fix: Ensure only one CheCluster is created (#1517)

* fix: Ensure only one CheCluster is created

Signed-off-by: Anatolii Bazko <abazko@redhat.com>

api/v2/checluster_webhook.go

@@ -20,6 +20,7 @@ import (
 	"github.com/eclipse-che/che-operator/pkg/common/constants"
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/json"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 
 	k8shelper "github.com/eclipse-che/che-operator/pkg/common/k8s-helper"
 	corev1 "k8s.io/api/core/v1"
@@ -43,6 +44,9 @@ var _ webhook.Validator = &CheCluster{}
 
 // ValidateCreate implements webhook.Validator so a webhook will be registered for the type
 func (r *CheCluster) ValidateCreate() error {
+	if err := ensureSingletonCheCluster(); err != nil {
+		return err
+	}
 	return validate(r)
 }
 
@@ -56,6 +60,23 @@ func (r *CheCluster) ValidateDelete() error {
 	return nil
 }
 
+func ensureSingletonCheCluster() error {
+	client := k8shelper.New().GetClient()
+	utilruntime.Must(AddToScheme(client.Scheme()))
+
+	che := &CheClusterList{}
+	err := client.List(context.TODO(), che)
+	if err != nil {
+		logger.Error(err, "Failed to list CheCluster Custom Resources.")
+	}
+
+	if len(che.Items) != 0 {
+		return fmt.Errorf("only one CheCluster is allowed")
+	}
+
+	return nil
+}
+
 func validate(checluster *CheCluster) error {
 	for _, github := range checluster.Spec.GitServices.GitHub {
 		if err := validateGitHubOAuthSecret(github, checluster.Namespace); err != nil {

pkg/common/k8s-helper/k8s_helper.go

@@ -18,6 +18,10 @@ import (
 	"io"
 	"os"
 
+	"k8s.io/apimachinery/pkg/runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	fakeclient "sigs.k8s.io/controller-runtime/pkg/client/fake"
+
 	"k8s.io/client-go/kubernetes/fake"
 
 	"github.com/sirupsen/logrus"
@@ -31,6 +35,7 @@ import (
 
 type K8sHelper struct {
 	clientset kubernetes.Interface
+	client    client.Client
 }
 
 var (
@@ -53,6 +58,10 @@ func (cl *K8sHelper) GetClientset() kubernetes.Interface {
 	return cl.clientset
 }
 
+func (cl *K8sHelper) GetClient() client.Client {
+	return cl.client
+}
+
 func (cl *K8sHelper) ExecIntoPod(
 	deploymentName string,
 	command string,
@@ -159,6 +168,7 @@ func (cl *K8sHelper) RunExec(command []string, podName, namespace string, stdin
 func initializeForTesting() *K8sHelper {
 	k8sHelper = &K8sHelper{
 		clientset: fake.NewSimpleClientset(),
+		client:    fakeclient.NewClientBuilder().Build(),
 	}
 
 	return k8sHelper
@@ -175,8 +185,14 @@ func initialize() *K8sHelper {
 		logrus.Fatalf("Failed to initialized Kubernetes client: %v", err)
 	}
 
+	client, err := client.New(cfg, client.Options{Scheme: runtime.NewScheme()})
+	if err != nil {
+		logrus.Fatalf("Failed to initialized Kubernetes client: %v", err)
+	}
+
 	k8sHelper = &K8sHelper{
 		clientset: clientSet,
+		client:    client,
 	}
 
 	return k8sHelper