Bluebird async test

bluebird.coffee

global.P = require 'bluebird'

backoff = 100
max_attempts = 10
_random_time = -> Math.random() * 3000 + 1000;
_backoff = (attempt) -> if attempt > 0 then backoff * Math.pow(2, attempt-1) else 0
_with_retry = (err, attempt, res, rej, callback) ->
  return rej(err) if attempt >= max_attempts
  P.try ->
    return unless err?
    console.info err
    grants = [do_stuff('grant1', 1), do_stuff('grant2', 1)]
    P.settle(grants)
  .delay _backoff(attempt)
  .then ->
    callback res, (err) ->
      console.info "Retry attempt: #{attempt + 1}"
      _with_retry err, ++attempt, res, rej, callback

do_stuff = (name, chance) ->
  new P (res, rej) ->
    _with_retry null, 0, res, rej, (resolve, reject) ->
      get_result = ->
        roll = Math.random()
        if roll < chance
          resolve task: name, status: 'ok', roll: roll
        else
          reject task: name, status: 'error', roll: roll
      delay = _random_time()
      console.info "Trying: #{name}... [#{delay}]"
      timer = setTimeout get_result, delay
      #timer.unref()

P.try ->
  do_stuff('task1', 0.2)
  .then (res) -> console.info res
  return 'hello'
.then (res) ->
  console.info res
  do_stuff('other_task', 1)
.then (res) ->
  console.info res