Add utility functions for getting kubernetes client

Signed-off-by: Brad Davidson <brad.davidson@rancher.com>
(cherry picked from commit 3c324335b2)

pkg/agent/run.go

@@ -40,10 +40,8 @@ import (
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/watch"
-	"k8s.io/client-go/kubernetes"
 	typedcorev1 "k8s.io/client-go/kubernetes/typed/core/v1"
 	"k8s.io/client-go/tools/cache"
-	"k8s.io/client-go/tools/clientcmd"
 	toolswatch "k8s.io/client-go/tools/watch"
 	app2 "k8s.io/kubernetes/cmd/kube-proxy/app"
 	kubeproxyconfig "k8s.io/kubernetes/pkg/proxy/apis/config"
@@ -137,7 +135,7 @@ func run(ctx context.Context, cfg cmds.Agent, proxy proxy.Proxy) error {
 		return errors.Wrap(err, "failed to wait for apiserver ready")
 	}
 
-	coreClient, err := coreClient(nodeConfig.AgentConfig.KubeConfigKubelet)
+	coreClient, err := util.GetClientSet(nodeConfig.AgentConfig.KubeConfigKubelet)
 	if err != nil {
 		return err
 	}
@@ -213,15 +211,6 @@ func getConntrackConfig(nodeConfig *daemonconfig.Node) (*kubeproxyconfig.KubePro
 	return ctConfig, nil
 }
 
-func coreClient(cfg string) (kubernetes.Interface, error) {
-	restConfig, err := clientcmd.BuildConfigFromFlags("", cfg)
-	if err != nil {
-		return nil, err
-	}
-
-	return kubernetes.NewForConfig(restConfig)
-}
-
 // RunStandalone bootstraps the executor, but does not run the kubelet or containerd.
 // This allows other bits of code that expect the executor to be set up properly to function
 // even when the agent is disabled. It will only return in case of error or context

pkg/agent/tunnel/tunnel.go

@@ -56,12 +56,7 @@ func (p *podEntry) Network() net.IPNet {
 }
 
 func Setup(ctx context.Context, config *daemonconfig.Node, proxy proxy.Proxy) error {
-	restConfig, err := clientcmd.BuildConfigFromFlags("", config.AgentConfig.KubeConfigK3sController)
+	client, err := util.GetClientSet(config.AgentConfig.KubeConfigK3sController)
-	if err != nil {
-		return err
-	}
-
-	client, err := kubernetes.NewForConfig(restConfig)
 	if err != nil {
 		return err
 	}

pkg/util/client.go

@@ -0,0 +1,29 @@
+package util
+
+import (
+	"github.com/k3s-io/k3s/pkg/datadir"
+	clientset "k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/tools/clientcmd"
+)
+
+// GetKubeConfigPath can be used to search for a kubeconfig in standard
+// locations if an empty string is passed. If a non-empty string is passed,
+// that path is used.
+func GetKubeConfigPath(file string) string {
+	if file != "" {
+		return file
+	}
+	rules := clientcmd.NewDefaultClientConfigLoadingRules()
+	rules.Precedence = append([]string{datadir.GlobalConfig}, rules.Precedence...)
+	return rules.GetDefaultFilename()
+}
+
+// GetClientSet creates a Kubernetes client from the kubeconfig at the provided path.
+func GetClientSet(file string) (clientset.Interface, error) {
+	restConfig, err := clientcmd.BuildConfigFromFlags("", file)
+	if err != nil {
+		return nil, err
+	}
+
+	return clientset.NewForConfig(restConfig)
+}