api_installer.go

/*
Copyright 2015 Google Inc. 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 apiserver

import (
	"fmt"
	"net/http"
	"net/url"
	gpath "path"
	"reflect"
	"sort"
	"strings"

	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/errors"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/meta"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/rest"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/conversion"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
	watchjson "github.com/GoogleCloudPlatform/kubernetes/pkg/watch/json"

	"github.com/emicklei/go-restful"
)

type APIInstaller struct {
	group  *APIGroupVersion
	info   *APIRequestInfoResolver
	prefix string // Path prefix where API resources are to be registered.
}

// Struct capturing information about an action ("GET", "POST", "WATCH", PROXY", etc).
type action struct {
	Verb   string               // Verb identifying the action ("GET", "POST", "WATCH", PROXY", etc).
	Path   string               // The path of the action
	Params []*restful.Parameter // List of parameters associated with the action.
	Namer  ScopeNamer
}

// errEmptyName is returned when API requests do not fill the name section of the path.
var errEmptyName = errors.NewBadRequest("name must be provided")

// Installs handlers for API resources.
func (a *APIInstaller) Install() (ws *restful.WebService, errors []error) {
	errors = make([]error, 0)

	// Create the WebService.
	ws = a.newWebService()

	redirectHandler := (&RedirectHandler{a.group.Storage, a.group.Codec, a.group.Context, a.info})
	proxyHandler := (&ProxyHandler{a.prefix + "/proxy/", a.group.Storage, a.group.Codec, a.group.Context, a.info})

	// Register the paths in a deterministic (sorted) order to get a deterministic swagger spec.
	paths := make([]string, len(a.group.Storage))
	var i int = 0
	for path := range a.group.Storage {
		paths[i] = path
		i++
	}
	sort.Strings(paths)
	for _, path := range paths {
		if err := a.registerResourceHandlers(path, a.group.Storage[path], ws, redirectHandler, proxyHandler); err != nil {
			errors = append(errors, err)
		}
	}
	return ws, errors
}

func (a *APIInstaller) newWebService() *restful.WebService {
	ws := new(restful.WebService)
	ws.Path(a.prefix)
	ws.Doc("API at " + a.prefix + " version " + a.group.Version)
	// TODO: change to restful.MIME_JSON when we set content type in client
	ws.Consumes("*/*")
	ws.Produces(restful.MIME_JSON)
	ws.ApiVersion(a.group.Version)

	return ws
}

func (a *APIInstaller) registerResourceHandlers(path string, storage rest.Storage, ws *restful.WebService, redirectHandler, proxyHandler http.Handler) error {
	admit := a.group.Admit
	context := a.group.Context

	serverVersion := a.group.ServerVersion
	if len(serverVersion) == 0 {
		serverVersion = a.group.Version
	}

	var resource, subresource string
	switch parts := strings.Split(path, "/"); len(parts) {
	case 2:
		resource, subresource = parts[0], parts[1]
	case 1:
		resource = parts[0]
	default:
		// TODO: support deeper paths
		return fmt.Errorf("api_installer allows only one or two segment paths (resource or resource/subresource)")
	}
	hasSubresource := len(subresource) > 0

	object := storage.New()
	_, kind, err := a.group.Typer.ObjectVersionAndKind(object)
	if err != nil {
		return err
	}
	versionedPtr, err := a.group.Creater.New(a.group.Version, kind)
	if err != nil {
		return err
	}
	versionedObject := indirectArbitraryPointer(versionedPtr)

	mapping, err := a.group.Mapper.RESTMapping(kind, a.group.Version)
	if err != nil {
		return err
	}

