index.js

'use strict'
const dns = require('dns')
const setConfig = require('./src/config.js')
const Context = require('./src/context.js')
const Callback = require('./src/callback.js')
const Report = require('./src/report.js')
const globals = require('./src/globals')

function makeDnsPromise(host) {
  return new Promise((resolve, reject) => {
    dns.lookup(host, (err, address) => {
      if (err) {
        reject(err)
      }
      resolve(address)
    })
  })
}

function setupTimeoutCapture(config, report, context) {
  if (config.timeoutWindow < 1) {
    return
  }

  var endTime = 599900  /* Maximum execution: 100ms short of 5 minutes */
  if (config.timeoutWindow > 0 && context && context.getRemainingTimeInMillis) {
    endTime = Math.max(0, context.getRemainingTimeInMillis() - config.timeoutWindow)
  }

  return setTimeout(() => {
    report.send(new Error("Timeout Exceeded."), function noop() {})
  }, endTime)
}

module.exports = function(options) {
  var fn = function(func) {
    fn.metricsQueue = []
    const config = setConfig(options)

    if (!config.clientId) {
      // No-op if user doesn't set an IOpipe token.
      return func
    }

    /* resolve DNS early on coldstarts */
    var dnsPromise = makeDnsPromise(config.host)

    return function() {
      fn.metricsQueue = []
      var args = [].slice.call(arguments)

      if (!globals.COLDSTART) {
        /* Get an updated DNS record. */
        dnsPromise = makeDnsPromise(config.host)
      }

      var startTime = process.hrtime()
      const report = new Report(config, args[1], startTime, fn.metricsQueue, dnsPromise)

      var timeout = setupTimeoutCapture(config, report, args[1])

      var callback = (err, cb) => {
        if (timeout) { clearTimeout(timeout) }
        report.send(err, cb)
      }

      /* Mangle arguments, wrapping callbacks. */
      args[1] = Context(callback, args[1])
      args[2] = Callback(callback, args[2])

      try {
        return func.apply(this, args)
      }
      catch (err) {
        clearTimeout(timeout)
        report.send(err, function noop() {})
        return undefined
      }
    }
  }

  // Alias decorate to the wrapper function
  fn.decorate = fn

  fn.log = function(name, value) {
    var numberValue, stringValue
    if (typeof value === 'number') {
      numberValue = value
    } else {
      if(typeof value === 'object') {
        JSON.stringify(value)
      } else {
        stringValue = String(value)
      }
    }
    fn.metricsQueue.push({
      name: name,
      n: numberValue,
      s: stringValue
    })

    fn.VERSION = globals.VERSION
  }

  return fn
}