Upgrading and Deploying GQuick Code

Several people have gone through the sample application from GQuick using more recent versions of Grails (1.2 and 1.2.1), and it all seems to work, with one exception. If you use packages, as Grails 1.2 and above encourage you to do, one of the plugins (the Blurb plugin) will fail. I've been in contact with the plugin's author and he promises to fix that soon.

On the other hand, if you didn't build the TekDays application but would like to work with the code downloaded from the Pragmatic Programmer's website, there is a different issue. I recently downloaded the final code base, which is found in the download bundle at code/deploy/TekDays/, and upgraded it to Grails 1.2.1. I ran into a conflict with two versions of the Bubbling plugin. It appears that the upgrade process pulls down the newer version of the Bubbling plugin (2.1.1), but the old version (1.5.1) was still installed. The solution (or at least a solution) was to go to home/.grails/1.2.1/projects/TekDays/plugins/and remove the 1.5.1 version of the plugin. After that it all worked fine.

It worked fine, that is, until I tried to deploy the app to Tomcat. When I built the .war file and copied it to my /webapps/ directory, it wouldn't start. I tried forcing it to start from the Tomcat manager. No dice. So I checked in /logs/catalina.out (if you're using Tomcat, you gotta love that file), and found a datasource error that made me smack my forehead.

In the last chapter of GQuick, we look at how to configure a Grails application to use a JNDI datasource, which is a good idea for a real production deployment. But you may not have JDNI configured on your local Tomcat instance; I sure didn't. So, I changed my grails-app/conf/DataSource.groovy file to make the production datasource the same as development.

If you are doing this for the first time and haven't worked through the book, you will need to create a MySQL database called tekdays and set the user and password to match that in the DataSource.groovy file (or vice versa). Alternatively, you can use any database with a JDBC driver. Just include your JDBC driver in the TekDays/grails-app/lib/ directory and modify your DataSource.groovy accordingly. I prefer MySQL because it's so easy to get and easy to use. (More info on MySQL can be found at http://dev.mysql.com.)

One final note: Some people have mentioned getting OutOfMemoryErrors when deploying the app to Tomcat. This can happen with any Grails app if the JVM memory settings are too low. To prevent this, you can add (or modify) a JAVA_OPTS environment variable. In Linux/Unix or Mac OSX, you could do something like this:

export JAVA_OPTS='-Xmx1G -XX:MaxPermSize=256m'

In Windows, you can use the wizard in the control panel under System. Or maybe you can edit your autoexec.bat file. (Do they still use that?)

For the best learning experience, it's probably worth the time to go through the book and build the app as you go, but if you want to just download it and take it for a spin first, these tips should help you get going.

Have fun!