discovery: fix more error logs on context cancelation (#6133)

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

discovery/consul/consul.go

@@ -357,6 +357,13 @@ func (d *Discovery) watchServices(ctx context.Context, ch chan<- []*targetgroup.
 	elapsed := time.Since(t0)
 	rpcDuration.WithLabelValues("catalog", "services").Observe(elapsed.Seconds())
 
+	// Check the context before in order to exit early.
+	select {
+	case <-ctx.Done():
+		return
+	default:
+	}
+
 	if err != nil {
 		level.Error(d.logger).Log("msg", "Error refreshing service list", "err", err)
 		rpcFailuresCount.Inc()

discovery/dns/dns.go

@@ -151,7 +151,7 @@ func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 	wg.Add(len(d.names))
 	for _, name := range d.names {
 		go func(n string) {
-			if err := d.refreshOne(ctx, n, ch); err != nil {
+			if err := d.refreshOne(ctx, n, ch); err != nil && err != context.Canceled {
 				level.Error(d.logger).Log("msg", "Error refreshing DNS targets", "err", err)
 			}
 			wg.Done()