Aggregate OpenAPI spec

cmd/kube-apiserver/app/aggregator.go

@@ -51,7 +51,6 @@ func createAggregatorConfig(kubeAPIServerConfig genericapiserver.Config, command
 
 	// the aggregator doesn't wire these up.  It just delegates them to the kubeapiserver
 	genericConfig.EnableSwaggerUI = false
-	genericConfig.OpenAPIConfig = nil
 	genericConfig.SwaggerConfig = nil
 
 	// copy the etcd options so we don't mutate originals.

staging/src/k8s.io/kube-aggregator/pkg/apiserver/apiserver.go

@@ -116,6 +116,8 @@ type APIAggregator struct {
 
 	// Information needed to determine routing for the aggregator
 	serviceResolver ServiceResolver
+
+	openAPIAggregator *openAPIAggregator
 }
 
 type completedConfig struct {
@@ -142,6 +144,11 @@ func (c *Config) SkipComplete() completedConfig {
 
 // New returns a new instance of APIAggregator from the given config.
 func (c completedConfig) NewWithDelegate(delegationTarget genericapiserver.DelegationTarget) (*APIAggregator, error) {
+	// Prevent generic API server to install OpenAPI handler. Aggregator server
+	// has its own customized OpenAPI handler.
+	openApiConfig := c.Config.GenericConfig.OpenAPIConfig
+	c.Config.GenericConfig.OpenAPIConfig = nil
+
 	genericServer, err := c.Config.GenericConfig.SkipComplete().New("kube-aggregator", delegationTarget) // completion is done in Complete, no need for a second time
 	if err != nil {
 		return nil, err
@@ -212,17 +219,29 @@ func (c completedConfig) NewWithDelegate(delegationTarget genericapiserver.Deleg
 		return nil
 	})
 
+	if openApiConfig != nil {
+		s.openAPIAggregator, err = buildAndRegisterOpenAPIAggregator(
+			s.delegateHandler,
+			s.GenericAPIServer.Handler.GoRestfulContainer.RegisteredWebServices(),
+			openApiConfig,
+			s.GenericAPIServer.Handler.NonGoRestfulMux,
+			s.contextMapper)
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	return s, nil
 }
 
 // AddAPIService adds an API service.  It is not thread-safe, so only call it on one thread at a time please.
 // It's a slow moving API, so its ok to run the controller on a single thread
-func (s *APIAggregator) AddAPIService(apiService *apiregistration.APIService) {
+func (s *APIAggregator) AddAPIService(apiService *apiregistration.APIService) error {
 	// if the proxyHandler already exists, it needs to be updated. The aggregation bits do not
 	// since they are wired against listers because they require multiple resources to respond
 	if proxyHandler, exists := s.proxyHandlers[apiService.Name]; exists {
 		proxyHandler.updateAPIService(apiService)
-		return
+		return s.openAPIAggregator.loadApiServiceSpec(proxyHandler, apiService)
 	}
 
 	proxyPath := "/apis/" + apiService.Spec.Group + "/" + apiService.Spec.Version
@@ -241,18 +260,21 @@ func (s *APIAggregator) AddAPIService(apiService *apiregistration.APIService) {
 		serviceResolver: s.serviceResolver,
 	}
 	proxyHandler.updateAPIService(apiService)
+	if err := s.openAPIAggregator.loadApiServiceSpec(proxyHandler, apiService); err != nil {
+		return err
+	}
 	s.proxyHandlers[apiService.Name] = proxyHandler
 	s.GenericAPIServer.Handler.NonGoRestfulMux.Handle(proxyPath, proxyHandler)
 	s.GenericAPIServer.Handler.NonGoRestfulMux.UnlistedHandlePrefix(proxyPath+"/", proxyHandler)
 
 	// if we're dealing with the legacy group, we're done here
 	if apiService.Name == legacyAPIServiceName {
-		return
+		return nil
 	}
 
 	// if we've already registered the path with the handler, we don't want to do it again.
 	if s.handledGroups.Has(apiService.Spec.Group) {
-		return
+		return nil
 	}
 
