STRUCTURE: cmd/kube-apiserver/app: stratify construction with options/config/server

cmd/kube-apiserver/app/aggregator.go

@@ -116,8 +116,8 @@ func createAggregatorConfig(
 	return aggregatorConfig, nil
 }
 
-func createAggregatorServer(aggregatorConfig *aggregatorapiserver.Config, delegateAPIServer genericapiserver.DelegationTarget, apiExtensionInformers apiextensionsinformers.SharedInformerFactory, crdAPIEnabled bool) (*aggregatorapiserver.APIAggregator, error) {
-	aggregatorServer, err := aggregatorConfig.Complete().NewWithDelegate(delegateAPIServer)
+func createAggregatorServer(aggregatorConfig aggregatorapiserver.CompletedConfig, delegateAPIServer genericapiserver.DelegationTarget, apiExtensionInformers apiextensionsinformers.SharedInformerFactory, crdAPIEnabled bool) (*aggregatorapiserver.APIAggregator, error) {
+	aggregatorServer, err := aggregatorConfig.NewWithDelegate(delegateAPIServer)
 	if err != nil {
 		return nil, err
 	}

cmd/kube-apiserver/app/config.go

@@ -0,0 +1,93 @@
+/*
+Copyright 2023 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 app
+
+import (
+	apiextensionsapiserver "k8s.io/apiextensions-apiserver/pkg/apiserver"
+	"k8s.io/apiserver/pkg/util/webhook"
+	aggregatorapiserver "k8s.io/kube-aggregator/pkg/apiserver"
+	"k8s.io/kubernetes/pkg/controlplane"
+	"k8s.io/kubernetes/pkg/controlplane/apiserver"
+)
+
+type Config struct {
+	Options completedServerRunOptions
+
+	Aggregator    *aggregatorapiserver.Config
+	ControlPlane  *controlplane.Config
+	ApiExtensions *apiextensionsapiserver.Config
+
+	ExtraConfig
+}
+
+type ExtraConfig struct {
+}
+
+type completedConfig struct {
+	Options completedServerRunOptions
+
+	Aggregator    aggregatorapiserver.CompletedConfig
+	ControlPlane  controlplane.CompletedConfig
+	ApiExtensions apiextensionsapiserver.CompletedConfig
+
+	ExtraConfig
+}
+
+type CompletedConfig struct {
+	// Embed a private pointer that cannot be instantiated outside of this package.
+	*completedConfig
+}
+
+func (c *Config) Complete() (CompletedConfig, error) {
+	return CompletedConfig{&completedConfig{
+		Options: c.Options,
+
+		Aggregator:    c.Aggregator.Complete(),
+		ControlPlane:  c.ControlPlane.Complete(),
+		ApiExtensions: c.ApiExtensions.Complete(),
+
+		ExtraConfig: c.ExtraConfig,
+	}}, nil
+}
+
+// NewConfig creates all the resources for running kube-apiserver, but runs none of them.
+func NewConfig(opts completedServerRunOptions) (*Config, error) {
+	c := &Config{
+		Options: opts,
+	}
+
+	controlPlane, serviceResolver, pluginInitializer, err := CreateKubeAPIServerConfig(opts)
+	if err != nil {
+		return nil, err
+	}
+	c.ControlPlane = controlPlane
+
+	apiExtensions, err := apiserver.CreateAPIExtensionsConfig(*controlPlane.GenericConfig, controlPlane.ExtraConfig.VersionedInformers, pluginInitializer, opts.ServerRunOptions, opts.MasterCount,
+		serviceResolver, webhook.NewDefaultAuthenticationInfoResolverWrapper(controlPlane.ExtraConfig.ProxyTransport, controlPlane.GenericConfig.EgressSelector, controlPlane.GenericConfig.LoopbackClientConfig, controlPlane.GenericConfig.TracerProvider))
+	if err != nil {
+		return nil, err
+	}
+	c.ApiExtensions = apiExtensions
+
+	aggregator, err := createAggregatorConfig(*controlPlane.GenericConfig, opts.ServerRunOptions, controlPlane.ExtraConfig.VersionedInformers, serviceResolver, controlPlane.ExtraConfig.ProxyTransport, pluginInitializer)
+	if err != nil {
+		return nil, err
+	}
+	c.Aggregator = aggregator
+
+	return c, nil
+}

cmd/kube-apiserver/app/server.go

@@ -79,7 +79,6 @@ import (
 	"k8s.io/kubernetes/pkg/api/legacyscheme"
 	"k8s.io/kubernetes/pkg/capabilities"
 	"k8s.io/kubernetes/pkg/controlplane"
-	"k8s.io/kubernetes/pkg/controlplane/apiserver"
 	"k8s.io/kubernetes/pkg/controlplane/reconcilers"
 	generatedopenapi "k8s.io/kubernetes/pkg/generated/openapi"
 	"k8s.io/kubernetes/pkg/kubeapiserver"
@@ -163,13 +162,21 @@ cluster's shared state through which all other components interact.`,
 }
 
 // Run runs the specified APIServer.  This should never exit.
-func Run(completeOptions completedServerRunOptions, stopCh <-chan struct{}) error {
+func Run(options completedServerRunOptions, stopCh <-chan struct{}) error {
 	// To help debugging, immediately log version
 	klog.Infof("Version: %+v", version.Get())
 
 	klog.InfoS("Golang settings", "GOGC", os.Getenv("GOGC"), "GOMAXPROCS", os.Getenv("GOMAXPROCS"), "GOTRACEBACK", os.Getenv("GOTRACEBACK"))
 
