Idea doesn't upgrade sources while in local debug for appEngine app

Question

I created Spring Boot + Google App Engine application. For development purpose I use IntelliJ IDEA and Google Cloud Tools plugin. I'm currently using only localDebug, which means I don't deploy anything on Google cloud. The configuration for debug is below:

I created a simple service to be sure if my code is updated on change or not:

static int i = 10;
@GetMapping(value = "/test")
public String test() {
    return Integer.toString(++i);
}

Unfortunately when I change my code (e.g. from i = 10 to i = 100) and restart the app (I mean press on Rerun (Ctrl+F5) or Stop (Ctrl+F2) + Run my code doesn't apply on server, which means Idea doesn't rebuild the sources on server start. As you see on the screenshot above I even tried to add Build Project step to Before launch, which didn't work.

• So to apply changes I need to execute from command line mvn appengine:run -> press Ctrl+C to stop it, switch to IDEA and start debug again which is a pain in the ass.
• Another option is to use Hot Reload (Update application, Ctrl+F10). It recompiles only changed classes and reloads resources. This is a cool feature, but unfortunately it doesn't work in a lot of cases which makes me unable to use it as a reliable reload.

Is there anything I can do to force IDEA compile my sources? Is it a bug I should report to plugin developer. Or maybe appengine uses some additional remote sources that require explicit call of maven?

Answer 1

I finally found a solution. As I understood the Google cloud plugin just complies the classes into target/classes but when it starts the appEngine, the engine expected unpacked .war to be present under target/demo-0.0.1-SNAPSHOT.

E.g. if because if I delete both directories I get the error below:

To solve the issue I needed to compile those sources:

• In toolbar Run -> Edit configuration
• Select Google App Engine Standard Local server
• In before launch add Build Artifact -> demo:war exploded where demo is the name of your App.