Aggregate OpenAPI specs

cmd/kube-apiserver/app/aggregator.go

@@ -50,7 +50,6 @@ 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/apiserver/pkg/server/genericapiserver.go

@@ -28,6 +28,7 @@ import (
 	"github.com/emicklei/go-restful-swagger12"
 	"github.com/golang/glog"
 
+	"github.com/go-openapi/spec"
 	"k8s.io/apimachinery/pkg/apimachinery"
 	"k8s.io/apimachinery/pkg/apimachinery/registered"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -43,6 +44,7 @@ import (
 	apirequest "k8s.io/apiserver/pkg/endpoints/request"
 	"k8s.io/apiserver/pkg/registry/rest"
 	"k8s.io/apiserver/pkg/server/healthz"
+	"k8s.io/apiserver/pkg/server/openapi"
 	"k8s.io/apiserver/pkg/server/routes"
 	restclient "k8s.io/client-go/rest"
 )
@@ -130,6 +132,9 @@ type GenericAPIServer struct {
 	swaggerConfig *swagger.Config
 	openAPIConfig *openapicommon.Config
 
+	// Enables updating OpenAPI spec using update method.
+	OpenAPIService *openapi.OpenAPIService
+
 	// PostStartHooks are each called after the server has started listening, in a separate go func for each
 	// with no guarantee of ordering between them.  The map key is a name used for error reporting.
 	// It may kill the process with a panic if it wishes to by returning an error.
@@ -165,6 +170,9 @@ type DelegationTarget interface {
 
 	// ListedPaths returns the paths for supporting an index
 	ListedPaths() []string
+
+	// OpenAPISpec returns the OpenAPI spec of the delegation target if exists, nil otherwise.
+	OpenAPISpec() *spec.Swagger
 }
 
 func (s *GenericAPIServer) UnprotectedHandler() http.Handler {
@@ -180,6 +188,9 @@ func (s *GenericAPIServer) HealthzChecks() []healthz.HealthzChecker {
 func (s *GenericAPIServer) ListedPaths() []string {
 	return s.listedPathProvider.ListedPaths()
 }
+func (s *GenericAPIServer) OpenAPISpec() *spec.Swagger {
+	return s.OpenAPIService.GetSpec()
+}
 
 var EmptyDelegate = emptyDelegate{
 	requestContextMapper: apirequest.NewRequestContextMapper(),
@@ -204,6 +215,9 @@ func (s emptyDelegate) ListedPaths() []string {
 func (s emptyDelegate) RequestContextMapper() apirequest.RequestContextMapper {
 	return s.requestContextMapper
 }
+func (s emptyDelegate) OpenAPISpec() *spec.Swagger {
+	return nil
+}
 
 func init() {
 	// Send correct mime type for .svg files.
@@ -233,17 +247,22 @@ func (s *GenericAPIServer) PrepareRun() preparedGenericAPIServer {
 	if s.swaggerConfig != nil {
 		routes.Swagger{Config: s.swaggerConfig}.Install(s.Handler.GoRestfulContainer)
 	}
-	if s.openAPIConfig != nil {
+	s.PrepareOpenAPIService()
-		routes.OpenAPI{
-			Config: s.openAPIConfig,
-		}.Install(s.Handler.GoRestfulContainer, s.Handler.NonGoRestfulMux)
-	}
 
 	s.installHealthz()
 
 	return preparedGenericAPIServer{s}
 }
 
+// PrepareOpenAPIService installs OpenAPI handler if it does not exists.
+func (s *GenericAPIServer) PrepareOpenAPIService() {
+	if s.openAPIConfig != nil && s.OpenAPIService == nil {
+		s.OpenAPIService = routes.OpenAPI{
+			Config: s.openAPIConfig,
+		}.Install(s.Handler.GoRestfulContainer, s.Handler.NonGoRestfulMux)
+	}
+}
+
 // Run spawns the secure http server. It only returns if stopCh is closed
 // or the secure port cannot be listened on initially.
 func (s preparedGenericAPIServer) Run(stopCh <-chan struct{}) error {

