Merge pull request #26 from brenol/fix-panic-when-stopping-infinite-a…

…ttack

fix panic when doing Ctrl-C in the middle of a attack

attacker/attacker.go

@@ -49,9 +49,9 @@ type Result struct {
 // Attack keeps the request running for the specified period of time.
 // Results are sent to the given channel as soon as they arrive.
 // When the attack is over, it gives back final statistics.
-func Attack(ctx context.Context, target string, resCh chan *Result, metricsCh chan *Metrics, opts Options) *Metrics {
+func Attack(ctx context.Context, target string, resCh chan *Result, metricsCh chan *Metrics, opts Options) {
 	if target == "" {
-		return nil
+		return
 	}
 	if opts.Method == "" {
 		opts.Method = DefaultMethod
@@ -88,14 +88,14 @@ func Attack(ctx context.Context, target string, resCh chan *Result, metricsCh ch
 		select {
 		case <-ctx.Done():
 			opts.Attacker.Stop()
+			// metricsCh is already closed (as context is done) so we shouldn't send any metric
+			return
 		default:
 			resCh <- &Result{Latency: res.Latency}
 			metrics.Add(res)
 			metricsCh <- newMetrics(&metrics)
 		}
 	}
 	metrics.Close()
-
-	// TODO: No need to give back metrics anymore.
-	return newMetrics(&metrics)
+	metricsCh <- newMetrics(&metrics)
 }

attacker/attacker_test.go

@@ -74,8 +74,7 @@ func TestAttack(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			resCh := make(chan *Result, 100)
 			metricsCh := make(chan *Metrics, 100)
-			got := Attack(ctx, tt.target, resCh, metricsCh, tt.opts)
-			assert.Equal(t, tt.want, got)
+			Attack(ctx, tt.target, resCh, metricsCh, tt.opts)
 			assert.Equal(t, tt.wantResCount, len(resCh))
 		})
 	}

gui/keybinds.go

@@ -32,8 +32,7 @@ func attack(ctx context.Context, d *drawer, target string, opts attacker.Options
 	go d.redrawChart(ctx, requestNum)
 	go d.redrawGauge(ctx, requestNum)
 	go func(ctx context.Context, d *drawer, t string, o attacker.Options) {
-		metrics := attacker.Attack(ctx, t, d.chartCh, d.metricsCh, o)
-		d.metricsCh <- metrics
+		attacker.Attack(ctx, t, d.chartCh, d.metricsCh, o) // this blocks until attack finishes
 		d.chartCh <- &attacker.Result{End: true}
 		d.messageCh <- "Attack completed"
 	}(ctx, d, target, opts)