example.go

package main

const MaxLength = 1 << 20

var (
	addr     = flag.String("listen", ":8000", "listen for requests")
	numprocs = flag.Int("p", runtime.NumCPU(), "number of workers to start")
	maxqueue = flag.Int("q", runtime.NumCPU()*2, "largest queue size")

	jobs   chan Job
)

func main() {
	flag.Parse()

	jobs = make(chan Job, *maxqueue)
	for i := 0; i < *numprocs; i++ {
		go Work(jobs)
	}

	http.ListenAndHandle(*addr, request)
}

type Job func() error

func Work(jobs chan Job) {
	for job := range jobs {
		if err := job(); err != nil {
			log.Errorf("Error handling job: %s", err.Error())
		}
	}
}

func request(w http.ResponseWriter, r *http.Request) {
	if r.Method != "POST" {
		w.WriteHeader(http.StatusMethodNotAllowed)
		return
	}

	var content = &PayloadCollection{}
	err := json.NewDecoder(io.LimitReader(r.Body, MaxLength)).Decode(&content)
	if err != nil {
		w.Header().Set("Content-Type", "application/json; charset=UTF-8")
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	for _, payload := range content.Payloads {
		jobs <- payload.UploadToS3
	}

	w.WriteHeader(http.StatusOK)
}