loic-go/pkg/loic/loic.go

package loic

import (
	"context"
	"log"
	"net/http"
	"sync"
	"time"

	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/metric"
)

var meter = otel.Meter("loic")
var requestsSent metric.Int64Counter
var currentTest *Test
var isRunning bool
var TestDone = make(chan struct{})

func init() {
	var err error
	requestsSent, err = meter.Int64Counter("requests_sent",
		metric.WithDescription("Number of requests sent"),
		metric.WithUnit("1"),
	)
	if err != nil {
		log.Fatalf("failed to create counter: %v", err)
	}
	isRunning = false
	log.Println("LOIC initialized")
}

type Test struct {
	TargetURL   string
	Concurrency int
	Duration    time.Duration
	RampUpTime  time.Duration
	ctx         context.Context
	cancel      context.CancelFunc
	wg          sync.WaitGroup
}

func StartTest(targetURL string, concurrency int, duration time.Duration, rampUp time.Duration) {
	if isRunning {
		log.Println("Test already running, skipping start")
		return
	}
	log.Printf("Starting test with target: %s, concurrency: %d, duration: %v, rampUp: %v", targetURL, concurrency, duration, rampUp)
	ctx, cancel := context.WithCancel(context.Background())
	currentTest := &Test{
		TargetURL:   targetURL,
		Concurrency: concurrency,
		Duration:    duration,
		RampUpTime:  rampUp,
		ctx:         ctx,
		cancel:      cancel,
	}
	isRunning = true
	log.Println("isRunning set to true, launching goroutine")
	go func() {
		currentTest.run()
		close(TestDone)
	}()
}

func StopTest() {
	if currentTest != nil && isRunning {
		log.Println("Stopping test")
		currentTest.cancel()
		currentTest.wg.Wait()
		currentTest = nil
		isRunning = false
		log.Println("Test stopped, isRunning set to false")
	} else {
		log.Println("No test running to stop")
	}
}

func IsTestRunning() bool {
	return isRunning
}

func (t *Test) run() {
	defer func() {
		isRunning = false
		log.Println("Test run completed, isRunning set to false")
	}()
	log.Println("Starting test run")

	// Start first worker immediately
	if t.Concurrency > 0 {
		log.Println("Starting worker 1")
		t.startWorker()
		currentConcurrency := 1
		if t.Concurrency > 1 {
			for i := 1; i < t.Concurrency; i++ {
				select {
				case <-time.After(t.RampUpTime / time.Duration(t.Concurrency-1)):
					currentConcurrency++
					log.Printf("Starting worker %d", currentConcurrency)
					t.startWorker()
				case <-t.ctx.Done():
					log.Println("Context cancelled during ramp-up, exiting run")
					return
				}
			}
		}
	}

	// Wait for the duration or context cancellation
	select {
	case <-time.After(t.Duration):
		log.Println("Duration reached, cancelling test")
		t.cancel()
	case <-t.ctx.Done():
		log.Println("Context cancelled, exiting run")
	}
	log.Println("Waiting for all workers to finish")
	t.wg.Wait()
}

func (t *Test) startWorker() {
	t.wg.Add(1)
	go func() {
		defer t.wg.Done()
		log.Println("Worker started")
		for {
			select {
			case <-t.ctx.Done():
				log.Println("Worker stopped due to context cancellation")
				return
			default:
				resp, err := http.Get(t.TargetURL)
				if err != nil {
					log.Println("Error in worker: %v", err)
				} else {
					resp.Body.Close()
					requestsSent.Add(t.ctx, 1)
					log.Println("Request sent, counter incremented")
				}
				time.Sleep(time.Second / time.Duration(t.Concurrency))
			}
		}
	}()
}