Frustrated with Grpc-node

[Rob Cecil]

I'm experienced with Grpc - having built iOS/ObjC front-end and C# backend over a two year period (a Grpc project consisting of a main proto with a service that has 27 methods, and about a dozen supporting protos for message definitions).

I am however, not super experienced with web development, so I am a little frustrated atm, trying to get simple things to work with Grpc-node.  I started with something simple - the HelloWorld example and modified it from there. 

Here is my current "test.proto":

syntax = "proto3";


package helloworld;


service Greeter {
    rpc SayHello(FooBarRequest) returns (FooBarReply);
    rpc SayHelp(FooBarRequest) returns (FooBarReply);
}


message FooBarRequest {
    string name = 1;
}
 
message FooBarReply {
    string message = 1;
}

server.js:

const _ = require('lodash');
const grpc = require('grpc');
const protoLoader = require('@grpc/proto-loader');


const argv = require("minimist")(process.argv.slice(2));
console.dir(argv);


if (!argv.h) {
    console.log("Please start server.js with -h xx.xx.xx.xx:xxxx");
    process.exit(1);
}
console.log(`Starting server.js on : ${argv.h}`);


const PROTOS_PATH = __dirname + '/../protos/';
const BESERVICE_PROTO_PATH = PROTOS_PATH + 'test.proto';


const beDefinition = protoLoader.loadSync(
    BESERVICE_PROTO_PATH,
    {keepCase: true,
     longs: String,
     enums: String,
     defaults: true,
     oneofs: true
    });


const test = grpc.loadPackageDefinition(beDefinition).helloworld;


function SayHello(call, callback) {
    callback(null, {message: 'Hello ' + call.request.name});
}


function SayHelp(call, callback) {
    callback(null, {message: 'Help! ' + call.request.name});
}


function main() {
    var server = new grpc.Server();
    server.addService(test.Greeter.service, {
        SayHello: SayHello,
        SayHelp: SayHelp
    });
    server.bind(argv.h, grpc.ServerCredentials.createInsecure());
    server.start();
}
 
main();

client.js:

const grpc = require('grpc');
const util = require('util')
const protoLoader = require('@grpc/proto-loader');
const argv = require("minimist")(process.argv.slice(2));
console.dir(argv);


if (!argv.h) {
    console.log("Please start with -h xx.xx.xx.xx:xxxx");
    process.exit(1);
}
console.log(`Starting Node backend client on : ${argv.h}`);


const PROTOS_PATH = __dirname + '/../protos/';
const BESERVICE_PROTO_PATH = PROTOS_PATH + 'test.proto';


const beDefinition = protoLoader.loadSync(
    BESERVICE_PROTO_PATH,
    {keepCase: true,
     longs: String,
     enums: String,
     defaults: true,
     oneofs: true
    });


const test = grpc.loadPackageDefinition(beDefinition).helloworld;


function main() {
    var client = new test.Greeter(argv.h, grpc.credentials.createInsecure());
   
    client.SayHello({ name: 'Darth' }, {}, (err, response) => {
        if (err) {
            console.error("error calling SayHello", err);
            return
        }
        console.log('Greeting:', response.message);


        client.SayHelp({ name: 'Darth' }, {}, (err, response) => {
            if (err) {
                console.error("error calling SayHelp", err);
                return
            }
            console.log('Help! ', response.message);
        });
    });
  }
 
  main();

I run the client and server on the same machine, using the same command line argument for the same host & port.

Can anyone explain why I get "RPC method not implemented" on the second method defined in the  Greeter service above?