-	server, err := CreateServerChain(completeOptions)
+	config, err := NewConfig(options)
+	if err != nil {
+		return err
+	}
+	completed, err := config.Complete()
+	if err != nil {
+		return err
+	}
+	server, err := CreateServerChain(completed)
 	if err != nil {
 		return err
 	}
@@ -183,37 +190,21 @@ func Run(completeOptions completedServerRunOptions, stopCh <-chan struct{}) erro
 }
 
 // CreateServerChain creates the apiservers connected via delegation.
-func CreateServerChain(completedOptions completedServerRunOptions) (*aggregatorapiserver.APIAggregator, error) {
-	kubeAPIServerConfig, serviceResolver, pluginInitializer, err := CreateKubeAPIServerConfig(completedOptions)
+func CreateServerChain(config CompletedConfig) (*aggregatorapiserver.APIAggregator, error) {
+	notFoundHandler := notfoundhandler.New(config.ControlPlane.GenericConfig.Serializer, genericapifilters.NoMuxAndDiscoveryIncompleteKey)
+	apiExtensionsServer, err := config.ApiExtensions.New(genericapiserver.NewEmptyDelegateWithCustomHandler(notFoundHandler))
 	if err != nil {
 		return nil, err
 	}
+	crdAPIEnabled := config.ApiExtensions.GenericConfig.MergedResourceConfig.ResourceEnabled(apiextensionsv1.SchemeGroupVersion.WithResource("customresourcedefinitions"))
 
-	// If additional API servers are added, they should be gated.
-	apiExtensionsConfig, err := apiserver.CreateAPIExtensionsConfig(*kubeAPIServerConfig.GenericConfig, kubeAPIServerConfig.ExtraConfig.VersionedInformers, pluginInitializer, completedOptions.ServerRunOptions, completedOptions.MasterCount,
-		serviceResolver, webhook.NewDefaultAuthenticationInfoResolverWrapper(kubeAPIServerConfig.ExtraConfig.ProxyTransport, kubeAPIServerConfig.GenericConfig.EgressSelector, kubeAPIServerConfig.GenericConfig.LoopbackClientConfig, kubeAPIServerConfig.GenericConfig.TracerProvider))
-	if err != nil {
-		return nil, err
-	}
-	crdAPIEnabled := apiExtensionsConfig.GenericConfig.MergedResourceConfig.ResourceEnabled(apiextensionsv1.SchemeGroupVersion.WithResource("customresourcedefinitions"))
-
-	notFoundHandler := notfoundhandler.New(kubeAPIServerConfig.GenericConfig.Serializer, genericapifilters.NoMuxAndDiscoveryIncompleteKey)
-	apiExtensionsServer, err := apiExtensionsConfig.Complete().New(genericapiserver.NewEmptyDelegateWithCustomHandler(notFoundHandler))
-	if err != nil {
-		return nil, err
-	}
-
-	kubeAPIServer, err := kubeAPIServerConfig.Complete().New(apiExtensionsServer.GenericAPIServer)
+	kubeAPIServer, err := config.ControlPlane.New(apiExtensionsServer.GenericAPIServer)
 	if err != nil {
 		return nil, err
 	}
 
 	// aggregator comes last in the chain
-	aggregatorConfig, err := createAggregatorConfig(*kubeAPIServerConfig.GenericConfig, completedOptions.ServerRunOptions, kubeAPIServerConfig.ExtraConfig.VersionedInformers, serviceResolver, kubeAPIServerConfig.ExtraConfig.ProxyTransport, pluginInitializer)
-	if err != nil {
-		return nil, err
-	}
-	aggregatorServer, err := createAggregatorServer(aggregatorConfig, kubeAPIServer.GenericAPIServer, apiExtensionsServer.Informers, crdAPIEnabled)
+	aggregatorServer, err := createAggregatorServer(config.Aggregator, kubeAPIServer.GenericAPIServer, apiExtensionsServer.Informers, crdAPIEnabled)
 	if err != nil {
 		// we don't need special handling for innerStopCh because the aggregator server doesn't create any go routines
 		return nil, err

cmd/kube-apiserver/app/testing/testserver.go

@@ -246,7 +246,16 @@ func StartTestServer(t Logger, instanceOptions *TestServerInstanceOptions, custo
 
 	t.Logf("runtime-config=%v", completedOptions.APIEnablement.RuntimeConfig)
 	t.Logf("Starting kube-apiserver on port %d...", s.SecureServing.BindPort)
-	server, err := app.CreateServerChain(completedOptions)
+
+	config, err := app.NewConfig(completedOptions)
+	if err != nil {
+		return result, err
+	}
+	completed, err := config.Complete()
+	if err != nil {
+		return result, err
+	}
+	server, err := app.CreateServerChain(completed)
 	if err != nil {
 		return result, fmt.Errorf("failed to create server chain: %v", err)
 	}

test/integration/etcd/server.go

@@ -124,7 +124,15 @@ func StartRealAPIServerOrDie(t *testing.T, configFuncs ...func(*options.ServerRu
 		t.Fatal(err)
 	}
 
-	kubeAPIServer, err := app.CreateServerChain(completedOptions)
+	config, err := app.NewConfig(completedOptions)
+	if err != nil {
+		t.Fatal(err)
+	}
+	completed, err := config.Complete()
+	if err != nil {
+		t.Fatal(err)
+	}
+	kubeAPIServer, err := app.CreateServerChain(completed)
 	if err != nil {
 		t.Fatal(err)
 	}