uci-socket/src/consumer.js

import { Socket } from 'net'
import path from 'path'
import { promisify } from 'util'
import btc from 'better-try-catch'
import JsonStream from './json-stream'

// import logger from '../../uci-logger/src/logger'
import logger from '@uci-utils/logger'

let log = {}

// TODO change default pipe dir for windows and mac os
const DEFAULT_PIPE_DIR = process.env.SOCKETS_DIR || '/tmp/UCI'
const DEFAULT_SOCKET_NAME = 'uci-sock'

/**
 * Socket Consumer - connects to UCI TCP or Named Pipe Sockets and coummunicates with uci packet.<br/>
 * Extends {@link https://nodejs.org/api/net.html#net_class_net_socket | nodejs net.Socket}
 *  @extends Socket
 */
class SocketConsumer extends Socket {
  /**
   * constructor - Description
   *
   * @param {object} [opts={}] test
   */

  constructor(opts = {}) {
    super()
    log = logger({
      file: 'src/consumer.js',
      class: 'Consumer',
      name: 'socket',
      id: this.id
    })
    this.id = opts.id || opts.name || 'socket:' + new Date().getTime()
    if (!opts.path) {
      if(!opts.host) log.warn({method:'constructor', line:38, opts: opts, msg:'no host supplied using localhost...use named piped instead - opts.path'})
      opts.host = opts.host || '127.0.0.1'
      opts.port = opts.port || 8080
    } else {
      if (typeof opts.path === 'boolean')
        opts.path = path.join(DEFAULT_PIPE_DIR, DEFAULT_SOCKET_NAME)
      if (path.dirname(opts.path) === '.')
        opts.path = path.join(DEFAULT_PIPE_DIR, opts.path)
    }
    this.opts = opts
    // default is keepAlive true, must set to false to explicitly disable
    // if keepAlive is true then consumer will also be reconnecting consumer
    this.keepAlive = 'keepAlive' in opts ? opts.keepAlive : true
    this._ready = false
    this.stream = new JsonStream()
    // bind to class for other class functions
    this.connect = this.connect.bind(this)
    this.close = promisify(this.end).bind(this)
    this.__ready = this.__ready.bind(this)
    this._conAttempt = 0
    this._reconnect = false
    // this._write = this._write.bind(this)
  }

  async connect() {
    return new Promise((resolve, reject) => {

      let initTimeout = {}
      // let endlessAttempts = {}

      if (this.opts.host === '127.0.0.1'|| this.opts.host ==='localhost')
        log.warn({method:'connect', line:107, msg:'tcp consumer on same machine as host, use named Pipe(Unix) Socket Instead'})

      console.log('first connnect attempt for', this.opts.name)

      // this is only for initial drop dead connection failure
      if (this.opts.initTimeout) {
        initTimeout = setTimeout(() => {
          log.fatal({method:'connect', line:69, opts: this.opts, msg:`unable to initially connect to ${this.opts.name} in ${this.opts.initTimeout}s no more attempts!`})
          reject({ opts: this.opts, msg: `unable to connect initially to socket server in ${this.timeout}secs, giving up no more attempts`})
        }
          , this.opts.initTimeout * 1000)
      }

      // connection function  that sets listeners and deals with reconnect
      const _connect = () => {

        this.once('connect', async () => {
          console.log(`${this.opts.name} - has ${this._reconnect ? 're':''}CONNECTED after ${this._conAttempt} attempts`)
          if (!this._reconnect) clearTimeout(initTimeout)
          // clearInterval(endlessAttempts)
          this._listen()
          log.debug({method:'connect', line:113, msg:'connected waiting for socket ready handshake'})
          this.setKeepAlive(this.keepAlive, 3000)
          let [err, res] = await btc(isReady).bind(this)(this.__ready,this.hsInterval,this.hsTimeout)
          if (err) {
            log.error(`${this.opts.name} - could not complete handshake after ${this._reconnect ? 're':''}connect attempt ${this._conAttempt}`)
            if (!this._reconnect) reject(err)
            this.emit('error', new Error('HANDSHAKE'))
          } else {
            log.debug({method:'connect', line:69, msg:'handshake done, authenticating'})
            this.send({cmd:'auth', id:this.opts.clientID, name:this.opts.clientNamem, key:'somebigsecret'})
            // TODO authenticate here by encrypting private key.
            if (!this._reconnect) {
              resolve(res)
              this.emit('connected')
            }
            this.emit('reconnected')  // emit also reconnected for special end user action
            this._ready = true
            this._conAttempts = 0
            this._reconnect = true
          }
        })

