Skip to main content

Changing ports with Grails

Posted by johnsmart on May 5, 2009 at 12:24 PM PDT

When you run a Grails application from the command line (using grails run-app, for example), it will run on port 8080 by default. This also applies when Grails runs web tests such as Selenium, Canoo webtest or HTMLUnit. If you have web tests in your application, Grails will automatically start up the application before running the tests, which is just what you want.

However, the port 8080 is not always what you want. You may need to run your Grails app on a different port if port 8080 has already been taken by another application. This is particularly the case on build servers, for example. The simplest solution is to set the server.port property on the command line, as shown here:


$ grails run-app -Dserver.port=8888

This is good as far as it goes, but has some limitations. Firstly, what if you always want to use the port 8888 for your Grails apps? Secondly, if you are using Hudson with the Grails plugin, this plugin doesn't currently let you provide command-line options like this. A work-around is to invoke grails from the command line in Hudson, as shown here:


$ grails -Dserver.port=8888 test-app

Note that Grails is finicky about the position of command-line parameters - they need to go after the "grails" command and before the target.

Another solution is to change the default port used by Grails itself. In Grails 1.1 at least, the trick is to modify the $GRAILS_HOME/scripts/_GrailsSettings.groovy file. In it, you will find a reference to the default port (8080). Just change it to whatever you require, and Grails will always run on this new port. The modified entry might look like this:


serverPort = getPropertyValue("server.port", 8888).toInteger()

Once this is done, Grails will always run on this port.


"Probably the best training course I've been on."..."Not just how to write Java code but the 'business end' - how to build, test, deploy, manage and monitor"..."One of the best and most useful courses I have attended. And they didn't even try to sell me anything!" - Coming soon to London! Get up to scratch with the latest in Java tools and best practices! Sign up on the 2009 season of the Java Power Tools Bootcamps.