gRPC server in a WorkerService

A few days ago, I was working on a client-server application where I was going to use Sockets to establish communication. But then I had the idea that I could use gRPC, which would expand the range of possible clients. Plus, it would serve as a learning experience for me to use gRPC.

The first surprise was that Visual Studio only offers a gRPC template that requires an ASP.Net server. So, I decided to do some research since my application would use a WorkerService that would likely run as a Docker image.

After doing a little research, I decided to start testing, and this is the result.

Server

The first step is to generate a WorkerService application in Visual Studio. Then, the following Nuget packages in their most updated version should be added:

<PackageReference include="Grpc" version="2.46.6">
<PackageReference include="Google.Protobuf" version="3.22.1">
<PackageReference Include="Grpc.Tools" Version="2.53.0">
            <PrivateAssets>all</PrivateAssets>
            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>        </PackageReference>

Next, we will create a folder called Protos or Proto, whichever you prefer. And a new .proto file with the service definition.

We will add this file to the project.

<ItemGroup>
        <Protobuf Include="Proto\my_file.proto" />
</ItemGroup>

syntax = "proto3";

import "google/protobuf/empty.proto";

option csharp_namespace = "GrpcServer";

message CommandRequest {
  int32 id = 1;
  string params = 2;
}

message CommandResponse {
  string message = 1;
}

service CommsService {
  rpc SendCommand (CommandRequest) returns (CommandResponse);
}

Next, we create the class to manage the service.

public partial class CommsService : SysmacGrpcServer.CommsService.CommsServiceBase {
    public override Task<CommandResponse> SendCommand(CommandRequest request, ServerCallContext context) {
        CommandResponse response = new CommandResponse() {Message = "Message received"};
        return Task.FromResult(response);
    }
}

As a final step, we will start the server in the WorkerService.

public class SysmacWorker : BackgroundService {
    private readonly Server _server;

    public SysmacWorker(CommsService commService) {
        _commsService = commService;
        _server = new Server {
            Services = { SysmacGrpcServer.CommsService.BindService(_commsService) },
            Ports = { new ServerPort("localhost", 50051, ServerCredentials.Insecure) }
        };
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken) {
        _server.Start();
        await Task.Delay(100, stoppingToken);
    }
}