Client side error handling with Micronaut

Question

I am using a Micronaut layer between a REST service and a consumer app. |REST service|->|Micronaut client / controller|->|consumer app|. When the REST service is returning an error, the controller should propagate the error code. When the REST service is offline, the controller should return some kind of 500 error code. However, right now it's returning an empty body with a 200 error code in both cases.

For the example here is my controller:

@Controller("/api/v1") 
public class MyController {

private final ClientNetworkList clientNetworkList;

public MyController( 
    ClientNetworkList clientNetworkList,
){
    this.clientNetworkList = clientNetworkList;
}

    @Get(uri = "/networkList", produces = MediaType.APPLICATION_JSON_STREAM)
    Flowable<NetworkListPackage> packagesNetworkList() { 
        return clientNetworkList.fetchPackages();
    }
}

And the client:

@Client(FabricConfiguration.FABRIC_API_URL) 
public interface ClientNetworkList{
     @Get("/auth/networklist") 
    Flowable<NetworkListPackage> fetchPackages();   
}

How can I propagate or throw the correct body and error code? How should I use the @Error annotation, should it be implemented in the controller or in a filter?

Answer 1

Micronaut has a Circuit Breaker Support for such things.

I would recommend to use the @Fallback Annotation and throw an Exception which will produce the 500 Error Code. See 7.3.7 Client Fallback in Micronaut Documentation.