Going live with your Grails app part 1 of X

So I thought I would right up some problem/solutions I had with deploying a Grails app into production.

First step is reducing grails WAR file size.

I have depolyed my latest app http://www.ebookstamper.com on Amazon EC2 (i will do a later step by step post for EC2 deployment). After a few round trips i realised that i was getting pi**ed off with the time it was taking to upload my 20-30meg war file to my server. So after a bit of digging around on the web and some trial and error I devised a way to reduce my WAR size. Here are the steps below:

1) Use Tomcat 6.X
I won't bother giving arguments for using Tomcat 6. Let me just say if you are developing a new app then take it from me this is what you want to be using for your app server. I worked on a large project for the last 12 month getting this website live http://www.carphonewarehouse.com/ and we really squeezed out the performace of Tomcat and the sun JDK1.6 with great results.

2) Set up a shared library in tomcat

Make a directory called shared/lib under tomcat home directory

mkdir -p $TOMCAT_HOME/shared/lib

3) Tell tomcat about this lib

Find the file $TOMCAT_HOME/conf/catalina.properties

Change this line

shared.loader=

to

shared.loader=${catalina.base}/shared/lib,${catalina.base}/shared/lib/*.jar

4) Build your Grails war file

Ok first off you should build your grails war file as normal to get all the jars.

grails war

Or if you going to deploy the app as root context "/" on tomcat do this

grails war ROOT.war

The main point of this exercise is to have grails build a complete WAR file including all the jar librarys you need. These jars come from all over. Grails home/dist, Grails home/lib, plugins and your app lib. So instead of you manually going to find all these jar files just have grails do it for you.

So once you have your WAR file you will have all the jars you need for your app inside the war file in WEB-INF/lib.

5) Copy all the jar files to $TOMCAT_HOME/shared/lib

So unpack the war file and copy all the jar files to the $TOMCAT_HOME/shared/lib directory you created earlier. My simple technique for this was.

a) Upload the ROOT.war file to your server and put it in the $TOMCAT_HOME/webapps directory. This way it is one (a big one) file to upload.

b) Start tomcat and have it deploy your application. This will get tomcat to unpack the war file for you.

c) Stop tomat then go into the unpacked war lib directory $TOMCAT_HOME/webapps/ROOT/WEB-INF/lib and move all the jar files in there to $TOMCAT_HOME/shared/lib. You can then delete the contents of webapps.

6) Next build yourself an empty war file

Now this is the magic bit that i found somewhere out on the web. The --nojars arguement.

grails war --nojars ROOT.war

The --nojars argument will build a grails war file without any jars in the WEB-INF/lib directory in the war file. You should see that this will reduce the war file size by rather pleaseable amount.

7) Redeploy your new lightweight ROOT.war on tomcat
You can then redeploy your new war on tomcat and have a new working app

Next time around you only need to build the war without any jar file.

Now this should be obvious but i will point it out anyway. If you add a new plugin, upgrade grails or add a new lib jar to your app then you should repeat all of this from the start to avoid class not found problems.

Enjoy