Create new kubeconfig for SupportBundleClient (#6840)

Fixes: #6687

* Create a new kubeconfig for local support bundle requests to avoid errors caused
by the absence of this file.
* Refactored ResolveKubeconfig, detailed error messages are returned, differentiating
between kubeconfig file errors and InClusterConfig errors.

Signed-off-by: Shuyang Xin <[email protected]>

pkg/antctl/raw/supportbundle/command.go

@@ -120,21 +120,18 @@ func init() {
 	}
 }
 
-var getSupportBundleClient func(cmd *cobra.Command) (systemclientset.SupportBundleInterface, error) = setupSupportBundleClient
+var getSupportBundleClient func() (systemclientset.SupportBundleInterface, error) = setupSupportBundleClient
 
-func setupSupportBundleClient(cmd *cobra.Command) (systemclientset.SupportBundleInterface, error) {
-	kubeconfig, err := raw.ResolveKubeconfig(cmd)
-	if err != nil {
-		return nil, err
-	}
+func setupSupportBundleClient() (systemclientset.SupportBundleInterface, error) {
+	kubeconfig := &rest.Config{}
 	raw.SetupLocalKubeconfig(kubeconfig)
 	client, err := systemclientset.NewForConfig(kubeconfig)
 	return client.SupportBundles(), err
 }
 
 func localSupportBundleRequest(cmd *cobra.Command, mode string, writer io.Writer) error {
 	ctx := cmd.Context()
-	client, err := getSupportBundleClient(cmd)
+	client, err := getSupportBundleClient()
 	if err != nil {
 		return fmt.Errorf("error when creating system client: %w", err)
 	}

pkg/antctl/raw/supportbundle/command_test.go

@@ -136,7 +136,7 @@ func createFakeSupportBundleClient() systemclientset.SupportBundleInterface {
 }
 
 func TestLocalSupportBundleRequest(t *testing.T) {
-	getSupportBundleClient = func(cmd *cobra.Command) (systemclientset.SupportBundleInterface, error) {
+	getSupportBundleClient = func() (systemclientset.SupportBundleInterface, error) {
 		return createFakeSupportBundleClient(), nil
 	}
 	defer func() {

pkg/antctl/runtime/runtime.go

@@ -15,6 +15,7 @@
 package runtime
 
 import (
+	"fmt"
 	"os"
 	"strings"
 
@@ -39,18 +40,37 @@ var (
 )
 
 func ResolveKubeconfig(path string) (*rest.Config, error) {
-	var err error
-	if len(path) == 0 {
-		var hasIt bool
-		path, hasIt = os.LookupEnv("KUBECONFIG")
-		if !hasIt || len(strings.TrimSpace(path)) == 0 {
+	withExplicitPath := path != ""
+	if !withExplicitPath {
+		path = strings.TrimSpace(os.Getenv("KUBECONFIG"))
+		if path == "" {
 			path = clientcmd.RecommendedHomeFile
 		}
 	}
-	if _, err = os.Stat(path); path == clientcmd.RecommendedHomeFile && os.IsNotExist(err) {
-		return rest.InClusterConfig()
+	if _, err := os.Stat(path); err != nil {
+		if !os.IsNotExist(err) {
+			return nil, err
+		}
+		if withExplicitPath {
+			return nil, fmt.Errorf("failed to resolve kubeconfig: kubeconfig file does not exist at path '%s'", path)
+		}
+		config, inClusterErr := rest.InClusterConfig()
+		if inClusterErr == nil {
+			return config, nil
+		}
+		return nil, fmt.Errorf(
+			"failed to resolve kubeconfig: neither a valid kubeconfig file was found at '%s', nor could InClusterConfig be used: %w",
+			path, inClusterErr,
+		)
+	}
+
+	config, err := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(
+		&clientcmd.ClientConfigLoadingRules{ExplicitPath: path},
+		&clientcmd.ConfigOverrides{}).ClientConfig()
+	if err != nil {
+		return nil, fmt.Errorf("failed to build kubeconfig from file at path '%s': %w", path, err)
 	}
-	return clientcmd.BuildConfigFromFlags("", path)
+	return config, nil
 }
 
 func init() {