Add metrics support

Author: bswartz

example/hello-populator/deploy.yaml

@@ -66,6 +66,11 @@ spec:
           args:
             - --mode=controller
             - --image-name=k8s.gcr.io/sig-storage/hello-populator:v0.1.0
+            - --http-endpoint=:8080
+          ports:
+            - containerPort: 8080
+              name: http-endpoint
+              protocol: TCP
 ---
 kind: VolumePopulator
 apiVersion: populator.storage.k8s.io/v1alpha1

example/hello-populator/main.go

@@ -22,12 +22,13 @@ import (
 	"os"
 	"strings"
 
-	populator_machinery "github.com/kubernetes-csi/lib-volume-populator/populator-machinery"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/klog/v2"
+
+	populator_machinery "github.com/kubernetes-csi/lib-volume-populator/populator-machinery"
 )
 
 const (
@@ -43,6 +44,8 @@ func main() {
 		mode         string
 		fileName     string
 		fileContents string
+		httpEndpoint string
+		metricsPath  string
 		masterURL    string
 		kubeconfig   string
 		imageName    string
@@ -58,6 +61,10 @@ func main() {
 	flag.StringVar(&kubeconfig, "kubeconfig", "", "Path to a kubeconfig. Only required if out-of-cluster.")
 	flag.StringVar(&masterURL, "master", "", "The address of the Kubernetes API server. Overrides any value in kubeconfig. Only required if out-of-cluster.")
 	flag.StringVar(&imageName, "image-name", "", "Image to use for populating")
+	// Metrics args
+	flag.StringVar(&httpEndpoint, "http-endpoint", "", "The TCP network address where the HTTP server for diagnostics, including metrics and leader election health check, will listen (example: `:8080`). The default is empty string, which means the server is disabled.")
+	flag.StringVar(&metricsPath, "metrics-path", "/metrics", "The HTTP path where prometheus metrics will be exposed. Default is `/metrics`.")
+	// Other args
 	flag.BoolVar(&showVersion, "version", false, "display the version string")
 	flag.StringVar(&namespace, "namespace", "hello", "Namespace to deploy controller")
 	flag.Parse()
@@ -79,7 +86,7 @@ func main() {
 			gk  = schema.GroupKind{Group: groupName, Kind: kind}
 			gvr = schema.GroupVersionResource{Group: groupName, Version: apiVersion, Resource: resource}
 		)
-		populator_machinery.RunController(masterURL, kubeconfig, imageName,
+		populator_machinery.RunController(masterURL, kubeconfig, imageName, httpEndpoint, metricsPath,
 			namespace, prefix, gk, gvr, mountPath, devicePath, getPopulatorPodArgs)
 	case "populate":
 		populate(fileName, fileContents)

go.mod

@@ -1,10 +1,50 @@
 module github.com/kubernetes-csi/lib-volume-populator
 
-go 1.16
+go 1.17
 
 require (
-	k8s.io/api v0.23.4
-	k8s.io/apimachinery v0.23.4
-	k8s.io/client-go v0.23.4
+	github.com/prometheus/client_model v0.2.0
+	github.com/prometheus/common v0.28.0
+	k8s.io/api v0.23.5
+	k8s.io/apimachinery v0.23.5
+	k8s.io/client-go v0.23.5
+	k8s.io/component-base v0.23.5
 	k8s.io/klog/v2 v2.30.0
 )
+
+require (
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/blang/semver v3.5.1+incompatible // indirect
+	github.com/cespare/xxhash/v2 v2.1.1 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/go-logr/logr v1.2.0 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/google/go-cmp v0.5.5 // indirect
+	github.com/google/gofuzz v1.1.0 // indirect
+	github.com/googleapis/gnostic v0.5.5 // indirect
+	github.com/imdario/mergo v0.3.5 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.2-0.20181231171920-c182affec369 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/prometheus/client_golang v1.11.0 // indirect
+	github.com/prometheus/procfs v0.6.0 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	golang.org/x/net v0.0.0-20211209124913-491a49abca63 // indirect
+	golang.org/x/oauth2 v0.0.0-20210819190943-2bc19b11175f // indirect
+	golang.org/x/sys v0.0.0-20210831042530-f4d43177bf5e // indirect
+	golang.org/x/term v0.0.0-20210615171337-6886f2dfbf5b // indirect
+	golang.org/x/text v0.3.7 // indirect
+	golang.org/x/time v0.0.0-20210723032227-1f47c861a9ac // indirect
+	google.golang.org/appengine v1.6.7 // indirect
+	google.golang.org/protobuf v1.27.1 // indirect
+	gopkg.in/inf.v0 v0.9.1 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
+	k8s.io/kube-openapi v0.0.0-20211115234752-e816edb12b65 // indirect
+	k8s.io/utils v0.0.0-20211116205334-6203023598ed // indirect
+	sigs.k8s.io/json v0.0.0-20211020170558-c049b76a60c6 // indirect
+	sigs.k8s.io/structured-merge-diff/v4 v4.2.1 // indirect
+	sigs.k8s.io/yaml v1.2.0 // indirect
+)