 	// it's time to register the group aggregation endpoint
@@ -268,6 +290,7 @@ func (s *APIAggregator) AddAPIService(apiService *apiregistration.APIService) {
 	s.GenericAPIServer.Handler.NonGoRestfulMux.Handle(groupPath, groupDiscoveryHandler)
 	s.GenericAPIServer.Handler.NonGoRestfulMux.UnlistedHandle(groupPath+"/", groupDiscoveryHandler)
 	s.handledGroups.Insert(apiService.Spec.Group)
+	return nil
 }
 
 // RemoveAPIService removes the APIService from being handled.  It is not thread-safe, so only call it on one thread at a time please.

staging/src/k8s.io/kube-aggregator/pkg/apiserver/apiservice_controller.go

@@ -39,7 +39,7 @@ import (
 )
 
 type APIHandlerManager interface {
-	AddAPIService(apiService *apiregistration.APIService)
+	AddAPIService(apiService *apiregistration.APIService) error
 	RemoveAPIService(apiServiceName string)
 }
 
@@ -102,8 +102,7 @@ func (c *APIServiceRegistrationController) sync(key string) error {
 		return nil
 	}
 
-	c.apiHandlerManager.AddAPIService(apiService)
-	return nil
+	return c.apiHandlerManager.AddAPIService(apiService)
 }
 
