Add example of how to use e2e framework with real cluster

examples/real_cluster/README.md

@@ -0,0 +1,32 @@
+# Real cluster example (including cloud provider)
+
+This package shows how the test framework can be used with a real self-managed or cloud vendor managed cluster (AKS/GKE/EKS), since one may want to launch some tests inside the cluster. This example creates a random namespace, deploys simple deployment and if done removes the namespace.
+
+To properly connect to a cloud provider cluster it is required to import for side effects one of auth module. If testing on self-managed cluster there is no need to include these dependencies.
+```go
+	_ "k8s.io/client-go/plugin/pkg/client/auth/azure" // auth for AKS clusters
+	_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"   // auth for GKE clusters
+	_ "k8s.io/client-go/plugin/pkg/client/auth/oidc"  // auth for OIDC (EKS)
+```
+
+ResolveKubeConfigFile() function is called to get kubeconfig loaded, it uses either `--kubeconfig` flag, `KUBECONFIG` env or by default ` $HOME/.kube/config` path.
+
+```go
+func TestMain(m *testing.M) {
+	testenv = env.New()
+	path := conf.ResolveKubeConfigFile()
+	cfg := envconf.NewWithKubeConfig(path)
+	testenv = env.NewWithConfig(cfg)
+```
+
+Later testing is the same as on Kind cluster.
+
+```go
+	testenv.Setup(
+		envfuncs.CreateNamespace(namespace),
+	)
+	testenv.Finish(
+		envfuncs.DeleteNamespace(namespace),
+	)
+	os.Exit(testenv.Run(m))
+```

examples/real_cluster/kind_with_config_test.go

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+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package e2e
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	appsv1 "k8s.io/api/apps/v1"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"sigs.k8s.io/e2e-framework/pkg/envconf"
+	"sigs.k8s.io/e2e-framework/pkg/features"
+)
+
+func TestRealCluster(t *testing.T) {
+	deploymentFeature := features.New("appsv1/deployment").
+		Setup(func(ctx context.Context, t *testing.T, cfg *envconf.Config) context.Context {
+			// start a deployment
+			deployment := newDeployment(cfg.Namespace(), "test-deployment", 1)
+			if err := cfg.Client().Resources().Create(ctx, deployment); err != nil {
+				t.Fatal(err)
+			}
+			time.Sleep(2 * time.Second)
+			return ctx
+		}).
+		Assess("deployment creation", func(ctx context.Context, t *testing.T, cfg *envconf.Config) context.Context {
+			var dep appsv1.Deployment
+			if err := cfg.Client().Resources().Get(ctx, "test-deployment", cfg.Namespace(), &dep); err != nil {
+				t.Fatal(err)
+			}
+			if &dep != nil {
+				t.Logf("deployment found: %s", dep.Name)
+			}
+			return context.WithValue(ctx, "test-deployment", &dep)
+		}).
+		Teardown(func(ctx context.Context, t *testing.T, cfg *envconf.Config) context.Context {
+			dep := ctx.Value("test-deployment").(*appsv1.Deployment)
+			if err := cfg.Client().Resources().Delete(ctx, dep); err != nil {
+				t.Fatal(err)
+			}
+			return ctx
+		}).Feature()
+
+	testenv.Test(t, deploymentFeature)
+}
+
+func newDeployment(namespace string, name string, replicaCount int32) *appsv1.Deployment {
+	return &appsv1.Deployment{
+		ObjectMeta: metav1.ObjectMeta{Name: name, Namespace: namespace, Labels: map[string]string{"app": "test-app"}},
+		Spec: appsv1.DeploymentSpec{
+			Replicas: &replicaCount,
+			Selector: &metav1.LabelSelector{
+				MatchLabels: map[string]string{"app": "test-app"},
+			},
+			Template: corev1.PodTemplateSpec{
+				ObjectMeta: metav1.ObjectMeta{Labels: map[string]string{"app": "test-app"}},
+				Spec:       corev1.PodSpec{Containers: []corev1.Container{{Name: "nginx", Image: "nginx"}}},
+			},
+		},
+	}
+}

examples/real_cluster/main_test.go

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+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package e2e
+
+import (
+	// If testing with a cloud vendor managed cluster uncomment one of the below dependencies to properly get authorised.
+	//_ "k8s.io/client-go/plugin/pkg/client/auth/azure" // auth for AKS clusters
+	//_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"   // auth for GKE clusters
+	//_ "k8s.io/client-go/plugin/pkg/client/auth/oidc"  // auth for OIDC
+	"os"
+	"sigs.k8s.io/e2e-framework/klient/conf"
+	"sigs.k8s.io/e2e-framework/pkg/env"
+	"sigs.k8s.io/e2e-framework/pkg/envconf"
+	"sigs.k8s.io/e2e-framework/pkg/envfuncs"
+	"testing"
+)
+
+var testenv env.Environment
+
+func TestMain(m *testing.M) {
+	testenv = env.New()
+	path := conf.ResolveKubeConfigFile()
+	cfg := envconf.NewWithKubeConfig(path)
+	testenv = env.NewWithConfig(cfg)
+	namespace := envconf.RandomName("sample-ns", 16)
+	testenv.Setup(
+		envfuncs.CreateNamespace(namespace),
+	)
+	testenv.Finish(
+		envfuncs.DeleteNamespace(namespace),
+	)
+	os.Exit(testenv.Run(m))
+}