diff --git a/staging/src/k8s.io/client-go/examples/leader-election/BUILD b/staging/src/k8s.io/client-go/examples/leader-election/BUILD index 23e009fe7de..29ee62bea51 100644 --- a/staging/src/k8s.io/client-go/examples/leader-election/BUILD +++ b/staging/src/k8s.io/client-go/examples/leader-election/BUILD @@ -23,7 +23,7 @@ go_library( "//staging/src/k8s.io/client-go/tools/clientcmd:go_default_library", "//staging/src/k8s.io/client-go/tools/leaderelection:go_default_library", "//staging/src/k8s.io/client-go/tools/leaderelection/resourcelock:go_default_library", - "//staging/src/k8s.io/client-go/transport:go_default_library", + "//vendor/github.com/google/uuid:go_default_library", "//vendor/k8s.io/klog:go_default_library", ], ) diff --git a/staging/src/k8s.io/client-go/examples/leader-election/README.md b/staging/src/k8s.io/client-go/examples/leader-election/README.md index 7a182c6ecc1..2a081d130bf 100644 --- a/staging/src/k8s.io/client-go/examples/leader-election/README.md +++ b/staging/src/k8s.io/client-go/examples/leader-election/README.md @@ -7,15 +7,16 @@ This example demonstrates how to use the leader election package. Run the following three commands in separate terminals. Each terminal needs a unique `id`. ```bash -# first terminal -go run *.go -kubeconfig=/my/config -logtostderr=true -id=1 +# first terminal +go run main.go -kubeconfig=/path/to/kubeconfig -logtostderr=true -lease-lock-name=example -lease-lock-namespace=default -id=1 -# second terminal -go run *.go -kubeconfig=/my/config -logtostderr=true -id=2 +# second terminal +go run main.go -kubeconfig=/path/to/kubeconfig -logtostderr=true -lease-lock-name=example -lease-lock-namespace=default -id=2 # third terminal -go run *.go -kubeconfig=/my/config -logtostderr=true -id=3 +go run main.go -kubeconfig=/path/to/kubeconfig -logtostderr=true -lease-lock-name=example -lease-lock-namespace=default -id=3 ``` + > You can ignore the `-kubeconfig` flag if you are running these commands in the Kubernetes cluster. Now kill the existing leader. You will see from the terminal outputs that one of the remaining two processes will be elected as the new leader. diff --git a/staging/src/k8s.io/client-go/examples/leader-election/main.go b/staging/src/k8s.io/client-go/examples/leader-election/main.go index 85539bf6995..e60fcf95f22 100644 --- a/staging/src/k8s.io/client-go/examples/leader-election/main.go +++ b/staging/src/k8s.io/client-go/examples/leader-election/main.go @@ -19,21 +19,18 @@ package main import ( "context" "flag" - "fmt" - "log" "os" "os/signal" - "strings" "syscall" "time" + "github.com/google/uuid" metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" clientset "k8s.io/client-go/kubernetes" "k8s.io/client-go/rest" "k8s.io/client-go/tools/clientcmd" "k8s.io/client-go/tools/leaderelection" "k8s.io/client-go/tools/leaderelection/resourcelock" - "k8s.io/client-go/transport" "k8s.io/klog" ) @@ -62,13 +59,16 @@ func main() { var id string flag.StringVar(&kubeconfig, "kubeconfig", "", "absolute path to the kubeconfig file") - flag.StringVar(&id, "id", "", "the holder identity name") - flag.StringVar(&leaseLockName, "lease-lock-name", "example", "the lease lock resource name") - flag.StringVar(&leaseLockNamespace, "lease-lock-namespace", "default", "the lease lock resource namespace") + flag.StringVar(&id, "id", uuid.New().String(), "the holder identity name") + flag.StringVar(&leaseLockName, "lease-lock-name", "", "the lease lock resource name") + flag.StringVar(&leaseLockNamespace, "lease-lock-namespace", "", "the lease lock resource namespace") flag.Parse() - if id == "" { - klog.Fatal("unable to get id (missing id flag).") + if leaseLockName == "" { + klog.Fatal("unable to get lease lock resource name (missing lease-lock-name flag).") + } + if leaseLockNamespace == "" { + klog.Fatal("unable to get lease lock resource namespace (missing lease-lock-namespace flag).") } // leader election uses the Kubernetes API by writing to a @@ -82,6 +82,29 @@ func main() { } client := clientset.NewForConfigOrDie(config) + run := func(ctx context.Context) { + // complete your controller loop here + klog.Info("Controller loop...") + + select {} + } + + // use a Go context so we can tell the leaderelection code when we + // want to step down + ctx, cancel := context.WithCancel(context.Background()) + defer cancel() + + // listen for interrupts or the Linux SIGTERM signal and cancel + // our context, which the leader election code will observe and + // step down + ch := make(chan os.Signal, 1) + signal.Notify(ch, os.Interrupt, syscall.SIGTERM) + go func() { + <-ch + klog.Info("Received termination, signaling shutdown") + cancel() + }() + // we use the Lease lock type since edits to Leases are less common // and fewer objects in the cluster watch "all Leases". lock := &resourcelock.LeaseLock{ @@ -95,25 +118,6 @@ func main() { }, } - // use a Go context so we can tell the leaderelection code when we - // want to step down - ctx, cancel := context.WithCancel(context.Background()) - defer cancel() - - // use a client that will stop allowing new requests once the context ends - config.Wrap(transport.ContextCanceller(ctx, fmt.Errorf("the leader is shutting down"))) - - // listen for interrupts or the Linux SIGTERM signal and cancel - // our context, which the leader election code will observe and - // step down - ch := make(chan os.Signal, 1) - signal.Notify(ch, os.Interrupt, syscall.SIGTERM) - go func() { - <-ch - log.Printf("Received termination, signaling shutdown") - cancel() - }() - // start the leader election code loop leaderelection.RunOrDie(ctx, leaderelection.LeaderElectionConfig{ Lock: lock, @@ -131,12 +135,12 @@ func main() { OnStartedLeading: func(ctx context.Context) { // we're notified when we start - this is where you would // usually put your code - klog.Infof("%s: leading", id) + run(ctx) }, OnStoppedLeading: func() { - // we can do cleanup here, or after the RunOrDie method - // returns - klog.Infof("%s: lost", id) + // we can do cleanup here + klog.Infof("leader lost: %s", id) + os.Exit(0) }, OnNewLeader: func(identity string) { // we're notified when new leader elected @@ -144,18 +148,8 @@ func main() { // I just got the lock return } - klog.Infof("new leader elected: %v", identity) + klog.Infof("new leader elected: %s", identity) }, }, }) - - // because the context is closed, the client should report errors - _, err = client.CoordinationV1().Leases(leaseLockNamespace).Get(leaseLockName, metav1.GetOptions{}) - if err == nil || !strings.Contains(err.Error(), "the leader is shutting down") { - log.Fatalf("%s: expected to get an error when trying to make a client call: %v", id, err) - } - - // we no longer hold the lease, so perform any cleanup and then - // exit - log.Printf("%s: done", id) } diff --git a/staging/src/k8s.io/client-go/go.mod b/staging/src/k8s.io/client-go/go.mod index f7f7b19f68f..8d097e0bc89 100644 --- a/staging/src/k8s.io/client-go/go.mod +++ b/staging/src/k8s.io/client-go/go.mod @@ -14,6 +14,7 @@ require ( github.com/golang/groupcache v0.0.0-20160516000752-02826c3e7903 github.com/golang/protobuf v1.3.1 github.com/google/gofuzz v1.0.0 + github.com/google/uuid v1.1.1 github.com/googleapis/gnostic v0.0.0-20170729233727-0c5108395e2d github.com/gophercloud/gophercloud v0.1.0 github.com/gregjones/httpcache v0.0.0-20170728041850-787624de3eb7 diff --git a/staging/src/k8s.io/client-go/go.sum b/staging/src/k8s.io/client-go/go.sum index f4ef569eb44..87029ef74d7 100644 --- a/staging/src/k8s.io/client-go/go.sum +++ b/staging/src/k8s.io/client-go/go.sum @@ -64,6 +64,7 @@ github.com/google/gofuzz v1.0.0 h1:A8PeW59pxE9IoFRqBp37U+mSNaQoZ46F1f0f863XSXw= github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg= github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs= github.com/google/pprof v0.0.0-20181206194817-3ea8567a2e57/go.mod h1:zfwlbNMJ+OItoe0UupaVj+oy1omPYYDuagoSzA8v9mc= +github.com/google/uuid v1.1.1 h1:Gkbcsh/GbpXz7lPftLA3P6TYMwjCLYm83jiFQZF/3gY= github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo= github.com/googleapis/gax-go/v2 v2.0.4/go.mod h1:0Wqv26UfaUD9n4G6kQubkQ+KchISgw+vpHVxEJEs9eg= github.com/googleapis/gnostic v0.0.0-20170729233727-0c5108395e2d h1:7XGaL1e6bYS1yIonGp9761ExpPPV1ui0SAC59Yube9k=