controlruntime.GetConfig instead of just inClusterConfig to also cove…

…r unit tests correctly

components/odh-notebook-controller/controllers/notebook_webhook.go

@@ -37,6 +37,7 @@ import (
 	"k8s.io/client-go/rest"
 	"k8s.io/utils/pointer"
 	"sigs.k8s.io/controller-runtime/pkg/client"
+	ctrlruntime "sigs.k8s.io/controller-runtime/pkg/client/config"
 	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
 )
 
@@ -456,19 +457,23 @@ func InjectCertConfig(notebook *nbv1.Notebook, configMapName string) error {
 }
 
 func getControllerNamespace() (string, error) {
-    // Check if running inside a Kubernetes cluster
-    if _, err := rest.InClusterConfig(); err != nil {
-        return "", fmt.Errorf("not running inside a Kubernetes cluster")
-    }
-
-    // Try to get the namespace from the service account secret
-    if data, err := os.ReadFile("/var/run/secrets/kubernetes.io/serviceaccount/namespace"); err == nil {
-        if ns := string(data); len(ns) > 0 {
-            return ns, nil
-        }
-    }
-
-    return "", fmt.Errorf("unable to determine the namespace")
+	// Check if running inside a Kubernetes cluster
+	// GetConfig(): If KUBECONFIG env variable is set, it is used to create
+	// the client, else the inClusterConfig() is used.
+	// Lastly if none of them are set, it uses  $HOME/.kube/config to create the client.
+	config, err := ctrlruntime.GetConfig()
+	if err != nil {
+		return nil, fmt.Errorf("error creating the config object, not running inside a Kubernetes/Openshift Cluster %v", err)
+	}
+
+	// Try to get the namespace from the service account secret
+	if data, err := os.ReadFile("/var/run/secrets/kubernetes.io/serviceaccount/namespace"); err == nil {
+		if ns := string(data); len(ns) > 0 {
+			return ns, nil
+		}
+	}
+
+	return "", fmt.Errorf("unable to determine the namespace")
 }
 
 // SetContainerImageFromRegistry checks if there is an internal registry and takes the corresponding actions to set the container.image value.