handle possible panic (#88)

Reviewed-on: https://gitea.com/gitea/act_runner/pulls/88
Reviewed-by: Jason Song <i@wolfogre.com>

poller/poller.go

@@ -54,24 +54,17 @@ func (p *Poller) Wait() {
 	p.routineGroup.Wait()
 }
 
-func (p *Poller) Poll(ctx context.Context) error {
-	l := log.WithField("func", "Poll")
-
-	for {
-		// check worker number
-		p.schedule()
-
-		select {
-		// wait worker ready
-		case <-p.ready:
-		case <-ctx.Done():
-			return nil
+func (p *Poller) handle(ctx context.Context, l *log.Entry) {
+	defer func() {
+		if r := recover(); r != nil {
+			l.Errorf("handle task panic: %+v", r)
 		}
-	LOOP:
+	}()
+
 	for {
 		select {
 		case <-ctx.Done():
-				break LOOP
+			return
 		default:
 			task, err := p.pollTask(ctx)
 			if task == nil || err != nil {
@@ -90,9 +83,25 @@ func (p *Poller) Poll(ctx context.Context) error {
 					l.Errorf("execute task: %v", err.Error())
 				}
 			})
-				break LOOP
+			return
 		}
 	}
+}
+
+func (p *Poller) Poll(ctx context.Context) error {
+	l := log.WithField("func", "Poll")
+
+	for {
+		// check worker number
+		p.schedule()
+
+		select {
+		// wait worker ready
+		case <-p.ready:
+		case <-ctx.Done():
+			return nil
+		}
+		p.handle(ctx, l)
 	}
 }