 func (c *APIServiceRegistrationController) Run(stopCh <-chan struct{}) {

staging/src/k8s.io/kube-aggregator/pkg/apiserver/openapi_aggregator.go

@@ -0,0 +1,270 @@
+/*
+Copyright 2017 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 (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"sort"
+	"time"
+
+	"github.com/emicklei/go-restful"
+	"github.com/go-openapi/spec"
+
+	"k8s.io/apiserver/pkg/authentication/user"
+	"k8s.io/apiserver/pkg/endpoints/request"
+	"k8s.io/kube-aggregator/pkg/apis/apiregistration"
+	"k8s.io/kube-openapi/pkg/aggregator"
+	"k8s.io/kube-openapi/pkg/builder"
+	"k8s.io/kube-openapi/pkg/common"
+	"k8s.io/kube-openapi/pkg/handler"
+)
+
+const (
+	aggregatorUser      = "system:aggregator"
+	specDownloadTimeout = 60 * time.Second
+)
+
+type openAPIAggregator struct {
+	// Map of API Services' OpenAPI specs by their name
+	openAPISpecs map[string]*openAPISpecInfo
+
+	// provided for dynamic OpenAPI spec
+	openAPIService *handler.OpenAPIService
+
+	// Aggregator's OpenAPI spec (holds apiregistration group).
+	aggregatorOpenAPISpec *spec.Swagger
+
+	// Local (in process) delegate's OpenAPI spec.
+	inProcessDelegatesOpenAPISpec *spec.Swagger
+
+	contextMapper request.RequestContextMapper
+}
+
+func buildAndRegisterOpenAPIAggregator(delegateHandler http.Handler, webServices []*restful.WebService, config *common.Config, pathHandler common.PathHandler, contextMapper request.RequestContextMapper) (s *openAPIAggregator, err error) {
+	s = &openAPIAggregator{
+		openAPISpecs:  map[string]*openAPISpecInfo{},
+		contextMapper: contextMapper,
+	}
+
+	// Get Local delegate's Spec
+	s.inProcessDelegatesOpenAPISpec, err = s.downloadOpenAPISpec(delegateHandler)
+	if err != nil {
+		return nil, err
+	}
+
+	// Build Aggregator's spec
+	s.aggregatorOpenAPISpec, err = builder.BuildOpenAPISpec(
+		webServices, config)
+	if err != nil {
+		return nil, err
+	}
+	// Remove any non-API endpoints from aggregator's spec. aggregatorOpenAPISpec
+	// is the source of truth for all non-api endpoints.
+	aggregator.FilterSpecByPaths(s.aggregatorOpenAPISpec, []string{"/apis/"})
+
+	// Build initial spec to serve.
+	specToServe, err := s.buildOpenAPISpec()
+	if err != nil {
+		return nil, err
+	}
+
+	// Install handler
+	s.openAPIService, err = handler.RegisterOpenAPIService(
+		specToServe, "/swagger.json", pathHandler)
+	if err != nil {
+		return nil, err
+	}
+
+	return s, nil
+}
+
+// openAPISpecInfo is used to store OpenAPI spec with its priority.
+// It can be used to sort specs with their priorities.
+type openAPISpecInfo struct {
+	apiService apiregistration.APIService
+	spec       *spec.Swagger
+}
+
+// byPriority can be used in sort.Sort to sort specs with their priorities.
+type byPriority struct {
+	specs           []openAPISpecInfo
+	groupPriorities map[string]int32
+}
+
+func (a byPriority) Len() int      { return len(a.specs) }
+func (a byPriority) Swap(i, j int) { a.specs[i], a.specs[j] = a.specs[j], a.specs[i] }
+func (a byPriority) Less(i, j int) bool {
+	var iPriority, jPriority int32
+	if a.specs[i].apiService.Spec.Group == a.specs[j].apiService.Spec.Group {
+		iPriority = a.specs[i].apiService.Spec.VersionPriority
+		jPriority = a.specs[i].apiService.Spec.VersionPriority
+	} else {
+		iPriority = a.groupPriorities[a.specs[i].apiService.Spec.Group]
+		jPriority = a.groupPriorities[a.specs[j].apiService.Spec.Group]
+	}
+	if iPriority != jPriority {
+		// Sort by priority, higher first
+		return iPriority > jPriority
+	}
+	// Sort by service name.
+	return a.specs[i].apiService.Name < a.specs[j].apiService.Name
+}
+
+func sortByPriority(specs []openAPISpecInfo) {
+	b := byPriority{
+		specs:           specs,
+		groupPriorities: map[string]int32{},
+	}
+	for _, spec := range specs {
+		if pr, found := b.groupPriorities[spec.apiService.Spec.Group]; !found || spec.apiService.Spec.GroupPriorityMinimum > pr {
+			b.groupPriorities[spec.apiService.Spec.Group] = spec.apiService.Spec.GroupPriorityMinimum
+		}
+	}
+	sort.Sort(b)
+}
+
+// buildOpenAPISpec aggregates all OpenAPI specs.  It is not thread-safe.
+func (s *openAPIAggregator) buildOpenAPISpec() (specToReturn *spec.Swagger, err error) {
+	specToReturn, err = aggregator.CloneSpec(s.inProcessDelegatesOpenAPISpec)
+	if err != nil {
+		return nil, err
+	}
+	if err := aggregator.MergeSpecs(specToReturn, s.aggregatorOpenAPISpec); err != nil {
+		return nil, fmt.Errorf("cannot merge local delegate spec with aggregator spec: %s", err.Error())
+	}
+	specs := []openAPISpecInfo{}
+	for _, specInfo := range s.openAPISpecs {
+		specs = append(specs, openAPISpecInfo{specInfo.apiService, specInfo.spec})
+	}
+	sortByPriority(specs)
+	for _, specInfo := range specs {
+		if err := aggregator.MergeSpecs(specToReturn, specInfo.spec); err != nil {
+			return nil, err
+		}
+	}
+	return specToReturn, nil
+}
+
+// updateOpenAPISpec aggregates all OpenAPI specs.  It is not thread-safe.
+func (s *openAPIAggregator) updateOpenAPISpec() error {
+	if s.openAPIService == nil {
+		return nil
+	}
+	specToServe, err := s.buildOpenAPISpec()
+	if err != nil {
+		return err
+	}
+	return s.openAPIService.UpdateSpec(specToServe)
+}
+
+// inMemoryResponseWriter is a http.Writer that keep the response in memory.
+type inMemoryResponseWriter struct {
+	header   http.Header
+	respCode int
+	data     []byte
+}
+
+func newInMemoryResponseWriter() *inMemoryResponseWriter {
+	return &inMemoryResponseWriter{header: http.Header{}}
+}
+
+func (r *inMemoryResponseWriter) Header() http.Header {
+	return r.header
+}
+
+func (r *inMemoryResponseWriter) WriteHeader(code int) {
+	r.respCode = code
+}
+
+func (r *inMemoryResponseWriter) Write(in []byte) (int, error) {
+	r.data = append(r.data, in...)
+	return len(in), nil
+}
+
+func (r *inMemoryResponseWriter) String() string {
+	s := fmt.Sprintf("ResponseCode: %d", r.respCode)
+	if r.data != nil {
+		s += fmt.Sprintf(", Body: %s", string(r.data))
+	}
+	if r.header != nil {
+		s += fmt.Sprintf(", Header: %s", r.header)
+	}
+	return s
+}
+
+func (s *openAPIAggregator) handlerWithUser(handler http.Handler, info user.Info) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		if ctx, ok := s.contextMapper.Get(req); ok {
+			s.contextMapper.Update(req, request.WithUser(ctx, info))
+		}
+		handler.ServeHTTP(w, req)
+	})
+}
+
+// downloadOpenAPISpec downloads openAPI spec from /swagger.json endpoint of the given handler.
+func (s *openAPIAggregator) downloadOpenAPISpec(handler http.Handler) (*spec.Swagger, error) {
+	handler = s.handlerWithUser(handler, &user.DefaultInfo{Name: aggregatorUser})
+	handler = request.WithRequestContext(handler, s.contextMapper)
+	handler = http.TimeoutHandler(handler, specDownloadTimeout, "request timed out")
+
+	req, err := http.NewRequest("GET", "/swagger.json", nil)
+	if err != nil {
+		return nil, err
+	}
+	writer := newInMemoryResponseWriter()
+	handler.ServeHTTP(writer, req)
+
+	switch writer.respCode {
+	case http.StatusOK:
+		openApiSpec := &spec.Swagger{}
+		if err := json.Unmarshal(writer.data, openApiSpec); err != nil {
+			return nil, err
+		}
+		return openApiSpec, nil
+	default:
+		return nil, fmt.Errorf("failed to retrive openAPI spec, http error: %s", writer.String())
+	}
+}
+
+// loadApiServiceSpec loads OpenAPI spec for the given API Service and then updates aggregator's spec.
+func (s *openAPIAggregator) loadApiServiceSpec(handler http.Handler, apiService *apiregistration.APIService) error {
+
+	// Ignore local services
+	if apiService.Spec.Service == nil {
+		return nil
+	}
+
+	openApiSpec, err := s.downloadOpenAPISpec(handler)
+	if err != nil {
+		return err
+	}
+	aggregator.FilterSpecByPaths(openApiSpec, []string{"/apis/" + apiService.Spec.Group + "/"})
+
+	s.openAPISpecs[apiService.Name] = &openAPISpecInfo{
+		apiService: *apiService,
+		spec:       openApiSpec,
+	}
+
+	err = s.updateOpenAPISpec()
+	if err != nil {
+		delete(s.openAPISpecs, apiService.Name)
+		return err
+	}
+	return nil
+}

