node-tracing.js

    // make grpc call to grpc server - localhost on port 50051
    var client = new hello_proto.Greeter('localhost:50051', grpc.credentials.createInsecure());
    var user;
    if (process.argv.length >= 3) {
        user = process.argv[2];
        console.log("user is " + user);
    } else {
        user = 'world';
    }