const http = require('http')
const service = require('../my/service);
const server = http.createServer(service)
server.listen(process.env.PORT || 0) // <-- Random port by default!

const grpc = require('grpc')
const services = require('./service_grpc_pb')
const server = new grpc.Server()
server.addService(services.MyService, { ... })
server.bind('0.0.0.0:0', grpc.ServerCredentials.createInsecure())
server.start()