Build and debug GWT applications on a remote system using SSH port forwarding

Originally posted on 2020-11-06

Sometimes my local machine is just too slow to build and iterate on some code. When this happens I like to fire up a cloud instance with beefy specs and do my builds there.

With GWT and SSH port forwarding I can build my code on a fast machine and even access super dev mode. I set up a shell script that syncs my code with rsync to the instance so I use IntelliJ locally, sync my code, refresh my browser and see the changes very quickly.

To set up SSH port forwarding for GWT I use this command:

ssh -L 8080: -L 9876: user@ip

This forwards Jetty (port 8080) and the GWT code server (port 9876) back to your system on localhost. Then I open up my localhost debug URL as normal (e.g. http://localhost:8080/appname) and everything just works.

One caveat is that on the remote machine I usually need to do a full build first to make sure the initial HTML and JavaScript files are in place for Jetty. Otherwise I may get a blank screen and an error from my GWT bookmarklets that says no modules are on the page.

What does my syncing script look like? Check out my Optimized rsync setup for GWT + AWS CDK projects.