How to determine if a play app is running on a worker dyno on heroku?

Question

I have a play 1.2.5 app running on heroku and I want to swap out all jobs into a worker dyno, so they don't scale with the web dynos.

To do that, I need to differentiate, if the application is running on a web or a worker dyno.

Is there any way to accomplish that by passing a command line argument using the procfile?

Currently I see, that by passing custom CLI arguments the JVM fails to be created...

Thanks you in advance!

Answer 1

Okay, I found it myself:

By adding a -D parameter to the procfile, I can determine the environment play is running in.

So my procfile's going to look like:

web: play run --http.port=$PORT $PLAY_OPTS
worker: play run --http.port=$PORT $PLAY_OPTS -Dprocesstype=worker

By using

System.getProperty("processtype");

I can ensure, that i am on a worker dyno and process my jobs only then.