constellation-node-operator: don't bail out on listing errors

If the GCP project has scaling groups for which our checks can't be performed (which is the case for regional scaling groups, as they "don't exist" for the operator, if deployed in another region) . In that case, we should not bail out directly but go on with the next group. An error should only be thrown if there are no matching groups at all.

operators/constellation-node-operator/internal/cloud/gcp/client/scalinggroup.go

@@ -129,7 +129,7 @@ func (c *Client) ListScalingGroups(ctx context.Context, uid string) ([]cspapi.Sc
 			}
 			template, err := c.instanceTemplateAPI.Get(c.projectID, templateURI[len(templateURI)-1])
 			if err != nil {
-				return nil, fmt.Errorf("getting instance template: %w", err)
+				continue
 			}
 			if template.Properties == nil || template.Properties.Labels == nil {
 				continue
@@ -140,14 +140,14 @@ func (c *Client) ListScalingGroups(ctx context.Context, uid string) ([]cspapi.Sc
 
 			groupID, err := c.canonicalInstanceGroupID(ctx, *grpManager.SelfLink)
 			if err != nil {
-				return nil, fmt.Errorf("normalizing instance group ID: %w", err)
+				continue
 			}
 
 			role := updatev1alpha1.NodeRoleFromString(template.Properties.Labels["constellation-role"])
 
 			name, err := c.GetScalingGroupName(groupID)
 			if err != nil {
-				return nil, fmt.Errorf("getting scaling group name: %w", err)
+				continue
 			}
 
 			nodeGroupName := template.Properties.Labels["constellation-node-group"]
@@ -164,7 +164,7 @@ func (c *Client) ListScalingGroups(ctx context.Context, uid string) ([]cspapi.Sc
 
 			autoscalerGroupName, err := c.GetAutoscalingGroupName(groupID)
 			if err != nil {
-				return nil, fmt.Errorf("getting autoscaling group name: %w", err)
+				continue
 			}
 
 			results = append(results, cspapi.ScalingGroup{
@@ -176,6 +176,11 @@ func (c *Client) ListScalingGroups(ctx context.Context, uid string) ([]cspapi.Sc
 			})
 		}
 	}
+
+	if len(results) == 0 {
+		return nil, errors.New("no matching scaling groups found")
+	}
+
 	return results, nil
 }