	// what verbs are supported by the storage, used to know what verbs we support per path
	creater, isCreater := storage.(rest.Creater)
	lister, isLister := storage.(rest.Lister)
	getter, isGetter := storage.(rest.Getter)
	getterWithOptions, isGetterWithOptions := storage.(rest.GetterWithOptions)
	deleter, isDeleter := storage.(rest.Deleter)
	gracefulDeleter, isGracefulDeleter := storage.(rest.GracefulDeleter)
	updater, isUpdater := storage.(rest.Updater)
	patcher, isPatcher := storage.(rest.Patcher)
	watcher, isWatcher := storage.(rest.Watcher)
	_, isRedirector := storage.(rest.Redirector)
	connecter, isConnecter := storage.(rest.Connecter)
	storageMeta, isMetadata := storage.(rest.StorageMetadata)
	if !isMetadata {
		storageMeta = defaultStorageMetadata{}
	}

	var versionedList interface{}
	if isLister {
		list := lister.NewList()
		_, listKind, err := a.group.Typer.ObjectVersionAndKind(list)
		versionedListPtr, err := a.group.Creater.New(a.group.Version, listKind)
		if err != nil {
			return err
		}
		versionedList = indirectArbitraryPointer(versionedListPtr)
	}

	versionedListOptions, err := a.group.Creater.New(serverVersion, "ListOptions")
	if err != nil {
		return err
	}

	var versionedDeleterObject interface{}
	switch {
	case isGracefulDeleter:
		objectPtr, err := a.group.Creater.New(serverVersion, "DeleteOptions")
		if err != nil {
			return err
		}
		versionedDeleterObject = indirectArbitraryPointer(objectPtr)
		isDeleter = true
	case isDeleter:
		gracefulDeleter = rest.GracefulDeleteAdapter{deleter}
	}

	versionedStatusPtr, err := a.group.Creater.New(serverVersion, "Status")
	if err != nil {
		return err
	}
	versionedStatus := indirectArbitraryPointer(versionedStatusPtr)
	var (
		getOptions     runtime.Object
		getOptionsKind string
		getSubpath     bool
		getSubpathKey  string
	)
	if isGetterWithOptions {
		getOptions, getSubpath, getSubpathKey = getterWithOptions.NewGetOptions()
		_, getOptionsKind, err = a.group.Typer.ObjectVersionAndKind(getOptions)
		if err != nil {
			return err
		}
		isGetter = true
	}

	var (
		connectOptions     runtime.Object
		connectOptionsKind string
		connectSubpath     bool
		connectSubpathKey  string
	)
	if isConnecter {
		connectOptions, connectSubpath, connectSubpathKey = connecter.NewConnectOptions()
		if connectOptions != nil {
			_, connectOptionsKind, err = a.group.Typer.ObjectVersionAndKind(connectOptions)
			if err != nil {
				return err
			}
		}
	}

	var ctxFn ContextFunc
	ctxFn = func(req *restful.Request) api.Context {
		if ctx, ok := context.Get(req.Request); ok {
			return ctx
		}
		return api.NewContext()
	}

	allowWatchList := isWatcher && isLister // watching on lists is allowed only for kinds that support both watch and list.
	scope := mapping.Scope
	nameParam := ws.PathParameter("name", "name of the "+kind).DataType("string")
	pathParam := ws.PathParameter("path:*", "path to the resource").DataType("string")
	params := []*restful.Parameter{}
	actions := []action{}

	// Get the list of actions for the given scope.
	if scope.Name() != meta.RESTScopeNameNamespace {
		resourcePath := resource
		resourceParams := params
		itemPath := resourcePath + "/{name}"
		nameParams := append(params, nameParam)
		proxyParams := append(nameParams, pathParam)
		if hasSubresource {
			itemPath = itemPath + "/" + subresource
			resourcePath = itemPath
			resourceParams = nameParams
		}
		namer := rootScopeNaming{scope, a.group.Linker, gpath.Join(a.prefix, itemPath)}

		// Handler for standard REST verbs (GET, PUT, POST and DELETE).
		actions = appendIf(actions, action{"LIST", resourcePath, resourceParams, namer}, isLister)
		actions = appendIf(actions, action{"POST", resourcePath, resourceParams, namer}, isCreater)
		actions = appendIf(actions, action{"WATCHLIST", "watch/" + resourcePath, resourceParams, namer}, allowWatchList)

