fix: expose metrics for VPA objects with empty target refs

Signed-off-by: m.nabokikh <maksim.nabokikh@flant.com>

Author: nabokihms

internal/store/verticalpodautoscaler.go

@@ -19,6 +19,7 @@ package store
 import (
 	"context"
 
+	k8sautoscaling "k8s.io/api/autoscaling/v1"
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -274,16 +275,18 @@ func vpaResourcesToMetrics(containerName string, resources v1.ResourceList) []*m
 func wrapVPAFunc(f func(*autoscaling.VerticalPodAutoscaler) *metric.Family) func(interface{}) *metric.Family {
 	return func(obj interface{}) *metric.Family {
 		vpa := obj.(*autoscaling.VerticalPodAutoscaler)
+
+		metricFamily := f(vpa)
 		targetRef := vpa.Spec.TargetRef
 
 		// targetRef was not a mandatory field, which can lead to a nil pointer exception here.
-		// Since it is pointless to have a VPA object without target ref, skip exporting metrics.
+		// However, we still want to expose metrics to be able:
+		// * to alert about VPA objects without target refs
+		// * to count the right amount of VPA objects in a cluster
 		if targetRef == nil {
-			return &metric.Family{}
+			targetRef = &k8sautoscaling.CrossVersionObjectReference{}
 		}
 
-		metricFamily := f(vpa)
-
 		for _, m := range metricFamily.Metrics {
 			m.LabelKeys = append(descVerticalPodAutoscalerLabelsDefaultLabels, m.LabelKeys...)
 			m.LabelValues = append([]string{vpa.Namespace, vpa.Name, targetRef.APIVersion, targetRef.Kind, targetRef.Name}, m.LabelValues...)

internal/store/verticalpodautoscaler_test.go

@@ -169,7 +169,35 @@ func TestVPAStore(t *testing.T) {
 					},
 				},
 			},
-			Want: metadata,
+			Want: metadata + `
+				kube_verticalpodautoscaler_spec_resourcepolicy_container_policies_maxallowed{container="*",namespace="ns2",resource="cpu",target_api_version="",target_kind="",target_name="",unit="core",verticalpodautoscaler="vpa-without-target-ref"} 4
+				kube_verticalpodautoscaler_spec_resourcepolicy_container_policies_maxallowed{container="*",namespace="ns2",resource="memory",target_api_version="",target_kind="",target_name="",unit="byte",verticalpodautoscaler="vpa-without-target-ref"} 8.589934592e+09
+				kube_verticalpodautoscaler_spec_resourcepolicy_container_policies_minallowed{container="*",namespace="ns2",resource="cpu",target_api_version="",target_kind="",target_name="",unit="core",verticalpodautoscaler="vpa-without-target-ref"} 1
+				kube_verticalpodautoscaler_spec_resourcepolicy_container_policies_minallowed{container="*",namespace="ns2",resource="memory",target_api_version="",target_kind="",target_name="",unit="byte",verticalpodautoscaler="vpa-without-target-ref"} 4.294967296e+09
+				kube_verticalpodautoscaler_status_recommendation_containerrecommendations_lowerbound{container="container1",namespace="ns2",resource="cpu",target_api_version="",target_kind="",target_name="",unit="core",verticalpodautoscaler="vpa-without-target-ref"} 1
+				kube_verticalpodautoscaler_status_recommendation_containerrecommendations_lowerbound{container="container1",namespace="ns2",resource="memory",target_api_version="",target_kind="",target_name="",unit="byte",verticalpodautoscaler="vpa-without-target-ref"} 4.294967296e+09
+				kube_verticalpodautoscaler_status_recommendation_containerrecommendations_target{container="container1",namespace="ns2",resource="cpu",target_api_version="",target_kind="",target_name="",unit="core",verticalpodautoscaler="vpa-without-target-ref"} 3
+				kube_verticalpodautoscaler_status_recommendation_containerrecommendations_target{container="container1",namespace="ns2",resource="memory",target_api_version="",target_kind="",target_name="",unit="byte",verticalpodautoscaler="vpa-without-target-ref"} 7.516192768e+09
+				kube_verticalpodautoscaler_status_recommendation_containerrecommendations_uncappedtarget{container="container1",namespace="ns2",resource="cpu",target_api_version="",target_kind="",target_name="",unit="core",verticalpodautoscaler="vpa-without-target-ref"} 6
+				kube_verticalpodautoscaler_status_recommendation_containerrecommendations_uncappedtarget{container="container1",namespace="ns2",resource="memory",target_api_version="",target_kind="",target_name="",unit="byte",verticalpodautoscaler="vpa-without-target-ref"} 1.073741824e+10
+				kube_verticalpodautoscaler_status_recommendation_containerrecommendations_upperbound{container="container1",namespace="ns2",resource="cpu",target_api_version="",target_kind="",target_name="",unit="core",verticalpodautoscaler="vpa-without-target-ref"} 4
+				kube_verticalpodautoscaler_status_recommendation_containerrecommendations_upperbound{container="container1",namespace="ns2",resource="memory",target_api_version="",target_kind="",target_name="",unit="byte",verticalpodautoscaler="vpa-without-target-ref"} 8.589934592e+09				
+				kube_verticalpodautoscaler_labels{namespace="ns2",target_api_version="",target_kind="",target_name="",verticalpodautoscaler="vpa-without-target-ref"} 1
+				kube_verticalpodautoscaler_spec_updatepolicy_updatemode{namespace="ns2",target_api_version="",target_kind="",target_name="",update_mode="Auto",verticalpodautoscaler="vpa-without-target-ref"} 0
+				kube_verticalpodautoscaler_spec_updatepolicy_updatemode{namespace="ns2",target_api_version="",target_kind="",target_name="",update_mode="Initial",verticalpodautoscaler="vpa-without-target-ref"} 0
+				kube_verticalpodautoscaler_spec_updatepolicy_updatemode{namespace="ns2",target_api_version="",target_kind="",target_name="",update_mode="Off",verticalpodautoscaler="vpa-without-target-ref"} 0
+				kube_verticalpodautoscaler_spec_updatepolicy_updatemode{namespace="ns2",target_api_version="",target_kind="",target_name="",update_mode="Recreate",verticalpodautoscaler="vpa-without-target-ref"} 1
+			`,
+			MetricNames: []string{
+				"kube_verticalpodautoscaler_labels",
+				"kube_verticalpodautoscaler_spec_updatepolicy_updatemode",
+				"kube_verticalpodautoscaler_spec_resourcepolicy_container_policies_minallowed",
+				"kube_verticalpodautoscaler_spec_resourcepolicy_container_policies_maxallowed",
+				"kube_verticalpodautoscaler_status_recommendation_containerrecommendations_lowerbound",
+				"kube_verticalpodautoscaler_status_recommendation_containerrecommendations_upperbound",
+				"kube_verticalpodautoscaler_status_recommendation_containerrecommendations_target",
+				"kube_verticalpodautoscaler_status_recommendation_containerrecommendations_uncappedtarget",
+			},
 		},
 	}
 	for i, c := range cases {