implement e2e test lb (#815)

* implement e2e test lb
* add lb e2e test to weekly schedule
Signed-off-by: Fabian Kammel <fk@edgeless.systems>

e2e/internal/kubectl/kubectl.go

@@ -0,0 +1,40 @@
+/*
+Copyright (c) Edgeless Systems GmbH
+
+SPDX-License-Identifier: AGPL-3.0-only
+*/
+
+package kubectl
+
+import (
+	"fmt"
+	"os"
+
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/tools/clientcmd"
+)
+
+// New creates a new k8s client. The kube config file is expected to be set
+// via environment variable KUBECONFIG or located at ./constellation-admin.conf.
+func New() (*kubernetes.Clientset, error) {
+	cfgPath := ""
+	if envPath := os.Getenv("KUBECONFIG"); envPath != "" {
+		cfgPath = envPath
+		fmt.Printf("K8s config path empty. Using environment variable %s=%s.\n", "KUBECONFIG", envPath)
+	} else {
+		cfgPath = "constellation-admin.conf"
+		fmt.Printf("K8s config path empty. Assuming '%s'.\n", cfgPath)
+	}
+
+	kubeConfig, err := clientcmd.BuildConfigFromFlags("", cfgPath)
+	if err != nil {
+		return nil, err
+	}
+
+	k8sClient, err := kubernetes.NewForConfig(kubeConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	return k8sClient, nil
+}