prisme-flow/nodes/bridge/daemon/daemon.js

prisme platform flow engine

/**
 * Created by prisme.io on 09/06/2017.
 */

module.exports = function (RED) {
  'use strict'
  var spawn = require('child_process').spawn

  function DaemonNode (n) {
    RED.nodes.createNode(this, n)
    this.cmd = n.command
    this.args = n.args.trim().split(' ') || []
    this.cr = n.cr
    this.op = n.op
    this.redo = n.redo
    this.running = false
    var node = this

    function inputlistener (msg) {
      if (msg != null) {
        if (msg.hasOwnProperty('kill') && node.running) {
          if (typeof msg.kill !== 'string' || msg.kill.length === 0 || !msg.kill.toUpperCase().startsWith('SIG')) { msg.kill = 'SIGINT' }
          node.child.kill(msg.kill.toUpperCase())
        } else if (msg.hasOwnProperty('start') && !node.running) {
          runit()
        } else {
          if (!Buffer.isBuffer(msg.payload)) {
            if (typeof msg.payload === 'object') { msg.payload = JSON.stringify(msg.payload) }
            if (typeof msg.payload !== 'string') { msg.payload = msg.payload.toString() }
            if (node.cr === true) { msg.payload += '\n' }
          }
          if (RED.settings.verbose) { node.log('inp: ' + msg.payload) }
          if (node.child !== null && node.running) { node.child.stdin.write(msg.payload) } else { node.warn('Command not running') }
        }
      }
    }

    function runit () {
      node.child = spawn(node.cmd, node.args)
      if (RED.settings.verbose) { node.log(node.cmd + ' ' + JSON.stringify(node.args)) }
      node.status({fill: 'green', shape: 'dot', text: 'running'})
      node.running = true
      var line = ''

      node.on('input', inputlistener)

      node.child.stdout.on('data', function (data) {
        if (node.op === 'string') { data = data.toString() }
        if (node.op === 'number') { data = Number(data) }
        if (RED.settings.verbose) { node.log('out: ' + data) }
        if (node.op === 'lines') {
          line += data.toString()
          var bits = line.split('\n')
          while (bits.length > 1) {
            node.send([{payload: bits.shift()}, null, null])
          }
          line = bits[0]
        } else {
          if (data && (data.length !== 0)) {
            node.send([{payload: data}, null, null])
          }
        }
      })

      node.child.stderr.on('data', function (data) {
        if (node.op === 'string') { data = data.toString() }
        if (node.op === 'number') { data = Number(data) }
        if (RED.settings.verbose) { node.log('err: ' + data) }
        node.send([null, {payload: data}, null])
      })

      node.child.on('close', function (code, signal) {
        if (RED.settings.verbose) { node.log('ret: ' + code + ':' + signal) }
        node.running = false
        node.child = null
        var rc = code
        if (code === null) { rc = signal }
        node.send([null, null, {payload: rc}])
        node.status({fill: 'red', shape: 'ring', text: 'stopped'})
      })

      node.child.on('error', function (err) {
        if (err.errno === 'ENOENT') { node.warn('Command not found') } else if (err.errno === 'EACCES') { node.warn('Command not executable') } else { node.log('error: ' + err) }
        node.status({fill: 'grey', shape: 'dot', text: 'error'})
      })
    }

    if (node.redo === true) {
      var loop = setInterval(function () {
        if (!node.running) {
          node.removeListener('input', inputlistener)
          node.warn('Restarting : ' + node.cmd)
          runit()
        }
      }, 10000)  // Restart after 10 secs if required
    }

    node.on('close', function (done) {
      clearInterval(loop)
      if (node.child != null) { node.child.kill('SIGKILL') }
      if (RED.settings.verbose) { node.log(node.cmd + ' stopped') }
      node.status({})
      setTimeout(function () { done() }, 100)
    })

    runit()
  }
  RED.nodes.registerType('daemon', DaemonNode)
}