generator-swiftserver/refresh/templates/common/apic-node-wrapper.js

Generator for Kitura REST webservice servers

/*
 * Copyright IBM Corporation 2016
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var EventEmitter = require('events')
var fs = require('fs')
var path = require('path')
var util = require('util')
var net = require('net')
var debug = require('debug')('generator-swiftserver:refresh:apic-node-wrapper')

module.exports = new EventEmitter()
function getRandomUnusedPort (tries, avoidPort, cb) {
  if (tries <= 0) { cb(null); return }

  var dummyServer = net.createServer()
  dummyServer.listen(0, () => {
    var port = dummyServer.address().port
    dummyServer.close()
    if (port === avoidPort) {
      getRandomUnusedPort(tries - 1, avoidPort, cb)
      return
    }
    cb(port)
  })
  dummyServer.on('error', (err) => {
    debug(`Error when trying to use default port: ${err}`)
    getRandomUnusedPort(tries - 1, avoidPort, cb)
  })
}
function exitChild (code) {
  if (swiftServerProcess) {
    swiftServerProcess.kill('SIGINT')
    console.error('kill child')
  }
  console.error('exit ' + code)
}
function handleSignal () {
  exitChild()
  process.exit(1)
}
process.on('SIGTERM', handleSignal)
process.on('SIGINT', handleSignal)
process.on('exit', exitChild)

var swiftServerProcess = null
var projectDir = __dirname
var sourcesDir = path.join(projectDir, 'Sources')
var mainModules = fs.readdirSync(sourcesDir)
                    .filter((file) => fs.readdirSync(path.join(sourcesDir, file)).indexOf('main.swift') !== -1)
if (mainModules.length === 0) {
  console.error('Failed to find main module for project')
  process.exit(2)
} else if (mainModules.length > 1) {
  console.error('Found multiple candidates for main module in project: ' + util.inspect(mainModules))
  process.exit(2)
} else {
  // Exactly 1 main module found
  var mainModule = mainModules[0]
  var wrapperPort = process.env['PORT']
  if (!wrapperPort) {
    console.error('Process manager did not provide a port')
    process.exit(3)
  }
  var wrapperServer = net.createServer()
  // NOTE: We call listen here rather than after the swift server
  // starts since the first listen is communicated back through the
  // cluster to the launcher. We don't want to call getRandomUnusedPort()
  // before here, since it uses listen() calls to check if a port is
  // unused.
  wrapperServer.listen(wrapperPort)
  wrapperServer.on('error', (err) => {
    console.error('Failed to start wrapper server: ' + err.stack)
    process.exit(5)
  })
  getRandomUnusedPort(10, wrapperPort, (swiftServerPort) => {
    if (!swiftServerPort) {
      console.error('Failed to find unused port for swift server')
      process.exit(4)
    }

    console.error('Starting Swift server')
    var appCommand = path.join(projectDir, '.build', 'debug', mainModule)
    process.env['PORT'] = swiftServerPort
    var options = { cwd: projectDir, detached: false, stdio: 'inherit' }
    swiftServerProcess = require('child_process').spawn(appCommand, [], options)
    swiftServerProcess.on('error', (err) => {
      console.error('Failed to start Swift server: ' + err.stack)
      process.exit(6)
    })
    swiftServerProcess.on('exit', (code, signal) => {
      console.error('Swift Server exited (code: ' + code + ', signal: ' + signal + ')')
      process.exit(7)
    })
    wrapperServer.on('connection', (socket) => {
      var serverConnection = net.createConnection(swiftServerPort)
      socket.pipe(serverConnection)
      serverConnection.pipe(socket)
    })
    module.exports.emit('started')
  })
}