		actions = appendIf(actions, action{"GET", itemPath, nameParams, namer}, isGetter)
		if getSubpath {
			actions = appendIf(actions, action{"GET", itemPath + "/{path:*}", proxyParams, namer}, isGetter)
		}
		actions = appendIf(actions, action{"PUT", itemPath, nameParams, namer}, isUpdater)
		actions = appendIf(actions, action{"PATCH", itemPath, nameParams, namer}, isPatcher)
		actions = appendIf(actions, action{"DELETE", itemPath, nameParams, namer}, isDeleter)
		actions = appendIf(actions, action{"WATCH", "watch/" + itemPath, nameParams, namer}, isWatcher)
		actions = appendIf(actions, action{"REDIRECT", "redirect/" + itemPath, nameParams, namer}, isRedirector)
		actions = appendIf(actions, action{"PROXY", "proxy/" + itemPath + "/{path:*}", proxyParams, namer}, isRedirector)
		actions = appendIf(actions, action{"PROXY", "proxy/" + itemPath, nameParams, namer}, isRedirector)
		actions = appendIf(actions, action{"CONNECT", itemPath, nameParams, namer}, isConnecter)
		actions = appendIf(actions, action{"CONNECT", itemPath + "/{path:*}", nameParams, namer}, isConnecter && connectSubpath)

	} else {
		// v1beta3 format with namespace in path
		if scope.ParamPath() {
			// Handler for standard REST verbs (GET, PUT, POST and DELETE).
			namespaceParam := ws.PathParameter(scope.ParamName(), scope.ParamDescription()).DataType("string")
			namespacedPath := scope.ParamName() + "/{" + scope.ParamName() + "}/" + resource
			namespaceParams := []*restful.Parameter{namespaceParam}

			resourcePath := namespacedPath
			resourceParams := namespaceParams
			itemPath := namespacedPath + "/{name}"
			nameParams := append(namespaceParams, nameParam)
			proxyParams := append(nameParams, pathParam)
			if hasSubresource {
				itemPath = itemPath + "/" + subresource
				resourcePath = itemPath
				resourceParams = nameParams
			}
			namer := scopeNaming{scope, a.group.Linker, gpath.Join(a.prefix, itemPath), false}

			actions = appendIf(actions, action{"LIST", resourcePath, resourceParams, namer}, isLister)
			actions = appendIf(actions, action{"POST", resourcePath, resourceParams, namer}, isCreater)
			// DEPRECATED
			actions = appendIf(actions, action{"WATCHLIST", "watch/" + resourcePath, resourceParams, namer}, allowWatchList)

			actions = appendIf(actions, action{"GET", itemPath, nameParams, namer}, isGetter)
			if getSubpath {
				actions = appendIf(actions, action{"GET", itemPath + "/{path:*}", proxyParams, namer}, isGetter)
			}
			actions = appendIf(actions, action{"PUT", itemPath, nameParams, namer}, isUpdater)
			actions = appendIf(actions, action{"PATCH", itemPath, nameParams, namer}, isPatcher)
			actions = appendIf(actions, action{"DELETE", itemPath, nameParams, namer}, isDeleter)
			actions = appendIf(actions, action{"WATCH", "watch/" + itemPath, nameParams, namer}, isWatcher)
			actions = appendIf(actions, action{"REDIRECT", "redirect/" + itemPath, nameParams, namer}, isRedirector)
			actions = appendIf(actions, action{"PROXY", "proxy/" + itemPath + "/{path:*}", proxyParams, namer}, isRedirector)
			actions = appendIf(actions, action{"PROXY", "proxy/" + itemPath, nameParams, namer}, isRedirector)
			actions = appendIf(actions, action{"CONNECT", itemPath, nameParams, namer}, isConnecter)
			actions = appendIf(actions, action{"CONNECT", itemPath + "/{path:*}", nameParams, namer}, isConnecter && connectSubpath)

			// list across namespace.
			namer = scopeNaming{scope, a.group.Linker, gpath.Join(a.prefix, itemPath), true}
			actions = appendIf(actions, action{"LIST", resource, params, namer}, isLister)
			actions = appendIf(actions, action{"WATCHLIST", "watch/" + resource, params, namer}, allowWatchList)