staging/src/k8s.io/apiserver/pkg/server/openapi/openapi_aggregator.go

@@ -0,0 +1,482 @@
+/*
+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 openapi
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/go-openapi/spec"
+
+	"k8s.io/apimachinery/pkg/conversion"
+	"k8s.io/apiserver/pkg/util/trie"
+)
+
+const (
+	DEFINITION_PREFIX = "#/definitions/"
+)
+
+var cloner = conversion.NewCloner()
+
+// Run a walkRefCallback method on all references of an OpenAPI spec
+type walkAllRefs struct {
+	// walkRefCallback will be called on each reference and the return value
+	// will replace that reference. This will allow the callers to change
+	// all/some references of an spec (e.g. useful in renaming definitions).
+	walkRefCallback func(ref spec.Ref) spec.Ref
+
+	// The spec to walk through.
+	root *spec.Swagger
+}
+
+func newWalkAllRefs(walkRef func(ref spec.Ref) spec.Ref, sp *spec.Swagger) *walkAllRefs {
+	return &walkAllRefs{
+		walkRefCallback: walkRef,
+		root:            sp,
+	}
+}
+
+func (s *walkAllRefs) walkRef(ref spec.Ref) spec.Ref {
+	if ref.String() != "" {
+		refStr := ref.String()
+		// References that start with #/definitions/ has a definition
+		// inside the same spec file. If that is the case, walk through
+		// those definitions too.
+		// We do not support external references yet.
+		if strings.HasPrefix(refStr, DEFINITION_PREFIX) {
+			def := s.root.Definitions[refStr[len(DEFINITION_PREFIX):]]
+			s.walkSchema(&def)
+		}
+	}
+	return s.walkRefCallback(ref)
+}
+
+func (s *walkAllRefs) walkSchema(schema *spec.Schema) {
+	if schema == nil {
+		return
+	}
+	schema.Ref = s.walkRef(schema.Ref)
+	for _, v := range schema.Definitions {
+		s.walkSchema(&v)
+	}
+	for _, v := range schema.Properties {
+		s.walkSchema(&v)
+	}
+	for _, v := range schema.PatternProperties {
+		s.walkSchema(&v)
+	}
+	for _, v := range schema.AllOf {
+		s.walkSchema(&v)
+	}
+	for _, v := range schema.AnyOf {
+		s.walkSchema(&v)
+	}
+	for _, v := range schema.OneOf {
+		s.walkSchema(&v)
+	}
+	if schema.Not != nil {
+		s.walkSchema(schema.Not)
+	}
+	if schema.AdditionalProperties != nil && schema.AdditionalProperties.Schema != nil {
+		s.walkSchema(schema.AdditionalProperties.Schema)
+	}
+	if schema.AdditionalItems != nil && schema.AdditionalItems.Schema != nil {
+		s.walkSchema(schema.AdditionalItems.Schema)
+	}
+	if schema.Items != nil {
+		if schema.Items.Schema != nil {
+			s.walkSchema(schema.Items.Schema)
+		}
+		for _, v := range schema.Items.Schemas {
+			s.walkSchema(&v)
+		}
+	}
+}
+
+func (s *walkAllRefs) walkParams(params []spec.Parameter) {
+	if params == nil {
+		return
+	}
+	for _, param := range params {
+		param.Ref = s.walkRef(param.Ref)
+		s.walkSchema(param.Schema)
+		if param.Items != nil {
+			param.Items.Ref = s.walkRef(param.Items.Ref)
+		}
+	}
+}
+
+func (s *walkAllRefs) walkResponse(resp *spec.Response) {
+	if resp == nil {
+		return
+	}
+	resp.Ref = s.walkRef(resp.Ref)
+	s.walkSchema(resp.Schema)
+}
+
+func (s *walkAllRefs) walkOperation(op *spec.Operation) {
+	if op == nil {
+		return
+	}
+	s.walkParams(op.Parameters)
+	if op.Responses == nil {
+		return
+	}
+	s.walkResponse(op.Responses.Default)
+	for _, r := range op.Responses.StatusCodeResponses {
+		s.walkResponse(&r)
+	}
+}
+
+func (s *walkAllRefs) Start() {
+	for _, pathItem := range s.root.Paths.Paths {
+		s.walkParams(pathItem.Parameters)
+		s.walkOperation(pathItem.Delete)
+		s.walkOperation(pathItem.Get)
+		s.walkOperation(pathItem.Head)
+		s.walkOperation(pathItem.Options)
+		s.walkOperation(pathItem.Patch)
+		s.walkOperation(pathItem.Post)
+		s.walkOperation(pathItem.Put)
+	}
+}
+
