A MongoDB job queue
Its is a job queue inspired by Resque, but is trying to improve certain shortcomings of Resque's design. In particular, mongo-queue makes it impossible to lose jobs. Jobs are kept in the database until workers have successfully completed them and only then are they removed from the database.
Even if your host or application crashes hard (without chance to catch the exception in the application's runtime), no jobs are lost.
An object that will hold the MongoDB connection and allow manipulation of the job queue.
Options are :
expires: time in milliseconds until a job is no more valid. Defaults to 1h.
timeout: time in milliseconds allowed to workers before a job goes back to the queue to be processed by another worker. Defaults to 10s.
maxAttempts: maximum number of attempts to run the job. Defaults to 5.
host: hostname for the MongoDB database. Defaults to '127.0.0.1'.
port: port for the MongoDB database. Defaults to 27017.
db: either a MongoDB connection or a string for the database name. Defaults to 'queue'.
username: login for an authenticated MongoDB database.
password: password for an authenticated MongoDB database.
enqueue(queue, args..., callback)
Adds a job to the queue.
queue: either a string with the name of the queue, or an object containing :
queue: the name of the queue.
expires: override the
expiresof the connection for this job.
startDate: a Date object defining a future point in time when the job should execute.
args...: any number of arguments your job should take.
callback(err, job): provides the feedback from the database after the job is inserted.
Emitted in case of a connection error.
Emitted when the
Connection object is ready to work.
Base class to create your own job templates, you need to inherit from it.
Function containing your job's code. You can define any arguments you need.
Any synchronous exception thrown will be caught and the job will go back to the queue.
You need to call this function when you are done with the job.
You can provide an error in case anything went wrong.
Worker object that will watch out for new jobs and run them.
constructor(connection, templates, options)
Options are :
timeout: time in milliseconds for the database polling. Defaults to 1s.
rotate: boolean, indicates if you want job types to be processed in a round-robin fashion or sequentially, meaning all jobs of type A would have to done before jobs of type B. Defaults to false.
workers: integer indicating the maximum number of jobs to execute in parallel. Defaults to 3.
Starts the polling of the database.
Stops the worker, it will not interrupt an ongoing job.
Emitted on polling errors, unknown template definitions or job error.
Emitted when the queue has no more job to process or if there is no job to run on a poll.
Emitted after a call to
stop() and once all the jobs are stopped.
queue = require 'mongo-queue' # First declare your job by extending queue.Template class Addition extends queue.Template perform: (a, b) -> console.log a + ' + ' + b + ' = ' + (a + b) @complete() # Create a connection to the database options = host: 'localhost', port: 27017, db: 'test' connection = new queue.Connection options # Listen to connection errors connection.on 'error', console.error # Put some jobs into the queue connection.enqueue Addition.name, 1, 1, (err, job) -> if err then console.log(err) else console.log('Job added :', job) connection.enqueue Addition.name, 2, 4, (err, job) -> if err then console.log(err) else console.log('Job added :', job) connection.enqueue Addition.name, 3, 6, (err, job) -> if err then console.log(err) else console.log('Job added :', job) connection.enqueue Addition.name, 4, 8, (err, job) -> if err then console.log(err) else console.log('Job added :', job) # Now you need a worker who will process the jobs worker = new queue.Worker connection, [ Addition ] worker.on 'error', console.error worker.poll()