Error: 14 UNAVAILABLE: read ECONNRESET in gRPC Client connection

Question

Below is a very minimal gRPC Server in NodeJS.

greeter_server.js

var PROTO_PATH = __dirname + '/../../protos/helloworld.proto';
var grpc = require('@grpc/grpc-js');
var protoLoader = require('@grpc/proto-loader');
var packageDefinition = protoLoader.loadSync(
    PROTO_PATH,
    {keepCase: true,
     longs: String,
     enums: String,
     defaults: true,
     oneofs: true
    });
var hello_proto = grpc.loadPackageDefinition(packageDefinition).helloworld;

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

function main() {
  var server = new grpc.Server();
  server.addService(hello_proto.Greeter.service, {sayHello: sayHello});
  server.bindAsync('0.0.0.0:50051', grpc.ServerCredentials.createInsecure(), () => {
    server.start();
  });
}

main();

I was able to host the above server in Cloud Run and I was given a url to access the server which is of the form https://greeter-service-abcdefghij-ue.a.run.app.

Below is a client to connect to the server above.

greeter_client.js

var PROTO_PATH = __dirname + '/../../protos/helloworld.proto';

var parseArgs = require('minimist');
var grpc = require('@grpc/grpc-js');
var protoLoader = require('@grpc/proto-loader');
var packageDefinition = protoLoader.loadSync(
    PROTO_PATH,
    {keepCase: true,
     longs: String,
     enums: String,
     defaults: true,
     oneofs: true
    });
var hello_proto = grpc.loadPackageDefinition(packageDefinition).helloworld;

function main() {

  var target = 'localhost:50051'; //If I change this to greeter-service-abcdefghij-ue.a.run.app I get an error
  var client = new hello_proto.Greeter(target,
                                       grpc.credentials.createInsecure());
  var user='world';
  client.sayHello({name: user}, function(err, response) {
    console.log('Greeting:', response.message);
  });
}

main();

Everything works perfectly if I am running both the server and client on localhost but the moment I change the clients connection address from localhost:50051 to greeter-service-abcdefghij-ue.a.run.app I get the following error:

Error: 14 UNAVAILABLE: read ECONNRESET

Is there a specific way to connect to the server when it has been hosted?

Thank you

Answer 1

One possible problem is that you are not binding the server to the right port. The Cloud Run documentation says

The only special requirement for a gRPC server running in Cloud Run is to listen at the port specified by the PORT environment variable