+// FilterSpecByPaths remove unnecessary paths and unused definitions.
+func FilterSpecByPaths(sp *spec.Swagger, keepPathPrefixes []string) {
+	// First remove unwanted paths
+	prefixes := trie.New(keepPathPrefixes)
+	orgPaths := sp.Paths
+	if orgPaths == nil {
+		return
+	}
+	sp.Paths = &spec.Paths{
+		VendorExtensible: orgPaths.VendorExtensible,
+		Paths:            map[string]spec.PathItem{},
+	}
+	for path, pathItem := range orgPaths.Paths {
+		if !prefixes.HasPrefix(path) {
+			continue
+		}
+		sp.Paths.Paths[path] = pathItem
+	}
+
+	// Walk all references to find all definition references.
+	usedDefinitions := map[string]bool{}
+
+	newWalkAllRefs(func(ref spec.Ref) spec.Ref {
+		if ref.String() != "" {
+			refStr := ref.String()
+			if strings.HasPrefix(refStr, DEFINITION_PREFIX) {
+				usedDefinitions[refStr[len(DEFINITION_PREFIX):]] = true
+			}
+		}
+		return ref
+	}, sp).Start()
+
+	// Remove unused definitions
+	orgDefinitions := sp.Definitions
+	sp.Definitions = spec.Definitions{}
+	for k, v := range orgDefinitions {
+		if usedDefinitions[k] {
+			sp.Definitions[k] = v
+		}
+	}
+}
+
+func equalSchemaMap(s1, s2 map[string]spec.Schema) bool {
+	if len(s1) != len(s2) {
+		return false
+	}
+	for k, v := range s1 {
+		v2, found := s2[k]
+		if !found {
+			return false
+		}
+		if !EqualSchema(&v, &v2) {
+			return false
+		}
+	}
+	return true
+}
+
+func equalSchemaArray(s1, s2 []spec.Schema) bool {
+	if s1 == nil || s2 == nil {
+		return s1 == nil && s2 == nil
+	}
+	if len(s1) != len(s2) {
+		return false
+	}
+	for _, v1 := range s1 {
+		found := false
+		for _, v2 := range s2 {
+			if EqualSchema(&v1, &v2) {
+				found = true
+				break
+			}
+		}
+		if !found {
+			return false
+		}
+	}
+	for _, v2 := range s2 {
+		found := false
+		for _, v1 := range s1 {
+			if EqualSchema(&v1, &v2) {
+				found = true
+				break
+			}
+		}
+		if !found {
+			return false
+		}
+	}
+	return true
+}
+
+func equalSchemaOrBool(s1, s2 *spec.SchemaOrBool) bool {
+	if s1 == nil || s2 == nil {
+		return s1 == s2
+	}
+	if s1.Allows != s2.Allows {
+		return false
+	}
+	if !EqualSchema(s1.Schema, s2.Schema) {
+		return false
+	}
+	return true
+}
+
+func equalSchemaOrArray(s1, s2 *spec.SchemaOrArray) bool {
+	if s1 == nil || s2 == nil {
+		return s1 == s2
+	}
+	if !EqualSchema(s1.Schema, s2.Schema) {
+		return false
+	}
+	if !equalSchemaArray(s1.Schemas, s2.Schemas) {
+		return false
+	}
+	return true
+}
+
+func equalStringArray(s1, s2 []string) bool {
+	if len(s1) != len(s2) {
+		return false
+	}
+	for _, v1 := range s1 {
+		found := false
+		for _, v2 := range s2 {
+			if v1 == v2 {
+				found = true
+				break
+			}
+		}
+		if !found {
+			return false
+		}
+	}
+	for _, v2 := range s2 {
+		found := false
+		for _, v1 := range s1 {
+			if v1 == v2 {
+				found = true
+				break
+			}
+		}
+		if !found {
+			return false
+		}
+	}
+	return true
+}
+
+func equalFloatPointer(s1, s2 *float64) bool {
+	if s1 == nil || s2 == nil {
+		return s1 == s2
+	}
+	return *s1 == *s2
+}
+
+func equalIntPointer(s1, s2 *int64) bool {
+	if s1 == nil || s2 == nil {
+		return s1 == s2
+	}
+	return *s1 == *s2
+}
+
+// EqualSchema returns true if models have the same properties and references
+// even if they have different documentation.
+func EqualSchema(s1, s2 *spec.Schema) bool {
+	if s1 == nil || s2 == nil {
+		return s1 == s2
+	}
+	if s1.Ref.String() != s2.Ref.String() {
+		return false
+	}
+	if !equalSchemaMap(s1.Definitions, s2.Definitions) {
+		return false
+	}
+	if !equalSchemaMap(s1.Properties, s2.Properties) {
+		fmt.Println("Not equal props")
+		return false
+	}
