Add telemetry collection of deployment replica count (#1551)

Problem: Want to collect deployment replica count as a telemetry datapoint.

Solution: Collect deployment replica count.

Author: bjee19

cmd/gateway/commands.go

@@ -153,6 +153,7 @@ func createStaticModeCommand() *cobra.Command {
 					PodIP:       podIP,
 					ServiceName: serviceName.value,
 					Namespace:   namespace,
+					Name:        podName,
 				},
 				HealthConfig: config.HealthConfig{
 					Enabled: !disableHealth,

deploy/helm-chart/templates/rbac.yaml

@@ -21,19 +21,36 @@ rules:
   - namespaces
   - services
   - secrets
-  # FIXME(bjee19): make nodes permission dependent on telemetry being enabled.
-  # https://github.com/nginxinc/nginx-gateway-fabric/issues/1317.
-  - nodes
   verbs:
   - list
   - watch
+# FIXME(bjee19): make nodes, pods, replicasets permission dependent on telemetry being enabled.
+# https://github.com/nginxinc/nginx-gateway-fabric/issues/1317.
+- apiGroups:
+  - ""
+  resources:
+  - pods
+  verbs:
+  - get
+- apiGroups:
+  - ""
+  resources:
+  - nodes
+  verbs:
+  - list
 - apiGroups:
   - ""
   resources:
   - events
   verbs:
   - create
   - patch
+- apiGroups:
+  - apps
+  resources:
+  - replicasets
+  verbs:
+  - get
 - apiGroups:
   - discovery.k8s.io
   resources:

deploy/manifests/nginx-gateway.yaml

@@ -32,19 +32,36 @@ rules:
   - namespaces
   - services
   - secrets
-  # FIXME(bjee19): make nodes permission dependent on telemetry being enabled.
-  # https://github.com/nginxinc/nginx-gateway-fabric/issues/1317.
-  - nodes
   verbs:
   - list
   - watch
+# FIXME(bjee19): make nodes, pods, replicasets permission dependent on telemetry being enabled.
+# https://github.com/nginxinc/nginx-gateway-fabric/issues/1317.
+- apiGroups:
+  - ""
+  resources:
+  - pods
+  verbs:
+  - get
+- apiGroups:
+  - ""
+  resources:
+  - nodes
+  verbs:
+  - list
 - apiGroups:
   - ""
   resources:
   - events
   verbs:
   - create
   - patch
+- apiGroups:
+  - apps
+  resources:
+  - replicasets
+  verbs:
+  - get
 - apiGroups:
   - discovery.k8s.io
   resources:

internal/mode/static/config/config.go

@@ -48,6 +48,8 @@ type GatewayPodConfig struct {
 	ServiceName string
 	// Namespace is the namespace of this Pod.
 	Namespace string
+	// Name is the name of the Pod.
+	Name string
 }
 
 // MetricsConfig specifies the metrics config.

internal/mode/static/manager.go

@@ -8,6 +8,7 @@ import (
 	"github.com/go-logr/logr"
 	ngxclient "github.com/nginxinc/nginx-plus-go-client/client"
 	"github.com/prometheus/client_golang/prometheus"
+	appsv1 "k8s.io/api/apps/v1"
 	apiv1 "k8s.io/api/core/v1"
 	discoveryV1 "k8s.io/api/discovery/v1"
 	apiext "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
@@ -65,6 +66,7 @@ func init() {
 	utilruntime.Must(discoveryV1.AddToScheme(scheme))
 	utilruntime.Must(ngfAPI.AddToScheme(scheme))
 	utilruntime.Must(apiext.AddToScheme(scheme))
+	utilruntime.Must(appsv1.AddToScheme(scheme))
 }
 
 // nolint:gocyclo
@@ -214,10 +216,14 @@ func StartManager(cfg config.Config) error {
 	}
 
 	dataCollector := telemetry.NewDataCollectorImpl(telemetry.DataCollectorConfig{
-		K8sClientReader:     mgr.GetClient(),
+		K8sClientReader:     mgr.GetAPIReader(),
 		GraphGetter:         processor,
 		ConfigurationGetter: eventHandler,
 		Version:             cfg.Version,
+		PodNSName: types.NamespacedName{
+			Namespace: cfg.GatewayPodConfig.Namespace,
+			Name:      cfg.GatewayPodConfig.Name,
+		},
 	})
 	if err = mgr.Add(createTelemetryJob(cfg, dataCollector, nginxChecker.getReadyCh())); err != nil {
 		return fmt.Errorf("cannot register telemetry job: %w", err)

internal/mode/static/telemetry/collector.go

@@ -5,7 +5,9 @@ import (
 	"errors"
 	"fmt"
 
