server from https://github.com/ChristianOConnor/spheron-react-api-stack

server.js

var express = require("express");
var app = express();
require("dotenv").config();
const GoogleAuth = require("google-auth-library").GoogleAuth;
const cors = require("cors");

app.use(
  cors({ origin: process.env.ORIGIN, credentials: process.env.CREDENTIALS })
);

app.get("/hello", async function (req, res) {
  const keyInJsn = JSON.parse(process.env.CREDENTIALS_STR);
  const auth = new GoogleAuth({
    credentials: keyInJsn,
  });
  const url = process.env.RUN_APP_URL;

  //Create your client with an Identity token.
  const client = await auth.getIdTokenClient(url);
  const result = await client.request({ url });
  const resData = result.data;
  res.send(resData);
});

var server = app.listen(8081, function () {
  var host = server.address().address;
  var port = server.address().port;
  console.log("Example app listening at http://localhost:", port);
});