+	if !equalSchemaMap(s1.PatternProperties, s2.PatternProperties) {
+		return false
+	}
+	if !equalSchemaArray(s1.AllOf, s2.AllOf) {
+		return false
+	}
+	if !equalSchemaArray(s1.AnyOf, s2.AnyOf) {
+		return false
+	}
+	if !equalSchemaArray(s1.OneOf, s2.OneOf) {
+		return false
+	}
+	if !EqualSchema(s1.Not, s2.Not) {
+		return false
+	}
+	if !equalSchemaOrBool(s1.AdditionalProperties, s2.AdditionalProperties) {
+		return false
+	}
+	if !equalSchemaOrBool(s1.AdditionalItems, s2.AdditionalItems) {
+		return false
+	}
+	if !equalSchemaOrArray(s1.Items, s2.Items) {
+		return false
+	}
+	if !equalStringArray(s1.Type, s2.Type) {
+		return false
+	}
+	if s1.Format != s2.Format {
+		return false
+	}
+	if !equalFloatPointer(s1.Minimum, s2.Minimum) {
+		return false
+	}
+	if !equalFloatPointer(s1.Maximum, s2.Maximum) {
+		return false
+	}
+	if s1.ExclusiveMaximum != s2.ExclusiveMaximum {
+		return false
+	}
+	if s1.ExclusiveMinimum != s2.ExclusiveMinimum {
+		return false
+	}
+	if !equalFloatPointer(s1.MultipleOf, s2.MultipleOf) {
+		return false
+	}
+	if !equalIntPointer(s1.MaxLength, s2.MaxLength) {
+		return false
+	}
+	if !equalIntPointer(s1.MinLength, s2.MinLength) {
+		return false
+	}
+	if !equalIntPointer(s1.MaxItems, s2.MaxItems) {
+		return false
+	}
+	if !equalIntPointer(s1.MinItems, s2.MinItems) {
+		return false
+	}
+	if s1.Pattern != s2.Pattern {
+		return false
+	}
+	if s1.UniqueItems != s2.UniqueItems {
+		return false
+	}
+	if !equalIntPointer(s1.MaxProperties, s2.MaxProperties) {
+		return false
+	}
+	if !equalIntPointer(s1.MinProperties, s2.MinProperties) {
+		return false
+	}
+	if !equalStringArray(s1.Required, s2.Required) {
+		return false
+	}
+	return len(s1.Enum) == 0 && len(s2.Enum) == 0 && len(s1.Dependencies) == 0 && len(s2.Dependencies) == 0
+}
+
+func renameDefinition(s *spec.Swagger, old, new string) {
+	old_ref := DEFINITION_PREFIX + old
+	new_ref := DEFINITION_PREFIX + new
+	newWalkAllRefs(func(ref spec.Ref) spec.Ref {
+		if ref.String() == old_ref {
+			return spec.MustCreateRef(new_ref)
+		}
+		return ref
+	}, s).Start()
+	s.Definitions[new] = s.Definitions[old]
+	delete(s.Definitions, old)
+}
+
+// Copy paths and definitions from source to dest, rename definitions if needed.
+// dest will be mutated, and source will not be changed.
+func MergeSpecs(dest, source *spec.Swagger) error {
+	source, err := CloneSpec(source)
+	if err != nil {
+		return err
+	}
+	for k, v := range source.Paths.Paths {
+		if _, found := dest.Paths.Paths[k]; found {
+			return fmt.Errorf("Unable to merge: Duplicated path %s", k)
+		}
+		dest.Paths.Paths[k] = v
+	}
+	usedNames := map[string]bool{}
+	for k := range dest.Definitions {
+		usedNames[k] = true
+	}
+	type Rename struct {
+		from, to string
+	}
+	renames := []Rename{}
+	for k, v := range source.Definitions {
+		v2, found := dest.Definitions[k]
+		if found || usedNames[k] {
+			if found && EqualSchema(&v, &v2) {
+				continue
+			}
+			i := 2
+			newName := fmt.Sprintf("%s_v%d", k, i)
+			for usedNames[newName] {
+				i += 1
+				newName = fmt.Sprintf("%s_v%d", k, i)
+			}
+			renames = append(renames, Rename{from: k, to: newName})
+			usedNames[newName] = true
+		} else {
+			usedNames[k] = true
+		}
+	}
+	for _, r := range renames {
+		renameDefinition(source, r.from, r.to)
+	}
+	for k, v := range source.Definitions {
+		if _, found := dest.Definitions[k]; !found {
+			dest.Definitions[k] = v
+		}
+	}
+	return nil
+}
+
+// Clone OpenAPI spec
+func CloneSpec(source *spec.Swagger) (*spec.Swagger, error) {
+	if ret, err := cloner.DeepCopy(source); err != nil {
+		return nil, err
+	} else {
+		return ret.(*spec.Swagger), nil
+	}
+}

