Retries with exponential backoff using Bluebird

retry-promise.coffee

_ = require 'lodash'
Promise = require 'bluebird'

Promise.retry = (action, options = {}) ->
  _.merge
    max: 5
    backoff: 500
  , options

  d = Promise.defer()

  do_action = (attempt, err) ->
    if attempt > options.max
      return d.reject err

    Promise.delay options.backoff * attempt
    .then action
    .then (data) ->
      return d.resolve data
    , (err) ->
      return do_action attempt++, err

  process.nextTick ->
    do_action 0

  return d.promise
  

# Example Usage

Request = Promise.promisifyAll (require 'request')

retry_options =
  max: 3
  backoff: 1000

Promise.retry ->
  Request.getAsync 'http://example.com'
, retry_options
.spread (res, data) ->
  # carry on