worker

Package worker is a Go package designed to facilitate the easy parallelization of a number of tasks N with up to n at a time being computed concurrently.

Getting started

$ go get github.com/jimmysawczuk/worker

Using in your program

Design

To use this package, all you need to do is package your tasks into types that satisfy the following interface:

type Job interface {
	Run()
}

Implementation

From there, it's easy to add your task to the queue and start it:

type SampleJob struct {
	Name     string
	Duration time.Duration
}

func (s *SampleJob) Run() {

	time.Sleep(s.Duration)
	log.Printf("Done, slept for %s\n", s.Duration)

}

// only do 3 jobs at a time
worker.MaxJobs = 3

w := worker.NewWorker()
w.Add(SampleJob{
	Name: "sleep 1",
	Duration: 1 * time.Second,
})

w.Add(SampleJob{
	Name: "sleep 2",
	Duration: 2 * time.Second,
})

// ... and so forth

w.RunUntilDone()

Your Jobs are packaged internally as Packages, which have nice features such as storing a unique-per-worker ID, as well as the return value that is retrieved from the channel. This is mostly used for event handling though; keep in mind that you can store your information in this value or you can simply use your custom Job type and store more custom information.

Events

You can also listen for events from the Worker and react appropriately. Currently, three events are fired: JobQueued, JobStarted, and JobFinished. Add an event handler like so:

w.On(worker.JobStarted, func(pk *worker.Package, args ...interface{}) {
	// You can use type assertion to get back your original job from this:
	job := pk.Job()
})

Currently each event emitter only passes one argument, the relevant Package that emitted the event. There may be more added later, for other events, but the Package will always be the first argument.

More documentation

You can find more documentation at GoDoc.

Examples

• less-tree, a recursive, per-directory LESS compiler uses worker