fix found data races

attacker/attacker.go

@@ -5,6 +5,7 @@ import (
 	"math"
 	"net"
 	"net/http"
+	"sync"
 	"time"
 
 	vegeta "github.com/tsenart/vegeta/v12/lib"
@@ -110,29 +111,38 @@ func Attack(ctx context.Context, target string, resCh chan *Result, metricsCh ch
 
 	child, cancelChild := context.WithCancel(ctx)
 	defer cancelChild()
-	go sendMetrics(child, metrics, metricsCh)
+
+	// used to protect metrics
+	mu := &sync.Mutex{}
+	go sendMetrics(child, metrics, metricsCh, mu)
 
 	for res := range opts.Attacker.Attack(targeter, rate, opts.Duration, "main") {
 		select {
 		case <-ctx.Done():
 			opts.Attacker.Stop()
 			return
 		default:
+			mu.Lock()
 			metrics.Add(res)
+			p50 := metrics.Latencies.Quantile(0.50)
+			p90 := metrics.Latencies.Quantile(0.90)
+			p95 := metrics.Latencies.Quantile(0.95)
+			p99 := metrics.Latencies.Quantile(0.99)
+			mu.Unlock()
 			resCh <- &Result{
 				Latency: res.Latency,
-				P50:     metrics.Latencies.Quantile(0.50),
-				P90:     metrics.Latencies.Quantile(0.90),
-				P95:     metrics.Latencies.Quantile(0.95),
-				P99:     metrics.Latencies.Quantile(0.99),
+				P50:     p50,
+				P90:     p90,
+				P95:     p95,
+				P99:     p99,
 			}
 		}
 	}
 	metrics.Close()
-	metricsCh <- newMetrics(metrics)
+	metricsCh <- newMetrics(metrics, mu)
 }
 
-func sendMetrics(ctx context.Context, metrics *vegeta.Metrics, ch chan<- *Metrics) {
+func sendMetrics(ctx context.Context, metrics *vegeta.Metrics, ch chan<- *Metrics, mu *sync.Mutex) {
 	// TODO: Make the interval changeable.
 	ticker := time.NewTicker(250 * time.Millisecond)
 	defer ticker.Stop()
@@ -142,7 +152,7 @@ func sendMetrics(ctx context.Context, metrics *vegeta.Metrics, ch chan<- *Metric
 		case <-ctx.Done():
 			return
 		case <-ticker.C:
-			ch <- newMetrics(metrics)
+			ch <- newMetrics(metrics, mu)
 		}
 	}
 }

attacker/metrics.go

@@ -1,6 +1,7 @@
 package attacker
 
 import (
+	"sync"
 	"time"
 
 	vegeta "github.com/tsenart/vegeta/v12/lib"
@@ -68,7 +69,9 @@ type ByteMetrics struct {
 	Mean float64 `json:"mean"`
 }
 
-func newMetrics(m *vegeta.Metrics) *Metrics {
+func newMetrics(m *vegeta.Metrics, mu *sync.Mutex) *Metrics {
+	mu.Lock()
+	defer mu.Unlock()
 	return &Metrics{
 		Latencies: LatencyMetrics{
 			Total: m.Latencies.Total,

gui/drawer.go

@@ -3,6 +3,7 @@ package gui
 import (
 	"context"
 	"fmt"
+	"sync/atomic"
 	"time"
 
 	"github.com/mum4k/termdash/cell"
@@ -20,7 +21,7 @@ type drawer struct {
 	metricsCh chan *attacker.Metrics
 
 	// aims to avoid to perform multiple `redrawChart`.
-	chartDrawing bool
+	chartDrawing int32
 }
 
 // redrawChart appends entities as soon as a result arrives.
@@ -38,7 +39,7 @@ func (d *drawer) redrawChart(ctx context.Context, maxSize int) {
 		return append(to, float64(val)/float64(time.Millisecond))
 	}
 
-	d.chartDrawing = true
+	atomic.StoreInt32(&d.chartDrawing, 1)
 L:
 	for {
 		select {
@@ -83,7 +84,7 @@ L:
 			)
 		}
 	}
-	d.chartDrawing = false
+	atomic.StoreInt32(&d.chartDrawing, 0)
 }
 
 func (d *drawer) redrawGauge(ctx context.Context, maxSize int) {

gui/keybinds.go

@@ -2,6 +2,7 @@ package gui
 
 import (
 	"context"
+	"sync/atomic"
 	"time"
 
 	"github.com/mum4k/termdash/container"
@@ -47,7 +48,7 @@ func keybinds(ctx context.Context, cancel context.CancelFunc, c *container.Conta
 }
 
 func attack(ctx context.Context, d *drawer, target string, opts attacker.Options) {
-	if d.chartDrawing {
+	if atomic.LoadInt32(&d.chartDrawing) == 1 {
 		return
 	}
 	requestNum := opts.Rate * int(opts.Duration/time.Second)

gui/keybinds_test.go

@@ -187,11 +187,11 @@ func TestAttack(t *testing.T) {
 
 	tests := []struct {
 		name         string
-		chartDrawing bool
+		chartDrawing int32
 	}{
 		{
 			name:         "chart is drawing",
-			chartDrawing: true,
+			chartDrawing: 1,
 		},
 	}
 	for _, tt := range tests {