+	appsv1 "k8s.io/api/apps/v1"
 	v1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/types"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 
 	"github.com/nginxinc/nginx-gateway-fabric/internal/mode/static/state/dataplane"
@@ -49,6 +51,7 @@ type Data struct {
 	ProjectMetadata   ProjectMetadata
 	NodeCount         int
 	NGFResourceCounts NGFResourceCounts
+	NGFReplicaCount   int
 }
 
 // DataCollectorConfig holds configuration parameters for DataCollectorImpl.
@@ -61,6 +64,8 @@ type DataCollectorConfig struct {
 	ConfigurationGetter ConfigurationGetter
 	// Version is the NGF version.
 	Version string
+	// PodNSName is the NamespacedName of the NGF Pod.
+	PodNSName types.NamespacedName
 }
 
 // DataCollectorImpl is am implementation of DataCollector.
@@ -89,13 +94,19 @@ func (c DataCollectorImpl) Collect(ctx context.Context) (Data, error) {
 		return Data{}, fmt.Errorf("failed to collect NGF resource counts: %w", err)
 	}
 
+	ngfReplicaCount, err := collectNGFReplicaCount(ctx, c.cfg.K8sClientReader, c.cfg.PodNSName)
+	if err != nil {
+		return Data{}, fmt.Errorf("failed to collect NGF replica count: %w", err)
+	}
+
 	data := Data{
 		NodeCount:         nodeCount,
 		NGFResourceCounts: graphResourceCount,
 		ProjectMetadata: ProjectMetadata{
 			Name:    "NGF",
 			Version: c.cfg.Version,
 		},
+		NGFReplicaCount: ngfReplicaCount,
 	}
 
 	return data, nil
@@ -104,7 +115,7 @@ func (c DataCollectorImpl) Collect(ctx context.Context) (Data, error) {
 func collectNodeCount(ctx context.Context, k8sClient client.Reader) (int, error) {
 	var nodes v1.NodeList
 	if err := k8sClient.List(ctx, &nodes); err != nil {
-		return 0, err
+		return 0, fmt.Errorf("failed to get NodeList: %w", err)
 	}
 
 	return len(nodes.Items), nil
@@ -147,3 +158,38 @@ func collectGraphResourceCount(
 
 	return ngfResourceCounts, nil
 }
+
+func collectNGFReplicaCount(ctx context.Context, k8sClient client.Reader, podNSName types.NamespacedName) (int, error) {
+	var pod v1.Pod
+	if err := k8sClient.Get(
+		ctx,
+		types.NamespacedName{Namespace: podNSName.Namespace, Name: podNSName.Name},
+		&pod,
+	); err != nil {
+		return 0, fmt.Errorf("failed to get NGF Pod: %w", err)
+	}
+
+	podOwnerRefs := pod.GetOwnerReferences()
+	if len(podOwnerRefs) != 1 {
+		return 0, fmt.Errorf("expected one owner reference of the NGF Pod, got %d", len(podOwnerRefs))
+	}
+
+	if podOwnerRefs[0].Kind != "ReplicaSet" {
+		return 0, fmt.Errorf("expected pod owner reference to be ReplicaSet, got %s", podOwnerRefs[0].Kind)
+	}
+
+	var replicaSet appsv1.ReplicaSet
+	if err := k8sClient.Get(
+		ctx,
+		types.NamespacedName{Namespace: podNSName.Namespace, Name: podOwnerRefs[0].Name},
+		&replicaSet,
+	); err != nil {
+		return 0, fmt.Errorf("failed to get NGF Pod's ReplicaSet: %w", err)
+	}
+
+	if replicaSet.Spec.Replicas == nil {
+		return 0, errors.New("replica set replicas was nil")
+	}
+
+	return int(*replicaSet.Spec.Replicas), nil
+}