staging/src/k8s.io/apiserver/pkg/server/openapi/openapi_aggregator_test.go

@@ -0,0 +1,520 @@
+/*
+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 openapi
+
+import (
+	"testing"
+
+	"github.com/ghodss/yaml"
+	"github.com/go-openapi/spec"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFilterSpecs(t *testing.T) {
+	var spec1, spec1_filtered *spec.Swagger
+	yaml.Unmarshal([]byte(`
+swagger: "2.0"
+paths:
+  /test:
+    post:
+      tags:
+      - "test"
+      summary: "Test API"
+      operationId: "addTest"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test"
+      responses:
+        405:
+          description: "Invalid input"
+          $ref: "#/definitions/InvalidInput"
+  /othertest:
+    post:
+      tags:
+      - "test2"
+      summary: "Test2 API"
+      operationId: "addTest2"
+      consumes:
+      - "application/json"
+      produces:
+      - "application/xml"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test2 object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test2"
+definitions:
+  Test:
+    type: "object"
+    properties:
+      id:
+        type: "integer"
+        format: "int64"
+      status:
+        type: "string"
+        description: "Status"
+  InvalidInput:
+    type: "string"
+    format: "string"
+  Test2:
+    type: "object"
+    properties:
+      other:
+        $ref: "#/definitions/Other"
+  Other:
+    type: "string"
+`), &spec1)
+	yaml.Unmarshal([]byte(`
+swagger: "2.0"
+paths:
+  /test:
+    post:
+      tags:
+      - "test"
+      summary: "Test API"
+      operationId: "addTest"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test"
+      responses:
+        405:
+          description: "Invalid input"
+          $ref: "#/definitions/InvalidInput"
+definitions:
+  Test:
+    type: "object"
+    properties:
+      id:
+        type: "integer"
+        format: "int64"
+      status:
+        type: "string"
+        description: "Status"
+  InvalidInput:
+    type: "string"
+    format: "string"
+`), &spec1_filtered)
+	assert := assert.New(t)
+	FilterSpecByPaths(spec1, []string{"/test"})
+	assert.Equal(spec1_filtered, spec1)
+}
+
+func TestMergeSpecsSimple(t *testing.T) {
+	var spec1, spec2, expected *spec.Swagger
+	yaml.Unmarshal([]byte(`
+swagger: "2.0"
+paths:
+  /test:
+    post:
+      tags:
+      - "test"
+      summary: "Test API"
+      operationId: "addTest"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test"
+      responses:
+        405:
+          description: "Invalid input"
+          $ref: "#/definitions/InvalidInput"
+definitions:
+  Test:
+    type: "object"
+    properties:
+      id:
+        type: "integer"
+        format: "int64"
+      status:
+        type: "string"
+        description: "Status"
+  InvalidInput:
+    type: "string"
+    format: "string"
+`), &spec1)
+	yaml.Unmarshal([]byte(`
+swagger: "2.0"
+paths:
+  /othertest:
+    post:
+      tags:
+      - "test2"
+      summary: "Test2 API"
+      operationId: "addTest2"
+      consumes:
+      - "application/json"
+      produces:
+      - "application/xml"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test2 object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test2"
+definitions:
+  Test2:
+    type: "object"
+    properties:
+      other:
+        $ref: "#/definitions/Other"
+  Other:
+    type: "string"
+`), &spec2)
+	yaml.Unmarshal([]byte(`
+swagger: "2.0"
+paths:
+  /test:
+    post:
+      tags:
+      - "test"
+      summary: "Test API"
+      operationId: "addTest"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test"
+      responses:
+        405:
+          description: "Invalid input"
+          $ref: "#/definitions/InvalidInput"
+  /othertest:
+    post:
+      tags:
+      - "test2"
+      summary: "Test2 API"
+      operationId: "addTest2"
+      consumes:
+      - "application/json"
+      produces:
+      - "application/xml"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test2 object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test2"
+definitions:
+  Test:
+    type: "object"
+    properties:
+      id:
+        type: "integer"
+        format: "int64"
+      status:
+        type: "string"
+        description: "Status"
+  InvalidInput:
+    type: "string"
+    format: "string"
+  Test2:
+    type: "object"
+    properties:
+      other:
+        $ref: "#/definitions/Other"
+  Other:
+    type: "string"
+`), &expected)
+	assert := assert.New(t)
+	if !assert.NoError(MergeSpecs(spec1, spec2)) {
+		return
+	}
+	assert.Equal(expected, spec1)
+}
+
+func TestMergeSpecsReuseModel(t *testing.T) {
+	var spec1, spec2, expected *spec.Swagger
+	yaml.Unmarshal([]byte(`
+swagger: "2.0"
+paths:
+  /test:
+    post:
+      tags:
+      - "test"
+      summary: "Test API"
+      operationId: "addTest"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test"