		} else {
			// Handler for standard REST verbs (GET, PUT, POST and DELETE).
			// v1beta1/v1beta2 format where namespace was a query parameter
			namespaceParam := ws.QueryParameter(scope.ParamName(), scope.ParamDescription()).DataType("string")
			namespaceParams := []*restful.Parameter{namespaceParam}

			basePath := resource
			resourcePath := basePath
			resourceParams := namespaceParams
			itemPath := resourcePath + "/{name}"
			nameParams := append(namespaceParams, nameParam)
			proxyParams := append(nameParams, pathParam)
			if hasSubresource {
				itemPath = itemPath + "/" + subresource
				resourcePath = itemPath
				resourceParams = nameParams
			}
			namer := legacyScopeNaming{scope, a.group.Linker, gpath.Join(a.prefix, itemPath)}

			actions = appendIf(actions, action{"LIST", resourcePath, resourceParams, namer}, isLister)
			actions = appendIf(actions, action{"POST", resourcePath, resourceParams, namer}, isCreater)
			actions = appendIf(actions, action{"WATCHLIST", "watch/" + resourcePath, resourceParams, namer}, allowWatchList)

			actions = appendIf(actions, action{"GET", itemPath, nameParams, namer}, isGetter)
			if getSubpath {
				actions = appendIf(actions, action{"GET", itemPath + "/{path:*}", proxyParams, namer}, isGetter)
			}
			actions = appendIf(actions, action{"PUT", itemPath, nameParams, namer}, isUpdater)
			actions = appendIf(actions, action{"PATCH", itemPath, nameParams, namer}, isPatcher)
			actions = appendIf(actions, action{"DELETE", itemPath, nameParams, namer}, isDeleter)
			actions = appendIf(actions, action{"WATCH", "watch/" + itemPath, nameParams, namer}, isWatcher)
			actions = appendIf(actions, action{"REDIRECT", "redirect/" + itemPath, nameParams, namer}, isRedirector)
			actions = appendIf(actions, action{"PROXY", "proxy/" + itemPath + "/{path:*}", proxyParams, namer}, isRedirector)
			actions = appendIf(actions, action{"PROXY", "proxy/" + itemPath, nameParams, namer}, isRedirector)
			actions = appendIf(actions, action{"CONNECT", itemPath, nameParams, namer}, isConnecter)
			actions = appendIf(actions, action{"CONNECT", itemPath + "/{path:*}", nameParams, namer}, isConnecter && connectSubpath)
		}
	}

	// Create Routes for the actions.
	// TODO: Add status documentation using Returns()
	// Errors (see api/errors/errors.go as well as go-restful router):
	// http.StatusNotFound, http.StatusMethodNotAllowed,
	// http.StatusUnsupportedMediaType, http.StatusNotAcceptable,
	// http.StatusBadRequest, http.StatusUnauthorized, http.StatusForbidden,
	// http.StatusRequestTimeout, http.StatusConflict, http.StatusPreconditionFailed,
	// 422 (StatusUnprocessableEntity), http.StatusInternalServerError,
	// http.StatusServiceUnavailable
	// and api error codes
	// Note that if we specify a versioned Status object here, we may need to
	// create one for the tests, also
	// Success:
	// http.StatusOK, http.StatusCreated, http.StatusAccepted, http.StatusNoContent
	//
	// test/integration/auth_test.go is currently the most comprehensive status code test

