Kubernetes Config Update: Prioritize InClusterConfig function

cmd/controller/main.go

@@ -33,6 +33,7 @@ import (
 	"agones.dev/agones/pkg/gameservers"
 	"agones.dev/agones/pkg/gameserversets"
 	"agones.dev/agones/pkg/metrics"
+	k8sconfig "agones.dev/agones/pkg/util/k8sconfig"
 	"agones.dev/agones/pkg/util/runtime"
 	"agones.dev/agones/pkg/util/signals"
 	"github.com/google/uuid"
@@ -49,7 +50,6 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/informers"
 	"k8s.io/client-go/kubernetes"
-	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/client-go/tools/leaderelection"
 	"k8s.io/client-go/tools/leaderelection/resourcelock"
 )
@@ -133,8 +133,8 @@ func main() {
 		logger.Fatal("Could not create controller from environment or flags")
 	}
 
-	// if the kubeconfig fails BuildConfigFromFlags will try in cluster config
-	clientConf, err := clientcmd.BuildConfigFromFlags("", ctlConf.KubeConfig)
+	// if the kubeconfig fails InClusterBuildConfig will try in cluster config
+	clientConf, err := k8sconfig.InClusterBuildConfig("", ctlConf.KubeConfig)
 	if err != nil {
 		logger.WithError(err).Fatal("Could not create in cluster config")
 	}

cmd/extensions/main.go

@@ -36,6 +36,7 @@ import (
 	"agones.dev/agones/pkg/metrics"
 	"agones.dev/agones/pkg/util/apiserver"
 	"agones.dev/agones/pkg/util/https"
+	"agones.dev/agones/pkg/util/k8sconfig"
 	"agones.dev/agones/pkg/util/runtime"
 	"agones.dev/agones/pkg/util/signals"
 	"agones.dev/agones/pkg/util/webhooks"
@@ -48,7 +49,6 @@ import (
 	"gopkg.in/natefinch/lumberjack.v2"
 	"k8s.io/client-go/informers"
 	"k8s.io/client-go/kubernetes"
-	"k8s.io/client-go/tools/clientcmd"
 )
 
 const (
@@ -114,8 +114,8 @@ func main() {
 	logger.WithField("version", pkg.Version).WithField("featureGates", runtime.EncodeFeatures()).
 		WithField("ctlConf", ctlConf).Info("starting extensions operator...")
 
-	// if the kubeconfig fails BuildConfigFromFlags will try in cluster config
-	clientConf, err := clientcmd.BuildConfigFromFlags("", ctlConf.KubeConfig)
+	// if the kubeconfig fails InClusterBuildConfig will try in cluster config
+	clientConf, err := k8sconfig.InClusterBuildConfig("", ctlConf.KubeConfig)
 	if err != nil {
 		logger.WithError(err).Fatal("Could not create in cluster config")
 	}

cmd/sdk-server/main.go

@@ -31,6 +31,7 @@ import (
 	sdkalpha "agones.dev/agones/pkg/sdk/alpha"
 	sdkbeta "agones.dev/agones/pkg/sdk/beta"
 	"agones.dev/agones/pkg/sdkserver"
+	k8sconfig "agones.dev/agones/pkg/util/k8sconfig"
 	"agones.dev/agones/pkg/util/runtime"
 	"agones.dev/agones/pkg/util/signals"
 	gwruntime "github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
@@ -42,7 +43,6 @@ import (
 	"google.golang.org/grpc/credentials/insecure"
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/rest"
-	"k8s.io/client-go/tools/clientcmd"
 )
 
 const (
@@ -119,8 +119,8 @@ func main() {
 		}
 	default:
 		var config *rest.Config
-		// if the kubeconfig fails BuildConfigFromFlags will try in cluster config
-		config, err := clientcmd.BuildConfigFromFlags("", ctlConf.KubeConfig)
+		// if the kubeconfig fails InClusterBuildConfig will try in cluster config
+		config, err := k8sconfig.InClusterBuildConfig("", ctlConf.KubeConfig)
 		if err != nil {
 			logger.WithError(err).Fatal("Could not create in cluster config")
 		}

pkg/util/k8sconfig/k8s_client_config.go

@@ -0,0 +1,33 @@
+// Copyright 2024 Google LLC All Rights Reserved.
+//
+// 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 k8sconfig helps to build kubernetes configurations.
+package k8sconfig
+
+import (
+	restclient "k8s.io/client-go/rest"
+	clientcmd "k8s.io/client-go/tools/clientcmd"
+	"k8s.io/klog"
+)
+
+// InClusterBuildConfig is a helper function that builds configs by trying the InClusterConfig().
+// If InClusterConfig is unsuccessful, it falls back to BuildConfigFromFlags.
+func InClusterBuildConfig(masterURL, kubeconfigPath string) (*restclient.Config, error) {
+	kubeconfig, err := restclient.InClusterConfig()
+	if err == nil {
+		return kubeconfig, nil
+	}
+	klog.Warning("error creating inClusterConfig, trying BuildConfigFromFlags()", err)
+	return clientcmd.BuildConfigFromFlags(masterURL, kubeconfigPath)
+}

test/e2e/framework/framework.go

@@ -34,6 +34,7 @@ import (
 	allocationv1 "agones.dev/agones/pkg/apis/allocation/v1"
 	autoscaling "agones.dev/agones/pkg/apis/autoscaling/v1"
 	"agones.dev/agones/pkg/client/clientset/versioned"
+	k8sconfig "agones.dev/agones/pkg/util/k8sconfig"
 	"agones.dev/agones/pkg/util/runtime"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -53,7 +54,6 @@ import (
 
 	// required to use gcloud login see: https://github.com/kubernetes/client-go/issues/242
 	_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
-	"k8s.io/client-go/tools/clientcmd"
 )
 
 // special labels that can be put on pods to trigger automatic cleanup.
@@ -81,7 +81,7 @@ type Framework struct {
 }
 
 func newFramework(kubeconfig string, qps float32, burst int) (*Framework, error) {
-	config, err := clientcmd.BuildConfigFromFlags("", kubeconfig)
+	config, err := k8sconfig.InClusterBuildConfig("", kubeconfig)
 	if err != nil {
 		return nil, errors.Wrap(err, "build config from flags failed")
 	}

test/eviction/evictpod.go

@@ -22,10 +22,10 @@ import (
 	"log"
 	"path/filepath"
 
+	k8sconfig "agones.dev/agones/pkg/util/k8sconfig"
 	policy "k8s.io/api/policy/v1"
 	meta_v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/kubernetes"
-	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/client-go/util/homedir"
 )
 
@@ -50,7 +50,7 @@ func main() {
 		log.Fatal("--pod must be non-empty")
 	}
 
-	config, err := clientcmd.BuildConfigFromFlags("", *kubeconfig)
+	config, err := k8sconfig.InClusterBuildConfig("", *kubeconfig)
 	if err != nil {
 		log.Fatalf("Could not build config: %v", err)
 	}