during the build, so I can save on outbound bandwith and improve the response time of my application. In order to take advantage of this build-time optimization, we need to modify the Apache configuration to serve static content instead of proxying those requests to the container.

1. $ grails install-plugin ui-performance
2. Configure your app to use the plugin’s taglibs and to bundle resources if necessary. (See http://www.grails.org/plugin/ui-performance)
3. Add a handler for the CreateWarEnd event in your scripts/Events.groovy file (make one if you don’t have one). This handler will package all the bundled and gzipped resources into a static zip file that you can upload to Cloud Foundry:

   eventCreateWarEnd = {warName, stagingDir ->
       def directory = new File(warName).parent
   
       ant.zip(destfile:"${directory}/static.zip") {
           fileset(dir:"${stagingDir}") {
               include name: "images/**"
               include name: "css/**"
               include name: "js/**"
           }
       }
   }
   

4. Create a “container initialization script” for Cloud Foundry to execute when your instance starts up. This script will tell Apache to directly serve the following directories and to add the appropriate Content-Encoding header for content that is already gzipped. The name doesn’t really matter at this point, but I called mine proxyexcludes.sh.

   cat > /etc/httpd/conf.d/_proxyexcludes.conf <<END
   ProxyPass /images !
   ProxyPass /css !
   ProxyPass /js !
   
   SetEnvIf Request_URI "\\.gz\\.(css|js|jpg|gif|png|ico)\$" already_compressed=true
   Header set Content-Encoding gzip env=already_compressed
   END
   

   I found that keeping this file up to date was easier if I just let grails rebuild it every time after the WAR is created. I modified my eventCreateWarEnd handler to take care of this for me:

   eventCreateWarEnd = {warName, stagingDir ->
       def directory = new File(warName).parent
   
       ant.zip(destfile:"${directory}/static.zip") {
           fileset(dir:"${stagingDir}") {
               include name: "images/**"
               include name: "css/**"
               include name: "js/**"
           }
       }
   
       ant.echo "Creating Proxy exclusion list: ${directory}/proxyexcludes.sh"
       new File("${directory}/proxyexcludes.sh") << """cat > /etc/httpd/conf.d/_proxyexcludes.conf <<END
   ProxyPass /images !
   ProxyPass /css !
   ProxyPass /js !
   
   SetEnvIf Request_URI "\\.gz\\.(css|js|jpg|gif|png|ico)\$" already_compressed=true
   Header set Content-Encoding gzip env=already_compressed
   END
   """
   
   }
   

5. $ grails war
6. Upload the static.zip file produced during the build as “static content” when you upload your app to Cloud Foundry:
   

   Cloud Foundry Upload Static Content

7. When creating a deployment, upload your “proxyexcludes.sh” container initialization script:
   

   Cloud Foundry Deployment

8. Fire up your instance and check out the performance gains!