+      responses:
+        405:
+          description: "Invalid input"
+          $ref: "#/definitions/InvalidInput"
+definitions:
+  Test:
+    type: "object"
+    properties:
+      id:
+        type: "integer"
+        format: "int64"
+      status:
+        type: "string"
+        description: "Status"
+  InvalidInput:
+    type: "string"
+    format: "string"
+`), &spec1)
+	yaml.Unmarshal([]byte(`
+swagger: "2.0"
+paths:
+  /othertest:
+    post:
+      tags:
+      - "test2"
+      summary: "Test2 API"
+      operationId: "addTest2"
+      consumes:
+      - "application/json"
+      produces:
+      - "application/xml"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test2 object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test"
+definitions:
+  Test:
+    description: "This Test has a description"
+    type: "object"
+    properties:
+      id:
+        type: "integer"
+        format: "int64"
+      status:
+        type: "string"
+        description: "This status has another description"
+  InvalidInput:
+    type: "string"
+    format: "string"
+`), &spec2)
+	yaml.Unmarshal([]byte(`
+swagger: "2.0"
+paths:
+  /test:
+    post:
+      tags:
+      - "test"
+      summary: "Test API"
+      operationId: "addTest"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test"
+      responses:
+        405:
+          description: "Invalid input"
+          $ref: "#/definitions/InvalidInput"
+  /othertest:
+    post:
+      tags:
+      - "test2"
+      summary: "Test2 API"
+      operationId: "addTest2"
+      consumes:
+      - "application/json"
+      produces:
+      - "application/xml"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test2 object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test"
+definitions:
+  Test:
+    type: "object"
+    properties:
+      id:
+        type: "integer"
+        format: "int64"
+      status:
+        type: "string"
+        description: "Status"
+  InvalidInput:
+    type: "string"
+    format: "string"
+`), &expected)
+	assert := assert.New(t)
+	if !assert.NoError(MergeSpecs(spec1, spec2)) {
+		return
+	}
+	assert.Equal(expected, spec1)
+}
+
+func TestMergeSpecsRenameModel(t *testing.T) {
+	var spec1, spec2, expected *spec.Swagger
+	yaml.Unmarshal([]byte(`
+swagger: "2.0"
+paths:
+  /test:
+    post:
+      tags:
+      - "test"
+      summary: "Test API"
+      operationId: "addTest"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test"
+      responses:
+        405:
+          description: "Invalid input"
+          $ref: "#/definitions/InvalidInput"
+definitions:
+  Test:
+    type: "object"
+    properties:
+      id:
+        type: "integer"
+        format: "int64"
+      status:
+        type: "string"
+        description: "Status"
+  InvalidInput:
+    type: "string"
+    format: "string"
+`), &spec1)
+	yaml.Unmarshal([]byte(`
+swagger: "2.0"
+paths:
+  /othertest:
+    post:
+      tags:
+      - "test2"
+      summary: "Test2 API"
+      operationId: "addTest2"
+      consumes:
+      - "application/json"
+      produces:
+      - "application/xml"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test2 object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test"
+definitions:
+  Test:
+    description: "This Test has a description"
+    type: "object"
+    properties:
+      id:
+        type: "integer"
+        format: "int64"
+  InvalidInput:
+    type: "string"
+    format: "string"
+`), &spec2)
+	yaml.Unmarshal([]byte(`
+swagger: "2.0"
+paths:
+  /test:
+    post:
+      tags:
+      - "test"
+      summary: "Test API"
+      operationId: "addTest"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test"
+      responses:
+        405:
+          description: "Invalid input"
+          $ref: "#/definitions/InvalidInput"
+  /othertest:
+    post:
+      tags:
+      - "test2"
+      summary: "Test2 API"
+      operationId: "addTest2"
+      consumes:
+      - "application/json"
+      produces:
+      - "application/xml"
+      parameters:
+      - in: "body"
+        name: "body"
+        description: "test2 object"
+        required: true
+        schema:
+          $ref: "#/definitions/Test_v2"
+definitions:
+  Test:
+    type: "object"
+    properties:
+      id:
+        type: "integer"
+        format: "int64"
+      status:
+        type: "string"
+        description: "Status"
+  Test_v2:
+    description: "This Test has a description"
+    type: "object"
+    properties:
+      id:
+        type: "integer"
+        format: "int64"
+  InvalidInput:
+    type: "string"
+    format: "string"
+`), &expected)
+	assert := assert.New(t)
+	if !assert.NoError(MergeSpecs(spec1, spec2)) {
+		return
+	}
+
+	expected_yaml, _ := yaml.Marshal(expected)
+	spec1_yaml, _ := yaml.Marshal(spec1)
+
+	assert.Equal(string(expected_yaml), string(spec1_yaml))
+}

