Auto-generated TypeScript service definition does not work with addService

[jsholzer]

I recently started checking out gRPC and wanted to implement a basic client and server in TypeScript. This ultimately led me to the @grpc/proto-loader package. When generating the TypeScript typings for the service/proto, the service definition interface that was generated was incompatible with the grpc.Server.addService method. I'm currently using a protobuf service based on the "helloworld" example from the official gRPC repo.

Problem description

The service definition interface generated by the proto-loader-gen-types utility is incompatible with the addService method of the gRPC server instance.

The error given by the TypeScript compiler, in my case, is as follows:

Argument of type 'GreeterDefinition' is not assignable to parameter of type 'ServiceDefinition<UntypedServiceImplementation>'.
  Index signature is missing in type 'GreeterDefinition'.ts(2345)

Protobuf service definition (helloworld.proto):

syntax = "proto3";

package helloworld;

// The greeting service definition.
service Greeter {
  // Sends a greeting
  rpc SayHello (HelloRequest) returns (HelloReply) {}

  // Sends another greeting
  rpc SayHelloAgain (HelloRequest) returns (HelloReply);
}

// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string message = 1;
}

Auto-generated service definition interface:

export interface GreeterDefinition {
  SayHello: MethodDefinition<_helloworld_HelloRequest, _helloworld_HelloReply, _helloworld_HelloRequest__Output, _helloworld_HelloReply__Output>
  SayHelloAgain: MethodDefinition<_helloworld_HelloRequest, _helloworld_HelloReply, _helloworld_HelloRequest__Output, _helloworld_HelloReply__Output>
}

I was able to resolve the issue by manually modifying the service definition interface, extending grpc.ServiceDefinition, as follows:

export interface GreeterDefinition extends grpc.ServiceDefinition {
  ...
}

Reproduction steps

1. Use the proto-loader-gen-types utility to generate typings:

$(npm bin)/proto-loader-gen-types --longs=String --enums=String --defaults --oneofs --grpcLib=@grpc/grpc-js --outDir=proto/ proto/helloworld.proto

2. Use the auto-generated typings to create a gRPC server

import * as grpc from "@grpc/grpc-js";
import * as protoLoader from "@grpc/proto-loader";
import { ProtoGrpcType } from "./proto/helloworld";
import { GreeterHandlers } from './proto/helloworld/Greeter';
import { HelloRequest } from "./proto/helloworld/HelloRequest";
import { HelloReply } from "./proto/helloworld/HelloReply";

const greeterServer: GreeterHandlers = {
    SayHello(call: grpc.ServerUnaryCall<HelloRequest, HelloReply>, callback: grpc.sendUnaryData<HelloReply>)
    {
        callback(null, {message: `Hello ${call.request.name}`});
    },

    SayHelloAgain(call: grpc.ServerUnaryCall<HelloRequest, HelloReply>, callback: grpc.sendUnaryData<HelloReply>)
    {
        callback(null, {message: `Hello again ${call.request.name}`});
    }
}

const PROTO_PATH = `${__dirname}/proto/helloworld.proto`;
const packageDefinition = protoLoader.loadSync(PROTO_PATH);
const proto = (grpc.loadPackageDefinition(packageDefinition) as unknown) as ProtoGrpcType;
const server = new grpc.Server();

server.addService(proto.helloworld.Greeter.service, greeterServer);
server.bindAsync("0.0.0.0:50051", grpc.ServerCredentials.createInsecure(), (err, port) => {
    if (err) throw err;
    
    console.log(`Server started, listening on port ${port}`);
    server.start();
});

Environment

• Windows 10 64-bit
• Node version 14.16.1
• @grpc/grpc-js version 1.2.12
• @grpc/proto-loader version 0.6.1

[gtolarc]

Does not work on grpc other than @grpc/grpc-js.

• @grpc/proto-loader: 0.6.2 (No problem in version 0.6.1)
• grpc: 1.24.10

[murgatroid99]

What exactly are you trying to do, and what error are you getting?

[gtolarc]

In 0.6.1, it was created as 'export interface AuthDefinition {'.

[murgatroid99]

What is the error? That doesn't show any error.

[gtolarc]

What is the error? That doesn't show any error.

really??

[murgatroid99]

Oh, I'm sorry, I didn't see that that error message was separate from the type definition information. I will look into fixing that.

[murgatroid99]

This has been fixed in grpc version 1.24.11.