atomic-queue

atomic-queue

a crash friendly queue that persists queue state and can restart. uses a worker pool and has configurable concurrency

API

for example usage see test.js

var queue = require('atomic-queue')(worker, opts)

initialize a new queue with a worker function and optional options. queue is a stream

you queue things by writing them to the queue stream:

queue.write('hello')
queue.write('goodbye')
queue.write({name: 'bob'})

worker must be a function that has this API:

function work (data, done) {
  // do work, then call done with (err) if there was an error
}

data in the worker function will be the data you wrote into the queue above

events

in addition to standard stream events you can also listen to the following:

queue.on('ready')

emitted after startup when the queue state has been read from disk and the queue is now ready to start working

queue.on('error')

when a catastrophic error has occurred. you must handle this. receiving this also means the queue stream has been destroyed.

queue.on('idle')

when the number of pending jobs reaches 0. may be called multiple times

queue.on('finish')

when the writable side of the queue has been ended and all jobs have finished processing

queue.on('update-start')

when the queue starts flushing its state to disk

queue.on('update-end')

when the queue finishes flushing its state to disk

queue.pool.on('start')

when a job starts working

queue.pool.on('finish')

when a job finishes working