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

@@ -17,8 +17,11 @@ limitations under the License.
 package apiserver
 
 import (
+	"context"
+	"encoding/json"
 	"net/http"
 	"net/url"
+	"sync"
 	"time"
 
 	"k8s.io/apimachinery/pkg/apimachinery/announced"
@@ -37,6 +40,14 @@ import (
 	listersv1 "k8s.io/client-go/listers/core/v1"
 	"k8s.io/client-go/pkg/version"
 
+	"bytes"
+	"fmt"
+	"github.com/go-openapi/spec"
+	"github.com/golang/glog"
+	"github.com/pkg/errors"
+	"io"
+	"k8s.io/apiserver/pkg/server/openapi"
+	"k8s.io/client-go/transport"
 	"k8s.io/kube-aggregator/pkg/apis/apiregistration"
 	"k8s.io/kube-aggregator/pkg/apis/apiregistration/install"
 	"k8s.io/kube-aggregator/pkg/apis/apiregistration/v1beta1"
@@ -54,6 +65,10 @@ var (
 	Codecs               = serializer.NewCodecFactory(Scheme)
 )
 
+const (
+	LOAD_OPENAPI_SPEC_MAX_RETRIES = 10
+)
+
 func init() {
 	install.Install(groupFactoryRegistry, registry, Scheme)
 
@@ -118,6 +133,24 @@ type APIAggregator struct {
 	// handledGroups are the groups that already have routes
 	handledGroups sets.String
 
+	// Swagger spec for each api service
+	apiServiceSpecs map[string]*spec.Swagger
+
+	// List of the specs that needs to be loaded. When a spec is successfully loaded
+	// it will be removed from this list and added to apiServiceSpecs.
+	// Map values are retry counts. After a preset retries, it will stop
+	// trying.
+	toLoadAPISpec map[string]int
+
+	// protecting toLoadAPISpec and apiServiceSpecs
+	specMutex sync.Mutex
+
+	// rootSpec is the OpenAPI spec of the Aggregator server.
+	rootSpec *spec.Swagger
+
+	// delegationSpec is the delegation API Server's spec (most of API groups are in this spec).
+	delegationSpec *spec.Swagger
+
 	// lister is used to add group handling for /apis/<group> aggregator lookups based on
 	// controller state
 	lister listers.APIServiceLister
@@ -191,11 +224,14 @@ func (c completedConfig) NewWithDelegate(delegationTarget genericapiserver.Deleg
 	s := &APIAggregator{
 		GenericAPIServer: genericServer,
 		delegateHandler:  delegationTarget.UnprotectedHandler(),
+		delegationSpec:   delegationTarget.OpenAPISpec(),
 		contextMapper:    c.GenericConfig.RequestContextMapper,
 		proxyClientCert:  c.ProxyClientCert,
 		proxyClientKey:   c.ProxyClientKey,
 		proxyTransport:   proxyTransport,
 		proxyHandlers:    map[string]*proxyHandler{},
+		apiServiceSpecs:  map[string]*spec.Swagger{},
+		toLoadAPISpec:    map[string]int{},
 		handledGroups:    sets.String{},
 		lister:           informerFactory.Apiregistration().InternalVersion().APIServices().Lister(),
 		APIRegistrationInformers: informerFactory,
@@ -244,6 +280,20 @@ func (c completedConfig) NewWithDelegate(delegationTarget genericapiserver.Deleg
 		return nil
 	})
 
+	s.GenericAPIServer.PrepareOpenAPIService()
+
+	if s.GenericAPIServer.OpenAPIService != nil {
+		s.rootSpec = s.GenericAPIServer.OpenAPIService.GetSpec()
+		if err := s.updateOpenAPISpec(); err != nil {
+			return nil, err
+		}
+		s.GenericAPIServer.OpenAPIService.AddUpdateHook(func(r *http.Request) {
+			if s.tryLoadingOpenAPISpecs(r) {
+				s.updateOpenAPISpec()
+			}
+		})
+	}
+
 	return s, nil
 }
 
@@ -274,6 +324,9 @@ func (s *APIAggregator) AddAPIService(apiService *apiregistration.APIService) {
 	}
 	proxyHandler.updateAPIService(apiService)
 	s.proxyHandlers[apiService.Name] = proxyHandler
+
+	s.deferLoadAPISpec(apiService.Name)
+
 	s.GenericAPIServer.Handler.NonGoRestfulMux.Handle(proxyPath, proxyHandler)
 	s.GenericAPIServer.Handler.NonGoRestfulMux.UnlistedHandlePrefix(proxyPath+"/", proxyHandler)
 
@@ -302,6 +355,19 @@ func (s *APIAggregator) AddAPIService(apiService *apiregistration.APIService) {
 	s.handledGroups.Insert(apiService.Spec.Group)
 }
 
+func (s *APIAggregator) deferLoadAPISpec(name string) {
+	s.specMutex.Lock()
+	defer s.specMutex.Unlock()
+	s.toLoadAPISpec[name] = 0
+}
+
+func (s *APIAggregator) deleteApiSpec(name string) {
+	s.specMutex.Lock()
+	defer s.specMutex.Unlock()
+	delete(s.apiServiceSpecs, name)
+	delete(s.toLoadAPISpec, name)
+}
+
 // RemoveAPIService removes the APIService from being handled.  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) RemoveAPIService(apiServiceName string) {
@@ -315,7 +381,124 @@ func (s *APIAggregator) RemoveAPIService(apiServiceName string) {
 	s.GenericAPIServer.Handler.NonGoRestfulMux.Unregister(proxyPath)
 	s.GenericAPIServer.Handler.NonGoRestfulMux.Unregister(proxyPath + "/")
 	delete(s.proxyHandlers, apiServiceName)
+	s.deleteApiSpec(apiServiceName)
+	s.updateOpenAPISpec()
 
