add some error handling

Author: yuchen-db

main.go

@@ -654,17 +654,20 @@ func (c *controller) sync(ctx context.Context) {
 
 		if !ok {
 			level.Error(c.logger).Log("msg", "failed type assertion from expected StatefulSet")
+			continue
 		}
 
 		hashring, ok := sts.Labels[hashringLabelKey]
 		if !ok {
+			level.Error(c.logger).Log("msg", "failed to get hashring label from StatefulSet", "sts", sts.Name)
 			continue
 		}
 
 		stsReplica, exist := c.replicas[sts.Name]
 		desiredReplicas, err := c.getStsDesiredReplicas(ctx, sts)
-		if err != nil {
+		if err != nil || desiredReplicas == 0 {
 			level.Error(c.logger).Log("msg", "failed to get desired replicas for Statefulset", "sts", sts.Name, "err", err)
+			continue
 		}
 		stsReplicas[sts.Name] = desiredReplicas
 		// If hashring is not initialized, need to wait for all pods ready within statefulset before generating hashring