Netty conflicts of gRPC and Lagom

I would like to use both Google Cloud Java library and Lagom. Both gRPC (dependency of Google Cloud Java) and Lagom use Netty but not the same version which cause conflicts and error while booting up: Caused by: java.lang.NoClassDefFoundError: Could not initialize class io.netty.handler.ssl.OpenSslEngine

Lagom Version (1.2.x / 1.3.x / etc)

Everything works fine on Lagom 1.4.-M3 but problem persists on all other gPRC.

[TimMoore]

@idoshamun thank you for the example project… that’s a big help!

The configuration error is happening because there is still a definition for lagom-gcp-demo-stream-impl in build.sbt, but the files have been removed. You can comment out or delete that definition to fix the error.

Also, as a testing note for anyone else trying to reproduce. You need to specify a Google Cloud project ID for the service to start. Running GOOGLE_CLOUD_PROJECT=test sbt runAll was enough to get me past that error.

Once it’s running, open another terminal and run curl http://localhost:9000/api/hello. This succeeds, but also logs a stack trace in the runAll console with the Netty error.

[TimMoore]

Great to hear @idoshamun. I’ll close this issue, because I don’t think there’s any good way to prevent this from happening at the framework level.