Introduce metrics library

README.md

@@ -49,6 +49,10 @@ Note that the external-resizer does not scale with more replicas. Only one exter
 
 * `--workers <num>`: Number of simultaneously running `ControllerExpandVolume` operations. Default value is `10`.
 
+* `--metrics-address`: The TCP network address where the prometheus metrics endpoint will run (example: `:8080` which corresponds to port 8080 on local host). The default is empty string, which means metrics endpoint is disabled.
+
+* `--metrics-path`: The HTTP path where prometheus metrics will be exposed. Default is `/metrics`.
+
 #### Other recognized arguments
 
 * `--kubeconfig <path>`: Path to Kubernetes client configuration that the external-resizer uses to connect to Kubernetes API server. When omitted, default token provided by Kubernetes will be used. This option is useful only when the external-resizer does not run as a Kubernetes pod, e.g. for debugging. Either this or `--master` needs to be set if the external-resizer is being run out of cluster.

cmd/csi-resizer/main.go

@@ -46,6 +46,9 @@ var (
 	enableLeaderElection    = flag.Bool("leader-election", false, "Enable leader election.")
 	leaderElectionNamespace = flag.String("leader-election-namespace", "", "Namespace where the leader election resource lives. Defaults to the pod namespace if not set.")
 
+	metricsAddress = flag.String("metrics-address", "", "The TCP network address where the prometheus metrics endpoint will listen (example: `:8080`). The default is empty string, which means metrics endpoint is disabled.")
+	metricsPath    = flag.String("metrics-path", "/metrics", "The HTTP path where prometheus metrics will be exposed. Default is `/metrics`.")
+
 	version = "unknown"
 )
 
@@ -67,7 +70,13 @@ func main() {
 
 	informerFactory := informers.NewSharedInformerFactory(kubeClient, *resyncPeriod)
 
-	csiResizer, err := resizer.NewResizer(*csiAddress, *csiTimeout, kubeClient, informerFactory)
+	csiResizer, err := resizer.NewResizer(
+		*csiAddress,
+		*csiTimeout,
+		kubeClient,
+		informerFactory,
+		*metricsAddress,
+		*metricsPath)
 	if err != nil {
 		klog.Fatal(err.Error())
 	}

pkg/controller/controller_test.go

@@ -6,10 +6,11 @@ import (
 	"testing"
 	"time"
 
+	"github.com/kubernetes-csi/csi-lib-utils/metrics"
 	"github.com/kubernetes-csi/external-resizer/pkg/csi"
 	"github.com/kubernetes-csi/external-resizer/pkg/resizer"
 
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -114,7 +115,10 @@ func TestController(t *testing.T) {
 			}
 		}
 
-		csiResizer, err := resizer.NewResizerFromClient(client, 15*time.Second, kubeClient, informerFactory)
+		metricsManager := metrics.NewCSIMetricsManager("" /* driverName */)
+		metricsAddress := ""
+		metricsPath := ""
+		csiResizer, err := resizer.NewResizerFromClient(client, 15*time.Second, kubeClient, informerFactory, metricsManager, metricsAddress, metricsPath)
 		if err != nil {
 			t.Fatalf("Test %s: Unable to create resizer: %v", test.Name, err)
 		}

pkg/csi/client.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/container-storage-interface/spec/lib/go/csi"
 	"github.com/kubernetes-csi/csi-lib-utils/connection"
+	"github.com/kubernetes-csi/csi-lib-utils/metrics"
 	csirpc "github.com/kubernetes-csi/csi-lib-utils/rpc"
 	"google.golang.org/grpc"
 )
@@ -51,8 +52,8 @@ type Client interface {
 }
 
 // New creates a new CSI client.
-func New(address string, timeout time.Duration) (Client, error) {
-	conn, err := connection.Connect(address, connection.OnConnectionLoss(connection.ExitOnConnectionLoss()))
+func New(address string, timeout time.Duration, metricsManager metrics.CSIMetricsManager) (Client, error) {
+	conn, err := connection.Connect(address, metricsManager, connection.OnConnectionLoss(connection.ExitOnConnectionLoss()))
 	if err != nil {
 		return nil, fmt.Errorf("failed to connect to CSI driver: %v", err)
 	}

pkg/resizer/csi_resizer.go

@@ -22,10 +22,11 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/kubernetes-csi/csi-lib-utils/metrics"
 	"github.com/kubernetes-csi/external-resizer/pkg/csi"
 	"github.com/kubernetes-csi/external-resizer/pkg/util"
 