        this.on('error', async err => {
          console.log('error emitted', this.opts.name, err.code)
          if (err.code !== 'EISCONN') {
            this._ready = false
            this.emit('ready', false)
            log.debug({ method:'connect', line:130, error: err.code, msg:`connect error ${err.code}, attempting reconnect`})
            this.removeAllListeners()
            this.stream.removeAllListeners()
            this.destroy()
            this._conAttempt += 1
            console.log(`${this.opts.name} - ${this._reconnect ? 're':''}connection attempt ${this._conAttempt}`)
            _connect()
          }  else {
            this._ready = true
            this.emit('ready', true)
            log.error({method:'connect', line:69, msg:'reconnected to socket, ready to go again'})
          }
        })

        if (this.keepAlive) { // only attempt reconnect if keepAlive is set which it is by default
          this.on('end', async () => {
            console.log({method:'connect', line:142, msg:'socket (server) terminated unexpectantly, keepalive set, wait for server to come online'})
            this._ready = false
            this.emit('error', { code: 'DISCONNECTED' })
          })
        }

        // attempt connection
        log.debug({method:'connect', line:149, opts: this.opts, msg:`attempting to connect ${this.id} to socket`})
        super.connect(this.opts)  // ###call nodejs net connect here###

      }  // end connect function

      _connect() // initial connect request to start the ball rolling
    }) //end promise
  }

  async send(ipacket) {
    return new Promise(async resolve => {
      if (!this._ready) resolve({ error: 'socket consumer not connected, aborting send' })
      let packet = Object.assign({}, ipacket)  // need to avoid mutuation for different consumers using same packet instance
      setTimeout(() => {resolve({ error: 'no response from socket in 10sec' })}, 10000)
      packet._header = {
        id: Math.random()
          .toString()
          .slice(2), // need this for when multiple sends for different consumers use same packet instanceack
        sender: { name: this.name, instanceID: this.id },
        path: this.opts.path,
        port: this.opts.port,
        host: this.opts.host
      }
      let [err, res] = await btc(this.stream.serialize)(packet)
      if (err)
        resolve({error: 'unable to serialize packet for sending',packet: packet})
      await this.__write(res)
      this.once(packet._header.id, async function(reply) {
        let res = await this._packetProcess(reply)
        if (!res) { // if packetProcess was not promise
          res = reply
          log.debug({method:'send', line:180, msg:'consumer function was not promise returning further processing may be out of sequence'})
        }
        resolve(res)
      }) //end listener
    })
  }

  // TODO register user alt stream processor (emit 'message' with JSON, serialize function, onData method for raw socket chucks)
  // TODO register authenciation function (set up default)

  registerPacketProcessor(func) {
    this._packetProcess = func
  }

  // PRIVATE METHODS

  async __write(packet) {
    // timeout already set if sockect can't be drained in 10 secs
    return new Promise(resolve => {
      const cb = () => resolve('packet written to consumer side socket stream ')
      if (!super.write(packet)) {
        this.once('drain', cb)
      } else {
        process.nextTick(cb)
      }
    })
  }

  __ready() {
    return this._ready
  }

  async _listen() {
    log.debug('listening for incoming packets from socket')
    // listen for pushed packets
    this.on('pushed', async function(packet) {
      // TODO do some extra security here?
      let res = await this._packetProcess(packet)
      if (!res) {
        // if process was not promise returning then res will be undefined
        log.debug('consumer packet processing function was not promise returning')
      }
    })
    // listen on socket stream
    this.on('data', this.stream.onData)
    this.stream.on('message', messageProcess.bind(this))

    async function messageProcess(packet) {
      log.debug('incoming packet from socket',packet)
      if (packet._handshake) {
        this._ready = true
        return
      }
      // TODO send back ack with consumer ID and authorization and wait
      // when authorized drop through here to emit
      this.emit(packet._header.id, packet)
    }
  }

  // default packet process just a simple console logger.  ignores any cmd: prop
  _packetProcess(packet) {
    console.log('default consumer processor -- log packet from socket to console')
    console.log('replace by calling .registerPacketProcessor(func) with your function')
    console.dir(packet)
  }
} // end class

export default SocketConsumer

// Helper Functions
// wait until a passed ready function returns true
function isReady(ready, wait = 100, timeout = 2000) {
  let time = 0
  return new Promise((resolve, reject) => {
    (function waitReady() {
      if (time > timeout)
        return reject(
          `timeout waiting for socket ready handshake - ${timeout}ms`
        )
      if (ready()) return resolve('ready')
      log.debug({function:'isReady', line:261, msg:`waiting ${wait}ms for handshake`})
      time += wait
      setTimeout(waitReady, wait)
    })()
  })
}