use trace logging for context errors

runtime/poller.go

@@ -56,6 +56,10 @@ func (p *Poller) poll(ctx context.Context, thread int) error {
 	// request a new build stage for execution from the central
 	// build server.
 	stage, err := p.Client.Request(ctx, p.Filter)
+	if err == context.Canceled || err == context.DeadlineExceeded {
+		log.WithError(err).Trace("no stage returned")
+		return nil
+	}
 	if err != nil {
 		log.WithError(err).Error("cannot request stage")
 		return err