Add kubeconfig flag for k8s plugin (#296)

plugin/kubernetes/README.md

@@ -8,6 +8,8 @@ this plugin is inpsired by the [first version kubernetes plugin](https://github.
 
 Start plugin with flag `--all-namespaces` or environment variable `SSHPIPERD_KUBERNETES_ALL_NAMESPACES=true` for cluster-wide usage, or it will listen to the namespace where it is in by default.
 
+Start plugin with flag `--kubeconfig` or environment variable `SSHPIPERD_KUBERNETES_KUBECONFIG=/path/to/kubeconfig` to specify the kubeconfig file.
+
 ### Helm
 
 [![Artifact Hub](https://img.shields.io/endpoint?url=https://artifacthub.io/badge/repository/sshpiper)](https://artifacthub.io/packages/helm/sshpiper/sshpiper)

plugin/kubernetes/kubernetes.go

@@ -33,9 +33,11 @@ type plugin struct {
 	cache     *gocache.Cache
 }
 
-func newKubernetesPlugin(allNamespaces bool) (*plugin, error) {
+func newKubernetesPlugin(allNamespaces bool, kubeConfigPath string) (*plugin, error) {
+	loader := clientcmd.NewDefaultClientConfigLoadingRules()
+	loader.ExplicitPath = kubeConfigPath
 	kubeConfig := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(
-		clientcmd.NewDefaultClientConfigLoadingRules(),
+		loader,
 		&clientcmd.ConfigOverrides{},
 	)
 

plugin/kubernetes/main.go

@@ -16,9 +16,15 @@ func main() {
 				EnvVars:  []string{"SSHPIPERD_KUBERNETES_ALL_NAMESPACES"},
 				Required: false,
 			},
+			&cli.StringFlag{
+				Name:     "kubeconfig",
+				Usage:    "Path to kubeconfig file",
+				EnvVars:  []string{"SSHPIPERD_KUBERNETES_KUBECONFIG", "KUBECONFIG"},
+				Required: false,
+			},
 		},
 		CreateConfig: func(c *cli.Context) (*libplugin.SshPiperPluginConfig, error) {
-			plugin, err := newKubernetesPlugin(c.Bool("all-namespaces"))
+			plugin, err := newKubernetesPlugin(c.Bool("all-namespaces"), c.String("kubeconfig"))
 			if err != nil {
 				return nil, err
 			}