Bump csi-lib-utils to v0.9.0

vendor/github.com/kubernetes-csi/csi-lib-utils/leaderelection/leader_election.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"fmt"
 	"io/ioutil"
+	"net/http"
 	"os"
 	"regexp"
 	"strings"
@@ -32,13 +33,21 @@ import (
 	"k8s.io/client-go/tools/leaderelection"
 	"k8s.io/client-go/tools/leaderelection/resourcelock"
 	"k8s.io/client-go/tools/record"
-	"k8s.io/klog"
+	"k8s.io/klog/v2"
 )
 
 const (
 	defaultLeaseDuration = 15 * time.Second
 	defaultRenewDeadline = 10 * time.Second
 	defaultRetryPeriod   = 5 * time.Second
+
+	DefaultHealthCheckTimeout = 20 * time.Second
+
+	// HealthCheckerAddress is the address at which the leader election health
+	// checker reports status.
+	// The caller sidecar should document this address in appropriate flag
+	// descriptions.
+	HealthCheckerAddress = "/healthz/leader-election"
 )
 
 // leaderElection is a convenience wrapper around client-go's leader election library.
@@ -55,6 +64,9 @@ type leaderElection struct {
 	// valid options are resourcelock.LeasesResourceLock, resourcelock.EndpointsResourceLock,
 	// and resourcelock.ConfigMapsResourceLock
 	resourceLock string
+	// healthCheck reports unhealthy if leader election fails to renew leadership
+	// within a timeout period.
+	healthCheck *leaderelection.HealthzAdaptor
 
 	leaseDuration time.Duration
 	renewDeadline time.Duration
@@ -134,6 +146,27 @@ func (l *leaderElection) WithContext(ctx context.Context) {
 	l.ctx = ctx
 }
 
+// Server represents any type that could serve HTTP requests for the leader
+// election health check endpoint.
+type Server interface {
+	Handle(pattern string, handler http.Handler)
+}
+
+// PrepareHealthCheck creates a health check for this leader election object
+// with the given healthCheckTimeout and registers its HTTP handler to the given
+// server at the path specified by the constant "healthCheckerAddress".
+// healthCheckTimeout determines the max duration beyond lease expiration
+// allowed before reporting unhealthy.
+// The caller sidecar should document the handler address in appropriate flag
+// descriptions.
+func (l *leaderElection) PrepareHealthCheck(
+	s Server,
+	healthCheckTimeout time.Duration) {
+
+	l.healthCheck = leaderelection.NewLeaderHealthzAdaptor(healthCheckTimeout)
+	s.Handle(HealthCheckerAddress, adaptCheckToHandler(l.healthCheck.Check))
+}
+
 func (l *leaderElection) Run() error {
 	if l.identity == "" {
 		id, err := defaultLeaderElectionIdentity()
@@ -179,6 +212,7 @@ func (l *leaderElection) Run() error {
 				klog.V(3).Infof("new leader detected, current leader: %s", identity)
 			},
 		},
+		WatchDog: l.healthCheck,
 	}
 
 	ctx := l.ctx
@@ -220,3 +254,15 @@ func inClusterNamespace() string {
 
 	return "default"
 }
+
+// adaptCheckToHandler returns an http.HandlerFunc that serves the provided checks.
+func adaptCheckToHandler(c func(r *http.Request) error) http.HandlerFunc {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		err := c(r)
+		if err != nil {
+			http.Error(w, fmt.Sprintf("internal server error: %v", err), http.StatusInternalServerError)
+		} else {
+			fmt.Fprint(w, "ok")
+		}
+	})
+}