grpc server not working in docker-compose

Question

I build sample project with grpc server.in vs every things is ok and my project nice worked. dokcer-compose.yaml is :

version: '3.3' 
services:
  grpcService:
    container_name: grpcserver
    image:  grpcImage
    ports:
      - "5003:5003"  //client
      - "5001:5001"  //grpc server
    restart: always

in project I set http://127.0.0.1:5001 for grpc server

and set http://127.0.0.1:5003 for client I handle (grpc server worked with http)

when docker-compose up and call api ,get faild and grpc server not found , etc

Answer 1

you must change CreateHostBuilder to this code in program.cs Grpc Server

public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup<Startup>().ConfigureKestrel(options =>
                {
                    options.Listen(IPAddress.Any, 5001, listenOptions =>
                    {
                        listenOptions.Protocols = HttpProtocols.Http2;
                    });
                });
            });
}

5001 is grpc Server Port.(change this port to your grpc server port)

Answer 2

It's not entirely clear from your question how your client and server are separated; I would usually expect to see 2 services in the Docker Compose file: one for the server and a second for the client.

It is probable (!) that your client is unable to connect to the server because you are using the loopback (127.0.0.1) address. Loopback is a short-circuit way to route traffic within a machine that may not use the machine's network stack. For this reason, loopback traffic is not exposed beyond the container and is thus inaccessible to your client.

It is better to use 0.0.0.0 as the server's address when you run (!) the server so that the server will be bound to the networking stack and can be used by the host and other services (containers). In your Docker Compose file, this service will be given the DNS name of grpcService (probably lowercase only!?) and can be accessed from another service running in the Docker Compose file (network) as grpcservice:5003.

NOTE With the Docker Compose file (and its network), the server will be bound to whatever port you run it as e.g. 5003. The ports: - "XXXX:5003" is redundant *unless you wish to access this service from the host machine (outside of the Docker Compose network) when it will be available on port XXXX.