Merge pull request kubernetes-sigs#15 from kawych/master

Add External Metrics API endpoint to custom-metrics-apiserver

Author: DirectXMan12

Diff for: glide.lock

@@ -50,6 +50,8 @@ import:
   subpackages:
   - pkg/apis/custom_metrics
   - pkg/apis/custom_metrics/install
+  - pkg/apis/external_metrics
+  - pkg/apis/external_metrics/install
 testImport:
 - package: github.com/stretchr/testify
   version: ^1.1.4

Diff for: glide.yaml

@@ -27,7 +27,8 @@ import (
 	genericapiserver "k8s.io/apiserver/pkg/server"
 
 	"github.com/kubernetes-incubator/custom-metrics-apiserver/pkg/provider"
-	"k8s.io/metrics/pkg/apis/custom_metrics/install"
+	cminstall "k8s.io/metrics/pkg/apis/custom_metrics/install"
+	eminstall "k8s.io/metrics/pkg/apis/external_metrics/install"
 )
 
 var (
@@ -38,7 +39,8 @@ var (
 )
 
 func init() {
-	install.Install(groupFactoryRegistry, registry, Scheme)
+	cminstall.Install(groupFactoryRegistry, registry, Scheme)
+	eminstall.Install(groupFactoryRegistry, registry, Scheme)
 
 	// we need to add the options to empty v1
 	// TODO fix the server code to avoid this
@@ -61,8 +63,9 @@ type Config struct {
 
 // CustomMetricsAdapterServer contains state for a Kubernetes cluster master/api server.
 type CustomMetricsAdapterServer struct {
-	GenericAPIServer *genericapiserver.GenericAPIServer
-	Provider         provider.CustomMetricsProvider
+	GenericAPIServer        *genericapiserver.GenericAPIServer
+	customMetricsProvider   provider.CustomMetricsProvider
+	externalMetricsProvider provider.ExternalMetricsProvider
 }
 
 type completedConfig struct {
@@ -80,19 +83,29 @@ func (c *Config) Complete() completedConfig {
 
 // New returns a new instance of CustomMetricsAdapterServer from the given config.
 // name is used to differentiate for logging.
-func (c completedConfig) New(name string, cmProvider provider.CustomMetricsProvider) (*CustomMetricsAdapterServer, error) {
+// Each of the arguments: customMetricsProvider, externalMetricsProvider can be set either to
+// a provider implementation, or to nil to disable one of the APIs.
+func (c completedConfig) New(name string, customMetricsProvider provider.CustomMetricsProvider, externalMetricsProvider provider.ExternalMetricsProvider) (*CustomMetricsAdapterServer, error) {
 	genericServer, err := c.CompletedConfig.New(name, genericapiserver.EmptyDelegate) // completion is done in Complete, no need for a second time
 	if err != nil {
 		return nil, err
 	}
 
 	s := &CustomMetricsAdapterServer{
-		GenericAPIServer: genericServer,
-		Provider:         cmProvider,
+		GenericAPIServer:        genericServer,
+		customMetricsProvider:   customMetricsProvider,
+		externalMetricsProvider: externalMetricsProvider,
 	}
 
-	if err := s.InstallCustomMetricsAPI(); err != nil {
-		return nil, err
+	if customMetricsProvider != nil {
+		if err := s.InstallCustomMetricsAPI(); err != nil {
+			return nil, err
+		}
+	}
+	if externalMetricsProvider != nil {
+		if err := s.InstallExternalMetricsAPI(); err != nil {
+			return nil, err
+		}
 	}
 
 	return s, nil

Diff for: pkg/apiserver/apiserver.go

@@ -60,8 +60,9 @@ func (s *CustomMetricsAdapterServer) InstallCustomMetricsAPI() error {
 
 	return nil
 }
+
 func (s *CustomMetricsAdapterServer) cmAPI(groupMeta *apimachinery.GroupMeta, groupVersion *schema.GroupVersion) *specificapi.MetricsAPIGroupVersion {
-	resourceStorage := metricstorage.NewREST(s.Provider)
+	resourceStorage := metricstorage.NewREST(s.customMetricsProvider)
 
 	return &specificapi.MetricsAPIGroupVersion{
 		DynamicStorage: resourceStorage,
@@ -84,6 +85,7 @@ func (s *CustomMetricsAdapterServer) cmAPI(groupMeta *apimachinery.GroupMeta, gr
 			OptionsExternalVersion: &schema.GroupVersion{Version: "v1"},
 		},
 
