Grails 3 Interceptors as a plugin

Question

I'm trying to convert a Grails 2 controller filter into a Grails 3 interceptor. The interceptor is in a Grails plugin. The Grails 3 upgrade is done, and when I copy and paste the code into an app (just to verify it works), then I see the output from the interceptor.

However, if I try to pull in that code through a plugin to the app, the interceptors do not run. I can verify that the plugin is being pulled; its interceptors are just not being invoked when I hit an action.

For example if the plugin is:

// If added to app directly, works fine. As plugin, not invoked.
class SimpleInterceptor {
    SimpleInterceptor() {
        matchAll()
    }

    boolean before() {
      println 'test' // Does not print if using plugin
    }
}

And the controller is a simple action:

def index() {
   render 'success'
}

Do I need to register it somehow in order for the interceptor to work on apps? Am I missing a step?

Answer 1

Thanks to @vahid for pointing out a repo that was doing something similar. Turns out the issue I had was when I upgraded my plugin's *Plugin.groovy file, I didn't extend grails.plugins.Plugin. Be sure to do that, or the plugin may not get picked up by apps.