cypress/cli/lib/exec/spawn.js

const _ = require('lodash')
const cp = require('child_process')
const chalk = require('chalk')
const Promise = require('bluebird')

const downloadUtils = require('../download/utils')
const xvfb = require('./xvfb')

module.exports = {
  start (args, options = {}) {
    args = [].concat(args)

    const needsXvfb = xvfb.isNeeded()

    _.defaults(options, {
      verify: false,
      detached: false,
      stdio: [process.stdin, process.stdout, 'ignore'],
    })

    const spawn = () => {
      return new Promise((resolve) => {
        const child = cp.spawn(downloadUtils.getPathToExecutable(), args, options)
        if (needsXvfb) {
          //// make sure we close down xvfb
          //// when our spawned process exits
          child.on('close', xvfb.stop)
        }

        //// when our spawned process exits
        //// make sure we kill our own process
        //// with its exit code (to bubble up errors)
        child.on('exit', process.exit)

        if (options.detached) {
          child.unref()
        }

        resolve(child)
      })
    }

    if (needsXvfb) {
      return xvfb.start()
      .then(spawn)
      .catch(() => {
        /* eslint-disable no-console */
        console.log('')
        console.log(chalk.bgRed.white(' -Error- '))
        console.log(chalk.red.underline('Could not start Cypress headlessly. Your CI provider must support XVFB.'))
        console.log('')
        process.exit(1)
        /* eslint-enable no-console */
      })
    } else {
      return spawn()
    }
  },
}