// selector is the string-encoded form of a standard kubernetes label selector for the given metric.
  // When set, it is passed as an additional parameter to the metrics server for more specific metrics scoping
  // When unset, just the metricName will be used to gather metrics.
  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.LabelSelector selector = 4;

`foo=bar,istio=ingressgateway`:

```yaml
name: my-custom-gateway # Override the name to match existing resources
labels:
  app: "" # Unset default app selector label
  istio: ingressgateway # override default istio selector label
  foo: bar # Add the existing custom selector label
```

#### Migrating an existing Helm release

		// Make sure default and revisions do not cross
		mustNotSelect(t, mustGetLabels(t, serviceRev, "spec.selector"), podLabels)
		mustNotSelect(t, mustGetLabels(t, service, "spec.selector"), podLabelsRev)
		mustNotSelect(t, mustGetLabels(t, pdbRev, "spec.selector.matchLabels"), podLabels)
		mustNotSelect(t, mustGetLabels(t, pdb, "spec.selector.matchLabels"), podLabelsRev)

		// Make sure the scaleTargetRef points to the correct Deployment

  repeated HorizontalPodAutoscalerCondition conditions = 6;
}

// MetricIdentifier defines the name and optionally selector for a metric
message MetricIdentifier {
  // name is the name of the given metric
  optional string name = 1;

  // selector is the string-encoded form of a standard kubernetes label selector for the given metric

  // zero and not specified. Defaults to 1.
  // +optional
  optional int32 replicas = 1;

  // selector is the label selector for pods. Existing ReplicaSets whose pods are
  // selected by this will be the ones affected by this deployment.
  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.LabelSelector selector = 2;

  // Template describes the pods that will be created.

}

func mustSelect(t test.Failer, selector map[string]string, labels map[string]string) {
	t.Helper()
	kselector := labels2.Set(selector).AsSelectorPreValidated()
	if !kselector.Matches(labels2.Set(labels)) {
		t.Fatalf("%v does not select %v", selector, labels)
	}
}

func mustNotSelect(t test.Failer, selector map[string]string, labels map[string]string) {
	t.Helper()

apiVersion: policy/v1
kind: PodDisruptionBudget
metadata:
  name: {{ include "gateway.name" . }}
  namespace: {{ .Release.Namespace }}
  labels:
    {{- include "gateway.labels" . | nindent 4}}
spec:
  selector:
    matchLabels:
  {{- include "gateway.selectorLabels" . | nindent 6 }}
  {{- with .Values.podDisruptionBudget }}
    {{- toYaml . | nindent 2 }}
  {{- end }}

apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello
spec:
  replicas: 7
  selector:
    matchLabels:
      app: hello
      tier: backend
      track: stable
  template:
    metadata:
      labels:
        app: hello
        tier: backend
        track: stable
    spec:
      containers:
        - name: hello
          image: "fake.docker.io/google-samples/hello-go-gke:1.0"
          ports:

  // budget.
  // A null selector selects no pods.
  // An empty selector ({}) also selects no pods, which differs from standard behavior of selecting all pods.
  // In policy/v1, an empty selector will select all pods in the namespace.
  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.LabelSelector selector = 2;

  // An eviction is allowed if at most "maxUnavailable" pods selected by

apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  name: hello
spec:
  replicas: 7
  selector:
    matchLabels:
      app: hello
      tier: backend
      track: stable
  strategy: {}
  template:
    metadata:
      annotations:
        prometheus.io/path: /stats/prometheus
        prometheus.io/port: "15020"
        prometheus.io/scrape: "true"