	reqScope := RequestScope{
		ContextFunc:      ctxFn,
		Creater:          a.group.Creater,
		Convertor:        a.group.Convertor,
		Codec:            mapping.Codec,
		APIVersion:       a.group.Version,
		ServerAPIVersion: serverVersion,
		Resource:         resource,
		Kind:             kind,
	}
	for _, action := range actions {
		reqScope.Namer = action.Namer
		m := monitorFilter(action.Verb, resource)
		switch action.Verb {
		case "GET": // Get a resource.
			var handler restful.RouteFunction
			if isGetterWithOptions {
				handler = GetResourceWithOptions(getterWithOptions, reqScope, getOptionsKind, getSubpath, getSubpathKey)
			} else {
				handler = GetResource(getter, reqScope)
			}
			route := ws.GET(action.Path).To(handler).
				Filter(m).
				Doc("read the specified "+kind).
				Operation("read"+kind).
				Produces(append(storageMeta.ProducesMIMETypes(action.Verb), "application/json")...).
				Returns(http.StatusOK, "OK", versionedObject).
				Writes(versionedObject)
			if isGetterWithOptions {
				if err := addObjectParams(ws, route, getOptions); err != nil {
					return err
				}
			}
			addParams(route, action.Params)
			ws.Route(route)
		case "LIST": // List all resources of a kind.
			route := ws.GET(action.Path).To(ListResource(lister, watcher, reqScope, false)).
				Filter(m).
				Doc("list objects of kind "+kind).
				Operation("list"+kind).
				Produces("application/json").
				Returns(http.StatusOK, "OK", versionedList).
				Writes(versionedList)
			if err := addObjectParams(ws, route, versionedListOptions); err != nil {
				return err
			}
			switch {
			case isLister && isWatcher:
				route.Doc("list or watch objects of kind " + kind)
			case isWatcher:
				route.Doc("watch objects of kind " + kind)
			}
			addParams(route, action.Params)
			ws.Route(route)
		case "PUT": // Update a resource.
			route := ws.PUT(action.Path).To(UpdateResource(updater, reqScope, a.group.Typer, admit)).
				Filter(m).
				Doc("replace the specified "+kind).
				Operation("replace"+kind).
				Produces(append(storageMeta.ProducesMIMETypes(action.Verb), "application/json")...).
				Returns(http.StatusOK, "OK", versionedObject).
				Reads(versionedObject).
				Writes(versionedObject)
			addParams(route, action.Params)
			ws.Route(route)
		case "PATCH": // Partially update a resource
			route := ws.PATCH(action.Path).To(PatchResource(patcher, reqScope, a.group.Typer, admit, mapping.ObjectConvertor)).
				Filter(m).
				Doc("partially update the specified "+kind).
				Consumes(string(api.JSONPatchType), string(api.MergePatchType), string(api.StrategicMergePatchType)).
				Operation("patch"+kind).
				Produces(append(storageMeta.ProducesMIMETypes(action.Verb), "application/json")...).
				Returns(http.StatusOK, "OK", "string").
				Reads("string").
				Writes(versionedObject)
			addParams(route, action.Params)
			ws.Route(route)
		case "POST": // Create a resource.
			route := ws.POST(action.Path).To(CreateResource(creater, reqScope, a.group.Typer, admit)).
				Filter(m).
				Doc("create a "+kind).
				Operation("create"+kind).
				Produces(append(storageMeta.ProducesMIMETypes(action.Verb), "application/json")...).
				Returns(http.StatusOK, "OK", versionedObject).
				Reads(versionedObject).
				Writes(versionedObject)
			addParams(route, action.Params)
			ws.Route(route)
		case "DELETE": // Delete a resource.
			route := ws.DELETE(action.Path).To(DeleteResource(gracefulDeleter, isGracefulDeleter, reqScope, admit)).
				Filter(m).
				Doc("delete a "+kind).
				Operation("delete"+kind).
				Produces(append(storageMeta.ProducesMIMETypes(action.Verb), "application/json")...).
				Writes(versionedStatus).
				Returns(http.StatusOK, "OK", versionedStatus)
			if isGracefulDeleter {
				route.Reads(versionedDeleterObject)
			}
			addParams(route, action.Params)
			ws.Route(route)
		// TODO: deprecated
		case "WATCH": // Watch a resource.
			route := ws.GET(action.Path).To(ListResource(lister, watcher, reqScope, true)).
				Filter(m).
				Doc("watch changes to an object of kind "+kind).
				Operation("watch"+kind).
				Produces("application/json").
				Returns(http.StatusOK, "OK", watchjson.WatchEvent{}).
				Writes(watchjson.WatchEvent{})
			if err := addObjectParams(ws, route, versionedListOptions); err != nil {
				return err
			}
			addParams(route, action.Params)
			ws.Route(route)
		// TODO: deprecated
		case "WATCHLIST": // Watch all resources of a kind.
			route := ws.GET(action.Path).To(ListResource(lister, watcher, reqScope, true)).
				Filter(m).
				Doc("watch individual changes to a list of "+kind).
				Operation("watch"+kind+"list").
				Produces("application/json").
				Returns(http.StatusOK, "OK", watchjson.WatchEvent{}).
				Writes(watchjson.WatchEvent{})
			if err := addObjectParams(ws, route, versionedListOptions); err != nil {
				return err
			}
			addParams(route, action.Params)
			ws.Route(route)
		case "REDIRECT": // Get the redirect URL for a resource.
			route := ws.GET(action.Path).To(routeFunction(redirectHandler)).
				Filter(m).
				Doc("redirect GET request to " + kind).
				Operation("redirect" + kind).
				Produces("*/*").
				Consumes("*/*").
				Writes("string")
			addParams(route, action.Params)
			ws.Route(route)
		case "PROXY": // Proxy requests to a resource.
			// Accept all methods as per https://github.com/GoogleCloudPlatform/kubernetes/issues/3996
			addProxyRoute(ws, "GET", a.prefix, action.Path, proxyHandler, kind, resource, action.Params)
			addProxyRoute(ws, "PUT", a.prefix, action.Path, proxyHandler, kind, resource, action.Params)
			addProxyRoute(ws, "POST", a.prefix, action.Path, proxyHandler, kind, resource, action.Params)
			addProxyRoute(ws, "DELETE", a.prefix, action.Path, proxyHandler, kind, resource, action.Params)
		case "CONNECT":
			for _, method := range connecter.ConnectMethods() {
				route := ws.Method(method).Path(action.Path).
					To(ConnectResource(connecter, reqScope, connectOptionsKind, connectSubpath, connectSubpathKey)).
					Filter(m).
					Doc("connect " + method + " requests to " + kind).
					Operation("connect" + method + kind).
					Produces("*/*").
					Consumes("*/*").
					Writes("string")
				if connectOptions != nil {
					if err := addObjectParams(ws, route, connectOptions); err != nil {
						return err
					}
				}
				ws.Route(route)
			}
		default:
			return fmt.Errorf("unrecognized action verb: %s", action.Verb)
		}
		// Note: update GetAttribs() when adding a custom handler.
	}
	return nil
}

