From 03fd2f278a3a781b5fcf0f57e75699240e8c19d5 Mon Sep 17 00:00:00 2001
From: Brad Davidson <brad.davidson@rancher.com>
Date: Wed, 7 Dec 2022 18:08:53 +0000
Subject: [PATCH] Add utility functions for getting kubernetes client

Signed-off-by: Brad Davidson <brad.davidson@rancher.com>
(cherry picked from commit 3c324335b248c33568ef872c796af65ad31b3044)
---
 pkg/agent/run.go           | 13 +------------
 pkg/agent/tunnel/tunnel.go |  7 +------
 pkg/util/client.go         | 29 +++++++++++++++++++++++++++++
 3 files changed, 31 insertions(+), 18 deletions(-)
 create mode 100644 pkg/util/client.go

diff --git a/pkg/agent/run.go b/pkg/agent/run.go
index dacdf08f5c..815a696e0d 100644
--- a/pkg/agent/run.go
+++ b/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
diff --git a/pkg/agent/tunnel/tunnel.go b/pkg/agent/tunnel/tunnel.go
index bc08b60469..bc2b619878 100644
--- a/pkg/agent/tunnel/tunnel.go
+++ b/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)
-	if err != nil {
-		return err
-	}
-
-	client, err := kubernetes.NewForConfig(restConfig)
+	client, err := util.GetClientSet(config.AgentConfig.KubeConfigK3sController)
 	if err != nil {
 		return err
 	}
diff --git a/pkg/util/client.go b/pkg/util/client.go
new file mode 100644
index 0000000000..52c396e4c4
--- /dev/null
+++ b/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)
+}