staging/src/k8s.io/kube-aggregator/pkg/apiserver/openapi_aggregator_test.go

@@ -0,0 +1,68 @@
+/*
+Copyright 2017 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 (
+	"reflect"
+	"testing"
+
+	"github.com/go-openapi/spec"
+
+	"k8s.io/kube-aggregator/pkg/apis/apiregistration"
+)
+
+func newApiServiceForTest(name, group string, minGroupPriority, versionPriority int32) apiregistration.APIService {
+	r := apiregistration.APIService{}
+	r.Spec.Group = group
+	r.Spec.GroupPriorityMinimum = minGroupPriority
+	r.Spec.VersionPriority = versionPriority
+	r.Name = name
+	return r
+}
+
+func assertSortedServices(t *testing.T, actual []openAPISpecInfo, expectedNames []string) {
+	actualNames := []string{}
+	for _, a := range actual {
+		actualNames = append(actualNames, a.apiService.Name)
+	}
+	if !reflect.DeepEqual(actualNames, expectedNames) {
+		t.Errorf("Expected %s got %s.", expectedNames, actualNames)
+	}
+}
+
+func TestApiServiceSort(t *testing.T) {
+	list := []openAPISpecInfo{
+		{
+			apiService: newApiServiceForTest("FirstService", "Group1", 10, 5),
+			spec:       &spec.Swagger{},
+		},
+		{
+			apiService: newApiServiceForTest("SecondService", "Group2", 15, 3),
+			spec:       &spec.Swagger{},
+		},
+		{
+			apiService: newApiServiceForTest("FirstServiceInternal", "Group1", 16, 3),
+			spec:       &spec.Swagger{},
+		},
+		{
+			apiService: newApiServiceForTest("ThirdService", "Group3", 15, 3),
+			spec:       &spec.Swagger{},
+		},
+	}
+	sortByPriority(list)
+	assertSortedServices(t, list, []string{"FirstService", "FirstServiceInternal", "SecondService", "ThirdService"})
+}