// rootScopeNaming reads only names from a request and ignores namespaces. It implements ScopeNamer
// for root scoped resources.
type rootScopeNaming struct {
	scope meta.RESTScope
	runtime.SelfLinker
	itemPath string
}

// rootScopeNaming implements ScopeNamer
var _ ScopeNamer = rootScopeNaming{}

// Namespace returns an empty string because root scoped objects have no namespace.
func (n rootScopeNaming) Namespace(req *restful.Request) (namespace string, err error) {
	return "", nil
}

// Name returns the name from the path and an empty string for namespace, or an error if the
// name is empty.
func (n rootScopeNaming) Name(req *restful.Request) (namespace, name string, err error) {
	name = req.PathParameter("name")
	if len(name) == 0 {
		return "", "", errEmptyName
	}
	return "", name, nil
}

// GenerateLink returns the appropriate path and query to locate an object by its canonical path.
func (n rootScopeNaming) GenerateLink(req *restful.Request, obj runtime.Object) (path, query string, err error) {
	_, name, err := n.ObjectName(obj)
	if err != nil {
		return "", "", err
	}
	if len(name) == 0 {
		_, name, err = n.Name(req)
		if err != nil {
			return "", "", err
		}
	}
	path = strings.Replace(n.itemPath, "{name}", name, 1)
	return path, "", nil
}

// GenerateListLink returns the appropriate path and query to locate a list by its canonical path.
func (n rootScopeNaming) GenerateListLink(req *restful.Request) (path, query string, err error) {
	path = req.Request.URL.Path
	return path, "", nil
}

// ObjectName returns the name set on the object, or an error if the
// name cannot be returned. Namespace is empty
// TODO: distinguish between objects with name/namespace and without via a specific error.
func (n rootScopeNaming) ObjectName(obj runtime.Object) (namespace, name string, err error) {
	name, err = n.SelfLinker.Name(obj)
	if err != nil {
		return "", "", err
	}
	if len(name) == 0 {
		return "", "", errEmptyName
	}
	return "", name, nil
}

// scopeNaming returns naming information from a request. It implements ScopeNamer for
// namespace scoped resources.
type scopeNaming struct {
	scope meta.RESTScope
	runtime.SelfLinker
	itemPath      string
	allNamespaces bool
}

