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kyoo: A Go library providing an unlimited job queue and concurrent worker pools

About

kyoo is the phonetic transcription of the word queue. It provides a job queue that can hold as much jobs as resources are available on the running system.

The queue has the following characteristics:

• No limit of jobs to be queued (only limited by system resources = memory)
• Concurrent processing of jobs using worker pools
• When stopping queue, pending jobs are still processed

The library contains a simple Job interface and a simple FuncExecutorJob that just executes a given function and implements that interface. With that nearly all kinds of workloads should be processable already but of course it is possible to add custom implementations of the Job interface.

Possible use cases for the library are:

• Consumers for message queues like RabbitMQ or Amazon SQS
• Processing web server requests offloading time extensive work into background jobs
• All kinds of backend processing jobs like image optimization, etc.

Example

The following example shows a simple http server offloading jobs to the jobqueue that is constantly processed in the background.

package main

import (
	"fmt"
	"log"
	"net/http"
	"runtime"
	"time"

	jobqueue "github.com/dirkaholic/kyoo"
	"github.com/dirkaholic/kyoo/job"
)

var queue *jobqueue.JobQueue

func handler(w http.ResponseWriter, r *http.Request) {
	queue.Submit(&job.FuncExecutorJob{Func: func() error {
		return doTheHeavyBackgroundWork(r.URL.Path)
	}})
	fmt.Printf("%s - submitted %s !!\n", time.Now().String(), r.URL.Path)

	fmt.Fprint(w, "Job added to queue.")
}

func main() {
	queue = jobqueue.NewJobQueue(runtime.NumCPU() * 2)
	queue.Start()

	http.HandleFunc("/", handler)
	log.Fatal(http.ListenAndServe(":8080", nil))
}

func doTheHeavyBackgroundWork(path string) error {
	time.Sleep(2 * time.Second)
	fmt.Printf("%s - processed %s !!\n", time.Now().String(), path)
	return nil
}

Test the offloading by sending a bunch of http requests to the server

$ for i in {1..10}; do http http://127.0.0.1:8080/test/$i; done

The output on http server side should be similar like this

2020-01-09 21:36:36.156277 +0100 CET m=+5.733617272 - submitted /test/1 !!
2020-01-09 21:36:36.443521 +0100 CET m=+6.020861136 - submitted /test/2 !!
2020-01-09 21:36:36.730535 +0100 CET m=+6.307874793 - submitted /test/3 !!
2020-01-09 21:36:37.021405 +0100 CET m=+6.598744533 - submitted /test/4 !!
2020-01-09 21:36:37.311973 +0100 CET m=+6.889312431 - submitted /test/5 !!
2020-01-09 21:36:37.609868 +0100 CET m=+7.187208115 - submitted /test/6 !!
2020-01-09 21:36:37.895222 +0100 CET m=+7.472561850 - submitted /test/7 !!
2020-01-09 21:36:38.160524 +0100 CET m=+7.737863891 - processed /test/1 !!
2020-01-09 21:36:38.171491 +0100 CET m=+7.748830724 - submitted /test/8 !!
2020-01-09 21:36:38.445832 +0100 CET m=+8.023171514 - processed /test/2 !!
2020-01-09 21:36:38.448423 +0100 CET m=+8.025762679 - submitted /test/9 !!
2020-01-09 21:36:38.730541 +0100 CET m=+8.307880933 - submitted /test/10 !!
2020-01-09 21:36:38.735158 +0100 CET m=+8.312497505 - processed /test/3 !!
2020-01-09 21:36:39.024788 +0100 CET m=+8.602128093 - processed /test/4 !!
2020-01-09 21:36:39.315991 +0100 CET m=+8.893331115 - processed /test/5 !!
2020-01-09 21:36:39.614848 +0100 CET m=+9.192187633 - processed /test/6 !!
2020-01-09 21:36:39.896692 +0100 CET m=+9.474031970 - processed /test/7 !!
2020-01-09 21:36:40.175952 +0100 CET m=+9.753291345 - processed /test/8 !!
2020-01-09 21:36:40.451877 +0100 CET m=+10.029216847 - processed /test/9 !!
2020-01-09 21:36:40.734289 +0100 CET m=+10.311628415 - processed /test/10 !!

More examples

• SQS worker