 	// TODO unregister group level discovery when there are no more versions for the group
 	// We don't need this right away because the handler properly delegates when no versions are present
 }
+
+func (_ *APIAggregator) loadOpenAPISpec(p *proxyHandler, r *http.Request) (*spec.Swagger, error) {
+	value := p.handlingInfo.Load()
+	if value == nil {
+		return nil, nil
+	}
+	handlingInfo := value.(proxyHandlingInfo)
+	if handlingInfo.local {
+		return nil, nil
+	}
+	loc, err := p.routing.ResolveEndpoint(handlingInfo.serviceNamespace, handlingInfo.serviceName)
+	if err != nil {
+		return nil, fmt.Errorf("missing route")
+	}
+	host := loc.Host
+
+	var w io.Reader
+	req, err := http.NewRequest("GET", "/swagger.json", w)
+	if err != nil {
+		return nil, err
+	}
+	req.URL.Scheme = "https"
+	req.URL.Host = host
+
+	req = req.WithContext(context.Background())
+	// Get user from the original request
+	ctx, ok := p.contextMapper.Get(r)
+	if !ok {
+		return nil, fmt.Errorf("missing context")
+	}
+	user, ok := genericapirequest.UserFrom(ctx)
+	if !ok {
+		return nil, fmt.Errorf("missing user")
+	}
+	proxyRoundTripper := transport.NewAuthProxyRoundTripper(user.GetName(), user.GetGroups(), user.GetExtra(), handlingInfo.proxyRoundTripper)
+	res, err := proxyRoundTripper.RoundTrip(req)
+	if err != nil {
+		return nil, err
+	}
+	if res.StatusCode != http.StatusOK {
+		return nil, errors.New(res.Status)
+	}
+	buf := new(bytes.Buffer)
+	buf.ReadFrom(res.Body)
+	bytes := buf.Bytes()
+	var s spec.Swagger
+	if err := json.Unmarshal(bytes, &s); err != nil {
+		return nil, err
+	}
+	return &s, nil
+}
+
+// Returns true if any Spec is loaded
+func (s *APIAggregator) tryLoadingOpenAPISpecs(r *http.Request) bool {
+	s.specMutex.Lock()
+	defer s.specMutex.Unlock()
+	if len(s.toLoadAPISpec) == 0 {
+		return false
+	}
+	loaded := false
+	newList := map[string]int{}
+	for name, retries := range s.toLoadAPISpec {
+		if retries >= LOAD_OPENAPI_SPEC_MAX_RETRIES {
+			continue
+		}
+		proxyHandler := s.proxyHandlers[name]
+		if spec, err := s.loadOpenAPISpec(proxyHandler, r); err != nil {
+			glog.Warningf("Failed to Load OpenAPI spec (try %d of %d) for %s, err=%s", retries+1, LOAD_OPENAPI_SPEC_MAX_RETRIES, name, err)
+			newList[name] = retries + 1
+		} else if spec != nil {
+			s.apiServiceSpecs[name] = spec
+			loaded = true
+		}
+		s.toLoadAPISpec = newList
+	}
+	return loaded
+}
+
+func (s *APIAggregator) updateOpenAPISpec() error {
+	s.specMutex.Lock()
+	defer s.specMutex.Unlock()
+	if s.GenericAPIServer.OpenAPIService == nil {
+		return nil
+	}
+	sp, err := openapi.CloneSpec(s.rootSpec)
+	if err != nil {
+		return err
+	}
+	openapi.FilterSpecByPaths(sp, []string{"/apis/apiregistration.k8s.io/"})
+	if _, found := sp.Paths.Paths["/version/"]; found {
+		return fmt.Errorf("Cleanup didn't work")
+	}
+	if err := openapi.MergeSpecs(sp, s.delegationSpec); err != nil {
+		return err
+	}
+
+	for k, v := range s.apiServiceSpecs {
+		version := apiregistration.APIServiceNameToGroupVersion(k)
+
+		proxyPath := "/apis/" + version.Group + "/"
+		// v1. is a special case for the legacy API.  It proxies to a wider set of endpoints.
+		if k == legacyAPIServiceName {
+			proxyPath = "/api/"
+		}
+		spc, err := openapi.CloneSpec(v)
+		if err != nil {
+			return err
+		}
+		openapi.FilterSpecByPaths(spc, []string{proxyPath})
+		if err := openapi.MergeSpecs(sp, spc); err != nil {
+			return err
+		}
+	}
+	return s.GenericAPIServer.OpenAPIService.UpdateSpec(sp)
+}