// scopeNaming implements ScopeNamer
var _ ScopeNamer = scopeNaming{}

// Namespace returns the namespace from the path or the default.
func (n scopeNaming) Namespace(req *restful.Request) (namespace string, err error) {
	if n.allNamespaces {
		return "", nil
	}
	namespace = req.PathParameter(n.scope.ParamName())
	if len(namespace) == 0 {
		// a URL was constructed without the namespace, or this method was invoked
		// on an object without a namespace path parameter.
		return "", fmt.Errorf("no namespace parameter found on request")
	}
	return namespace, nil
}

// Name returns the name from the path, the namespace (or default), or an error if the
// name is empty.
func (n scopeNaming) Name(req *restful.Request) (namespace, name string, err error) {
	namespace, _ = n.Namespace(req)
	name = req.PathParameter("name")
	if len(name) == 0 {
		return "", "", errEmptyName
	}
	return
}

// GenerateLink returns the appropriate path and query to locate an object by its canonical path.
func (n scopeNaming) GenerateLink(req *restful.Request, obj runtime.Object) (path, query string, err error) {
	namespace, name, err := n.ObjectName(obj)
	if err != nil {
		return "", "", err
	}
	if len(namespace) == 0 && len(name) == 0 {
		namespace, name, err = n.Name(req)
		if err != nil {
			return "", "", err
		}
	}
	path = strings.Replace(n.itemPath, "{name}", name, 1)
	path = strings.Replace(path, "{"+n.scope.ParamName()+"}", namespace, 1)
	return path, "", nil
}

// GenerateListLink returns the appropriate path and query to locate a list by its canonical path.
func (n scopeNaming) GenerateListLink(req *restful.Request) (path, query string, err error) {
	path = req.Request.URL.Path
	return path, "", nil
}

// ObjectName returns the name and namespace set on the object, or an error if the
// name cannot be returned.
// TODO: distinguish between objects with name/namespace and without via a specific error.
func (n scopeNaming) ObjectName(obj runtime.Object) (namespace, name string, err error) {
	name, err = n.SelfLinker.Name(obj)
	if err != nil {
		return "", "", err
	}
	namespace, err = n.SelfLinker.Namespace(obj)
	if err != nil {
		return "", "", err
	}
	return namespace, name, err
}

// legacyScopeNaming modifies a scopeNaming to read namespace from the query. It implements
// ScopeNamer for older query based namespace parameters.
type legacyScopeNaming struct {
	scope meta.RESTScope
	runtime.SelfLinker
	itemPath string
}

// legacyScopeNaming implements ScopeNamer
var _ ScopeNamer = legacyScopeNaming{}

// Namespace returns the namespace from the query or the default.
func (n legacyScopeNaming) Namespace(req *restful.Request) (namespace string, err error) {
	values, ok := req.Request.URL.Query()[n.scope.ParamName()]
	if !ok || len(values) == 0 {
		// legacy behavior
		if req.Request.Method == "POST" || len(req.PathParameter("name")) > 0 {
			return api.NamespaceDefault, nil
		}
		return api.NamespaceAll, nil
	}
	return values[0], nil
}

// Name returns the name from the path, the namespace (or default), or an error if the
// name is empty.
func (n legacyScopeNaming) Name(req *restful.Request) (namespace, name string, err error) {
	namespace, _ = n.Namespace(req)
	name = req.PathParameter("name")
	if len(name) == 0 {
		return "", "", errEmptyName
	}
	return namespace, name, nil
}

// GenerateLink returns the appropriate path and query to locate an object by its canonical path.
func (n legacyScopeNaming) GenerateLink(req *restful.Request, obj runtime.Object) (path, query string, err error) {
	namespace, name, err := n.ObjectName(obj)
	if err != nil {
		return "", "", err
	}
	if len(name) == 0 {
		return "", "", errEmptyName
	}
	path = strings.Replace(n.itemPath, "{name}", name, -1)
	values := make(url.Values)
	values.Set(n.scope.ParamName(), namespace)
	query = values.Encode()
	return path, query, nil
}

// GenerateListLink returns the appropriate path and query to locate a list by its canonical path.
func (n legacyScopeNaming) GenerateListLink(req *restful.Request) (path, query string, err error) {
	namespace, err := n.Namespace(req)
	if err != nil {
		return "", "", err
	}
	path = req.Request.URL.Path
	values := make(url.Values)
	values.Set(n.scope.ParamName(), namespace)
	query = values.Encode()
	return path, query, nil
}

