Can we have multiple Grpc services in the Grpc server for the same Protobuf file?

Question

I have an ASP.NET Core 6 Web Api application.

I have a Grpc Client and a Grpc Server.

I have a proto file:

service FooService {
   rpc GetFirstData (FirstRequest) returns (FirstResult);
   rpc GetAnotherData (AnotherRequest) returns (AnotherResult);
}

In the Grpc Client I have 2 services which take FooClient as a parameter. The first service sends GetFirstData request and the second Service sends GetAnotherData request to the Grpc Server. There are no issues here.

With the server, however, if I try to add 2 services, I get a Server Error 500.

public class FirstServerService : Protos.FooService.FooServiceBase
{
    public override Task<FirstResult> GetFirstData (FirstRequest request, ServerCallContext context)
    {
    }
}

public class AnotherServerService : Protos.FooService.FooServiceBase
{
    public override Task<AnotherResult> GetAnotherData (AnotherRequest request, ServerCallContext context)
    {
    }
}

The question is: Is it possible to have multiple services on the backend implementing methods from the same Proto file?

Lol I was just looking for the answer and you asked it 6 hours ago. Exactly what I'd like to achieve and group them somehow so they have different endpoints for gRPC Web like /impl1/FooService and /impl2/FooService — Konrad, Aug 29 '22 at 15:52
Maybe using `RequireHost` and listening on different ports for each implementation e.g. FirstService listens on 5500 and the other on 5501... would work... — Konrad, Aug 29 '22 at 16:01
The only way to possibly achieve this would be some sort of custom server implementation I think. Either listen on different ports like Konrad said, or map the endpoints manually. As soon as you register them with *MapGrpcService* you essentially register the same service base twice on the same endpoint, which causes the error — dan-kli, Sep 01 '22 at 13:48

score 0 · Answer 1 · answered Sep 12 '22 at 20:12

In the Grpc Client you must have two server endpoints defined in appsettins.json or hardcoded as parameters when adding client services in dependency injection in Program.cs such as:

builder.Services.AddSingleton<IFirstClient>(p => new FirstClient(builder.Configuration["GrpcServerUrl1"]));
builder.Services.AddSingleton<ISecondClient>(p => new SecondClient(builder.Configuration["GrpcServerUrl2"]));

now each client service in your Grpc Client program will be reached to different grpc server.

Can we have multiple Grpc services in the Grpc server for the same Protobuf file?

1 Answers1