How to Use Bidirectional Streaming RPC in Go

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2026-04-17T12:05:42+00:00
Implement bidirectional streaming RPC in Go by defining server and client methods that loop through Send and Recv calls on the generated stream interface.

Bidirectional streaming RPC in Go is implemented by defining a server and client that both implement the Server and Client interfaces generated from your .proto file, then using Send and Recv methods on the returned stream within a loop.

// Server implementation
func (s *server) BidirectionalStream(stream proto.MyService_BidirectionalStreamServer) error {
    for {
        msg, err := stream.Recv()
        if err == io.EOF {
            return nil
        }
        if err != nil {
            return err
        }
        if err := stream.Send(&proto.Response{Value: msg.Value * 2}); err != nil {
            return err
        }
    }
}

// Client usage
stream, err := client.BidirectionalStream(ctx)
if err != nil {
    log.Fatal(err)
}

// Send messages in a separate goroutine
for _, req := range requests {
    if err := stream.Send(&proto.Request{Value: req}); err != nil {
        log.Fatal(err)
    }
}
stream.CloseSend()

// Receive responses
for {
    resp, err := stream.Recv()
    if err == io.EOF {
        break
    }
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println(resp.Value)
}