// ObjectName returns the name and namespace set on the object, or an error if the
// name cannot be returned.
// TODO: distinguish between objects with name/namespace and without via a specific error.
func (n legacyScopeNaming) ObjectName(obj runtime.Object) (namespace, name string, err error) {
	name, err = n.SelfLinker.Name(obj)
	if err != nil {
		return "", "", err
	}
	namespace, err = n.SelfLinker.Namespace(obj)
	if err != nil {
		return "", "", err
	}
	return namespace, name, err
}

// This magic incantation returns *ptrToObject for an arbitrary pointer
func indirectArbitraryPointer(ptrToObject interface{}) interface{} {
	return reflect.Indirect(reflect.ValueOf(ptrToObject)).Interface()
}

func appendIf(actions []action, a action, shouldAppend bool) []action {
	if shouldAppend {
		actions = append(actions, a)
	}
	return actions
}

// Wraps a http.Handler function inside a restful.RouteFunction
func routeFunction(handler http.Handler) restful.RouteFunction {
	return func(restReq *restful.Request, restResp *restful.Response) {
		handler.ServeHTTP(restResp.ResponseWriter, restReq.Request)
	}
}

func addProxyRoute(ws *restful.WebService, method string, prefix string, path string, proxyHandler http.Handler, kind, resource string, params []*restful.Parameter) {
	proxyRoute := ws.Method(method).Path(path).To(routeFunction(proxyHandler)).
		Filter(monitorFilter("PROXY", resource)).
		Doc("proxy " + method + " requests to " + kind).
		Operation("proxy" + method + kind).
		Produces("*/*").
		Consumes("*/*").
		Writes("string")
	addParams(proxyRoute, params)
	ws.Route(proxyRoute)
}

func addParams(route *restful.RouteBuilder, params []*restful.Parameter) {
	for _, param := range params {
		route.Param(param)
	}
}

// addObjectParams converts a runtime.Object into a set of go-restful Param() definitions on the route.
// The object must be a pointer to a struct; only fields at the top level of the struct that are not
// themselves interfaces or structs are used; only fields with a json tag that is non empty (the standard
// Go JSON behavior for omitting a field) become query parameters. The name of the query parameter is
// the JSON field name. If a description struct tag is set on the field, that description is used on the
// query parameter. In essence, it converts a standard JSON top level object into a query param schema.
func addObjectParams(ws *restful.WebService, route *restful.RouteBuilder, obj interface{}) error {
	sv, err := conversion.EnforcePtr(obj)
	if err != nil {
		return err
	}
	st := sv.Type()
	switch st.Kind() {
	case reflect.Struct:
		for i := 0; i < st.NumField(); i++ {
			name := st.Field(i).Name
			sf, ok := st.FieldByName(name)
			if !ok {
				continue
			}
			switch sf.Type.Kind() {
			case reflect.Interface, reflect.Struct:
			default:
				jsonTag := sf.Tag.Get("json")
				if len(jsonTag) == 0 {
					continue
				}
				jsonName := strings.SplitN(jsonTag, ",", 2)[0]
				if len(jsonName) == 0 {
					continue
				}
				desc := sf.Tag.Get("description")
				route.Param(ws.QueryParameter(jsonName, desc).DataType(typeToJSON(sf.Type.Name())))
			}
		}
	}
	return nil
}

// TODO: this is incomplete, expand as needed.
// Convert the name of a golang type to the name of a JSON type
func typeToJSON(typeName string) string {
	switch typeName {
	case "bool":
		return "boolean"
	case "uint8", "int", "int32", "int64", "uint32", "uint64":
		return "integer"
	case "byte":
		return "string"
	case "float64", "float32":
		return "number"
	case "util.Time":
		return "string"
	default:
		return typeName
	}
}

// defaultStorageMetadata provides default answers to rest.StorageMetadata.
type defaultStorageMetadata struct{}

// defaultStorageMetadata implements rest.StorageMetadata
var _ rest.StorageMetadata = defaultStorageMetadata{}

func (defaultStorageMetadata) ProducesMIMETypes(verb string) []string {
	return nil
}