-		ResourceLister: provider.NewResourceLister(s.Provider),
+		ResourceLister: provider.NewCustomMetricResourceLister(s.customMetricsProvider),
+		Handlers:       &specificapi.CMHandlers{},
 	}
 }

Diff for: pkg/apiserver/cmapis.go

@@ -0,0 +1,91 @@
+/*
+Copyright 2018 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 apiserver
+
+import (
+	"k8s.io/apimachinery/pkg/apimachinery"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	genericapi "k8s.io/apiserver/pkg/endpoints"
+	"k8s.io/apiserver/pkg/endpoints/discovery"
+	genericapiserver "k8s.io/apiserver/pkg/server"
+
+	specificapi "github.com/kubernetes-incubator/custom-metrics-apiserver/pkg/apiserver/installer"
+	"github.com/kubernetes-incubator/custom-metrics-apiserver/pkg/provider"
+	metricstorage "github.com/kubernetes-incubator/custom-metrics-apiserver/pkg/registry/external_metrics"
+	"k8s.io/metrics/pkg/apis/external_metrics"
+)
+
+// InstallExternalMetricsAPI registers the api server in Kube Aggregator
+func (s *CustomMetricsAdapterServer) InstallExternalMetricsAPI() error {
+
+	groupMeta := registry.GroupOrDie(external_metrics.GroupName)
+
+	preferredVersionForDiscovery := metav1.GroupVersionForDiscovery{
+		GroupVersion: groupMeta.GroupVersion.String(),
+		Version:      groupMeta.GroupVersion.Version,
+	}
+	groupVersion := metav1.GroupVersionForDiscovery{
+		GroupVersion: groupMeta.GroupVersion.String(),
+		Version:      groupMeta.GroupVersion.Version,
+	}
+	apiGroup := metav1.APIGroup{
+		Name:             groupMeta.GroupVersion.Group,
+		Versions:         []metav1.GroupVersionForDiscovery{groupVersion},
+		PreferredVersion: preferredVersionForDiscovery,
+	}
+
+	emAPI := s.emAPI(groupMeta, &groupMeta.GroupVersion)
+
+	if err := emAPI.InstallREST(s.GenericAPIServer.Handler.GoRestfulContainer); err != nil {
+		return err
+	}
+
+	s.GenericAPIServer.DiscoveryGroupManager.AddGroup(apiGroup)
+	s.GenericAPIServer.Handler.GoRestfulContainer.Add(discovery.NewAPIGroupHandler(s.GenericAPIServer.Serializer, apiGroup, s.GenericAPIServer.RequestContextMapper()).WebService())
+
+	return nil
+}
+
+func (s *CustomMetricsAdapterServer) emAPI(groupMeta *apimachinery.GroupMeta, groupVersion *schema.GroupVersion) *specificapi.MetricsAPIGroupVersion {
+	resourceStorage := metricstorage.NewREST(s.externalMetricsProvider)
+
+	return &specificapi.MetricsAPIGroupVersion{
+		DynamicStorage: resourceStorage,
+		APIGroupVersion: &genericapi.APIGroupVersion{
+			Root:         genericapiserver.APIGroupPrefix,
+			GroupVersion: *groupVersion,
+
+			ParameterCodec:  metav1.ParameterCodec,
+			Serializer:      Codecs,
+			Creater:         Scheme,
+			Convertor:       Scheme,
+			UnsafeConvertor: runtime.UnsafeObjectConvertor(Scheme),
+			Copier:          Scheme,
+			Typer:           Scheme,
+			Linker:          groupMeta.SelfLinker,
+			Mapper:          groupMeta.RESTMapper,
+
+			Context:                s.GenericAPIServer.RequestContextMapper(),
+			MinRequestTimeout:      s.GenericAPIServer.MinRequestTimeout(),
+			OptionsExternalVersion: &schema.GroupVersion{Version: "v1"},
+		},
+		ResourceLister: provider.NewExternalMetricResourceLister(s.externalMetricsProvider),
+		Handlers:       &specificapi.EMHandlers{},
+	}
+}