wander@peniche:~/control-web/js$ !1186
node server.js -h 172.16.0.168:9090 &
[1] 57465
wander@peniche:~/control-web/js$ { _: [], h: '172.16.0.168:9090' }
Starting server.js on : 172.16.0.168:9090


wander@peniche:~/control-web/js$ !1187
node backendservice-node-client.js -h 172.16.0.168:9090
{ _: [], h: '172.16.0.168:9090' }
Starting Node backend client on : 172.16.0.168:9090
Greeting: Hello! Darth
error calling SayHelp { Error: 12 UNIMPLEMENTED: RPC method not implemented /helloworld.Greeter/SayHelp
    at Object.exports.createStatusError (/home/wander/control-web/node_modules/grpc/src/common.js:91:15)
    at Object.onReceiveStatus (/home/wander/control-web/node_modules/grpc/src/client_interceptors.js:1204:28)
    at InterceptingListener._callNext (/home/wander/control-web/node_modules/grpc/src/client_interceptors.js:568:42)
    at InterceptingListener.onReceiveStatus (/home/wander/control-web/node_modules/grpc/src/client_interceptors.js:618:8)
    at callback (/home/wander/control-web/node_modules/grpc/src/client_interceptors.js:845:24)
  code: 12,
  metadata: Metadata { _internal_repr: {} },
  details: 'RPC method not implemented /helloworld.Greeter/SayHelp' }

If i remove the SayHelp method in the proto and update the client & server code, it works fine.

THANKS

[Mya Pitzeruse]

On the server side, try using lowercase names instead of title case:

    server.addService(test.Greeter.service, {
        sayHello: SayHello,
        sayHelp: SayHelp
    });

I would assume that using "keepCase: true" meant that they would require these to be the same as the proto. But here's an example where I use the same loader semantic and the same casing: 

https://github.com/mjpitz/des/blob/master/api/extractor.proto#L19

https://github.com/mjpitz/des/blob/master/api/extractor.js#L8

And all of my service methods are use camel case instead of the case I used in the proto file:

https://github.com/mjpitz/des/blob/master/src/service/unasyncify.ts#L9

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[Michael Lumish]

Can you try updating your dependencies? I just tried running the given code with the latest versions of grpc and @grpc/proto-loader and it worked. There was previously an issue that the library would not accept method names with the same casing as in the original proto file, but that was fixed a while ago.

As a side note, the `keepCase` option in `proto-loader` affects message field names. If it is not set, the field names are transformed to camel case.

[Rob Cecil]

I updated everything:

wander@peniche:~/control-web$ npm list --depth=0 2>/dev/null
control-web@0.0.1 /home/wander/control-web
├── @grpc/proto-loader@0.4.0
├── google-protobuf@3.7.0
├── grpc@1.19.0
├── grpc-inspect@0.6.0
├── grpc-web@1.0.3
├── lodash@4.17.11
├── minimist@1.2.0
├── webpack@4.29.6
└── webpack-cli@3.2.3

I still see the same behavior.

If I change my server.,js:

function main() {
    var server = new grpc.Server();
    server.addService(test.Greeter.service, {

        sayHello: SayHello,
        sayHelp: SayHelp
    });

    //console.dir(util.inspect(server,  showHidden=false, depth=5, colorize=false));
    server.bind(argv.h, grpc.ServerCredentials.createInsecure());
    server.start();
}

Restart, ... I see the same behavior.

[Rob Cecil]

https://gist.github.com/robcecil/1f030e2c8bfa45b567128e50e2156dad

Running Node v11.10.0 on Ubuntu Comic 18.10.

[Michael Lumish]

Can you make sure you don't have any other servers running on that same machine? One possibility here is that another gRPC service without that method implemented is bound to this port and either the bind call is failing (the example code does not check the return value), or they are both binding the port and the incoming connection is going to the wrong one.

To view this discussion on the web visit https://groups.google.com/d/msgid/grpc-io/9bcbda49-2257-4543-abc9-bc5b2600581d%40googlegroups.com.

[Rob Cecil]

That was it. Fork!!

The process was spawned on 3/5.

Thanks!

How can two servers bind to the same ip&port ?

[Michael Lumish]

There is an option on Linux called SO_REUSEPORT, which allows two processes to bind to the same port as long as they set the same options. The gRPC libraries set this option to allow users to get a very basic kind of multiprocessing/load balancing by simply spawning multiple copies of the server process and allowing the kernel to decide which process each connection goes to.

To view this discussion on the web visit https://groups.google.com/d/msgid/grpc-io/4fb6e6e8-79eb-4a44-a289-a0ba73c53fb3%40googlegroups.com.