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/informers"
@@ -45,24 +46,39 @@ func NewResizer(
 	address string,
 	timeout time.Duration,
 	k8sClient kubernetes.Interface,
-	informerFactory informers.SharedInformerFactory) (Resizer, error) {
-	csiClient, err := csi.New(address, timeout)
+	informerFactory informers.SharedInformerFactory,
+	metricsAddress, metricsPath string) (Resizer, error) {
+	metricsManager := metrics.NewCSIMetricsManager("" /* driverName */)
+	csiClient, err := csi.New(address, timeout, metricsManager)
 	if err != nil {
 		return nil, err
 	}
-	return NewResizerFromClient(csiClient, timeout, k8sClient, informerFactory)
+	return NewResizerFromClient(
+		csiClient,
+		timeout,
+		k8sClient,
+		informerFactory,
+		metricsManager,
+		metricsAddress,
+		metricsPath)
 }
 
 func NewResizerFromClient(
 	csiClient csi.Client,
 	timeout time.Duration,
 	k8sClient kubernetes.Interface,
-	informerFactory informers.SharedInformerFactory) (Resizer, error) {
+	informerFactory informers.SharedInformerFactory,
+	metricsManager metrics.CSIMetricsManager,
+	metricsAddress, metricsPath string) (Resizer, error) {
 	driverName, err := getDriverName(csiClient, timeout)
 	if err != nil {
 		return nil, fmt.Errorf("get driver name failed: %v", err)
 	}
 
+	klog.V(2).Infof("CSI driver name: %q", driverName)
+	metricsManager.SetDriverName(driverName)
+	metricsManager.StartMetricsEndpoint(metricsAddress, metricsPath)
+
 	supportControllerService, err := supportsPluginControllerService(csiClient, timeout)
 	if err != nil {
 		return nil, fmt.Errorf("failed to check if plugin supports controller service: %v", err)

pkg/resizer/csi_resizer_test.go

@@ -6,9 +6,10 @@ import (
 	"testing"
 	"time"
 
+	"github.com/kubernetes-csi/csi-lib-utils/metrics"
 	"github.com/kubernetes-csi/external-resizer/pkg/csi"
 	"github.com/kubernetes-csi/external-resizer/pkg/util"
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/informers"
@@ -59,8 +60,11 @@ func TestNewResizer(t *testing.T) {
 		},
 	} {
 		client := csi.NewMockClient("mock", c.SupportsNodeResize, c.SupportsControllerResize, c.SupportsPluginControllerService)
+		metricsManager := metrics.NewCSIMetricsManager("" /* driverName */)
+		metricsAddress := ""
+		metricsPath := ""
 		k8sClient, informerFactory := fakeK8s()
-		resizer, err := NewResizerFromClient(client, 0, k8sClient, informerFactory)
+		resizer, err := NewResizerFromClient(client, 0, k8sClient, informerFactory, metricsManager, metricsAddress, metricsPath)
 		if err != c.Error {
 			t.Errorf("Case %d: Unexpected error: wanted %v, got %v", i, c.Error, err)
 		}
@@ -166,7 +170,10 @@ func TestResizeMigratedPV(t *testing.T) {
 			driverName := tc.driverName
 			client := csi.NewMockClient(driverName, true, true, true)
 			k8sClient, informerFactory := fakeK8s()
-			resizer, err := NewResizerFromClient(client, 0, k8sClient, informerFactory)
+			metricsManager := metrics.NewCSIMetricsManager("" /* driverName */)
+			metricsAddress := ""
+			metricsPath := ""
+			resizer, err := NewResizerFromClient(client, 0, k8sClient, informerFactory, metricsManager, metricsAddress, metricsPath)
 			if err != nil {
 				t.Fatalf("Failed to create resizer: %v", err)
 			}
@@ -237,7 +244,10 @@ func TestCanSupport(t *testing.T) {
 			driverName := tc.driverName
 			client := csi.NewMockClient(driverName, true, true, true)
 			k8sClient, informerFactory := fakeK8s()
-			resizer, err := NewResizerFromClient(client, 0, k8sClient, informerFactory)
+			metricsManager := metrics.NewCSIMetricsManager("" /* driverName */)
+			metricsAddress := ""
+			metricsPath := ""
+			resizer, err := NewResizerFromClient(client, 0, k8sClient, informerFactory, metricsManager, metricsAddress, metricsPath)
 			if err != nil {
 				t.Fatalf("Failed to create resizer: %v", err)
 			}