Simple script to test Google Cloud Functions background functions

testbg.js

#!/usr/bin/env node
const join = require('path').join;
const read = require('fs').readFileSync;

const args = process.argv.slice(2);
const fnName = args[0];
const payload = args[1];

const fileBuffer = read(join(__dirname, 'payloads', `${payload}.json`));

// construct event to be sent
const event = {
  data: {
    data: fileBuffer.toString('base64'),
  },
  timestamp: (new Date()).toISOString(),
  eventId: 1,
};

const fn = require(join(process.cwd(), 'build', fnName)).default;

const originalLog = console.log;

// alias so we can see what's happening
console.log = (...args) => originalLog.apply(console, [`[${fnName}]`, ...args]);
const thenFn = () => { console.log = originalLog; console.log('Test Complete!')}
// let it do what it needs to do
if (fn.length === 1) {
  const res = fn(event);
  if (res instanceof Promise) {
    res.then(thenFn);
  } else {
    throw new Error('Function only has one param and doesn\'t return a Promise');
  }
} else {
  const x = setTimeout(() => {
    throw new Error('Function has taken too long to execute');
    process.exit(1);
  }, 8000); // die after 8 seconds
  const cb = c => () => {clearTimeout(x); c()}
  new Promise(res => fn(event, cb(res))).then(thenFn); // will keep running until cb is called
}