iocast

A zero-dependency async task running library that aims to be simple, easy to use and flexible.

installation

go get github.com/svaloumas/iocast

usage

The module utilizes Go Generics internally, enabling the flexibility to define your custom structs to use as arguments and arbitrary result types in your tasks.

func DownloadContent(ctx context.Context, args *Args) (string, error) {

	contentChan := make(chan []byte)
	go func() {
		contentChan <- fetchContent(args.addr, args.id)
		close(contentChan)
	}()
	select {
	case content := <-contentChan:
		return saveToDisk(content)
	case <-ctx.Done():
		return "", ctx.Err()
	}
}

func main() {
	numOfWorkers := runtime.NumCPU()
	p := iocast.NewWorkerPool(numOfWorkers, numOfWorkers*2)
	p.Start(context.Background())
	defer p.Stop()

	args := &Args{addr: "http://somewhere.net", id: 1}
	taskFn := iocast.NewTaskFunc(context.Background(), args, DownloadContent)

	t := iocast.TaskBuilder(taskFn).
		MaxRetries(2).
		BackOff([]time.Duration{2*time.Second, 5*time.Second}).
		Build()

	p.Enqueue(t)

	m := t.Metadata()
	log.Printf("status: %s", m.Status)

	result := <-t.Wait()
}

See examples for a detailed illustration of how to run simple tasks and linked tasks as pipelines.

features

• Generic Task Arguments. Pass any built-in or custom type as an argument to your tasks.
• Flexible Task Results. Return any type of value from your tasks.
• Context Awareness. Optionally include a context when running tasks.
• Retry attemtps. Define the number of retry attempts for each task.
• Task Pipelines. Chain tasks to execute sequentially, with the option to pass the result of one task as the argument for the next.
• Database Interface. Use the built-in in-memory database or use custom drivers for other storage engines by implementing an one-func interface.
• Task Metadata. Retrieve metadata such as status, creation time, execution time, and elapsed time. Metadata is also stored with the task results.
• Scheduler: Schedule tasks to run at a specific timestamp.
• Retries backoff mechanism: Set the duration of the intervals between failed retry attempts.
• Scheduler: Add support for periodic tasks.

test

go test -v ./...