Add new way to generate leader election lock

Author: jprzychodzen

staging/src/k8s.io/client-go/tools/leaderelection/resourcelock/BUILD

@@ -18,8 +18,10 @@ go_library(
         "//staging/src/k8s.io/apimachinery/pkg/api/errors:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/runtime:go_default_library",
+        "//staging/src/k8s.io/client-go/kubernetes:go_default_library",
         "//staging/src/k8s.io/client-go/kubernetes/typed/coordination/v1:go_default_library",
         "//staging/src/k8s.io/client-go/kubernetes/typed/core/v1:go_default_library",
+        "//staging/src/k8s.io/client-go/rest:go_default_library",
     ],
 )
 

staging/src/k8s.io/client-go/tools/leaderelection/resourcelock/interface.go

@@ -19,6 +19,9 @@ package resourcelock
 import (
 	"context"
 	"fmt"
+	clientset "k8s.io/client-go/kubernetes"
+	restclient "k8s.io/client-go/rest"
+	"time"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -140,3 +143,16 @@ func New(lockType string, ns string, name string, coreClient corev1.CoreV1Interf
 		return nil, fmt.Errorf("Invalid lock-type %s", lockType)
 	}
 }
+
+// NewFromKubeconfig will create a lock of a given type according to the input parameters.
+func NewFromKubeconfig(lockType string, ns string, name string, rlc ResourceLockConfig, kubeconfig *restclient.Config, renewDeadline time.Duration) (Interface, error) {
+	// shallow copy, do not modify the kubeconfig
+	config := *kubeconfig
+	timeout := ((renewDeadline / time.Millisecond) / 2) * time.Millisecond
+	if timeout < time.Second {
+		timeout = time.Second
+	}
+	config.Timeout = timeout
+	leaderElectionClient := clientset.NewForConfigOrDie(restclient.AddUserAgent(&config, "leader-election"))
+	return New(lockType, ns, name, leaderElectionClient.CoreV1(), leaderElectionClient.CoordinationV1(), rlc)
+}