reconcile merge

Signed-off-by: Huamin Chen <hchen@redhat.com>

vendor/k8s.io/client-go/discovery/cached_discovery.go

@@ -0,0 +1,295 @@
+/*
+Copyright 2016 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 discovery
+
+import (
+	"errors"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+
+	"github.com/googleapis/gnostic/OpenAPIv2"
+	"k8s.io/klog"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/version"
+	"k8s.io/client-go/kubernetes/scheme"
+	restclient "k8s.io/client-go/rest"
+)
+
+// CachedDiscoveryClient implements the functions that discovery server-supported API groups,
+// versions and resources.
+type CachedDiscoveryClient struct {
+	delegate DiscoveryInterface
+
+	// cacheDirectory is the directory where discovery docs are held.  It must be unique per host:port combination to work well.
+	cacheDirectory string
+
+	// ttl is how long the cache should be considered valid
+	ttl time.Duration
+
+	// mutex protects the variables below
+	mutex sync.Mutex
+
+	// ourFiles are all filenames of cache files created by this process
+	ourFiles map[string]struct{}
+	// invalidated is true if all cache files should be ignored that are not ours (e.g. after Invalidate() was called)
+	invalidated bool
+	// fresh is true if all used cache files were ours
+	fresh bool
+}
+
+var _ CachedDiscoveryInterface = &CachedDiscoveryClient{}
+
+// ServerResourcesForGroupVersion returns the supported resources for a group and version.
+func (d *CachedDiscoveryClient) ServerResourcesForGroupVersion(groupVersion string) (*metav1.APIResourceList, error) {
+	filename := filepath.Join(d.cacheDirectory, groupVersion, "serverresources.json")
+	cachedBytes, err := d.getCachedFile(filename)
+	// don't fail on errors, we either don't have a file or won't be able to run the cached check. Either way we can fallback.
+	if err == nil {
+		cachedResources := &metav1.APIResourceList{}
+		if err := runtime.DecodeInto(scheme.Codecs.UniversalDecoder(), cachedBytes, cachedResources); err == nil {
+			klog.V(10).Infof("returning cached discovery info from %v", filename)
+			return cachedResources, nil
+		}
+	}
+
+	liveResources, err := d.delegate.ServerResourcesForGroupVersion(groupVersion)
+	if err != nil {
+		klog.V(3).Infof("skipped caching discovery info due to %v", err)
+		return liveResources, err
+	}
+	if liveResources == nil || len(liveResources.APIResources) == 0 {
+		klog.V(3).Infof("skipped caching discovery info, no resources found")
+		return liveResources, err
+	}
+
+	if err := d.writeCachedFile(filename, liveResources); err != nil {
+		klog.V(1).Infof("failed to write cache to %v due to %v", filename, err)
+	}
+
+	return liveResources, nil
+}
+
+// ServerResources returns the supported resources for all groups and versions.
+func (d *CachedDiscoveryClient) ServerResources() ([]*metav1.APIResourceList, error) {
+	return ServerResources(d)
+}
+
+// ServerGroups returns the supported groups, with information like supported versions and the
+// preferred version.
+func (d *CachedDiscoveryClient) ServerGroups() (*metav1.APIGroupList, error) {
+	filename := filepath.Join(d.cacheDirectory, "servergroups.json")
+	cachedBytes, err := d.getCachedFile(filename)
+	// don't fail on errors, we either don't have a file or won't be able to run the cached check. Either way we can fallback.
+	if err == nil {
+		cachedGroups := &metav1.APIGroupList{}
+		if err := runtime.DecodeInto(scheme.Codecs.UniversalDecoder(), cachedBytes, cachedGroups); err == nil {
+			klog.V(10).Infof("returning cached discovery info from %v", filename)
+			return cachedGroups, nil
+		}
+	}
+
+	liveGroups, err := d.delegate.ServerGroups()
+	if err != nil {
+		klog.V(3).Infof("skipped caching discovery info due to %v", err)
+		return liveGroups, err
+	}
+	if liveGroups == nil || len(liveGroups.Groups) == 0 {
+		klog.V(3).Infof("skipped caching discovery info, no groups found")
+		return liveGroups, err
+	}
+
+	if err := d.writeCachedFile(filename, liveGroups); err != nil {
+		klog.V(1).Infof("failed to write cache to %v due to %v", filename, err)
+	}
+
+	return liveGroups, nil
+}
+
+func (d *CachedDiscoveryClient) getCachedFile(filename string) ([]byte, error) {
+	// after invalidation ignore cache files not created by this process
+	d.mutex.Lock()
+	_, ourFile := d.ourFiles[filename]
+	if d.invalidated && !ourFile {
+		d.mutex.Unlock()
+		return nil, errors.New("cache invalidated")
+	}
+	d.mutex.Unlock()
+
+	file, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	fileInfo, err := file.Stat()
+	if err != nil {
+		return nil, err
+	}
+
+	if time.Now().After(fileInfo.ModTime().Add(d.ttl)) {
+		return nil, errors.New("cache expired")
+	}
+
+	// the cache is present and its valid.  Try to read and use it.
+	cachedBytes, err := ioutil.ReadAll(file)
+	if err != nil {
+		return nil, err
+	}
+
+	d.mutex.Lock()
+	defer d.mutex.Unlock()
+	d.fresh = d.fresh && ourFile
+
+	return cachedBytes, nil
+}
+
+func (d *CachedDiscoveryClient) writeCachedFile(filename string, obj runtime.Object) error {
+	if err := os.MkdirAll(filepath.Dir(filename), 0755); err != nil {
+		return err
+	}
+
+	bytes, err := runtime.Encode(scheme.Codecs.LegacyCodec(), obj)
+	if err != nil {
+		return err
+	}
+
+	f, err := ioutil.TempFile(filepath.Dir(filename), filepath.Base(filename)+".")
+	if err != nil {
+		return err
+	}
+	defer os.Remove(f.Name())
+	_, err = f.Write(bytes)
+	if err != nil {
+		return err
+	}
+
+	err = os.Chmod(f.Name(), 0755)
+	if err != nil {
+		return err
+	}
+
+	name := f.Name()
+	err = f.Close()
+	if err != nil {
+		return err
+	}
+
+	// atomic rename
+	d.mutex.Lock()
+	defer d.mutex.Unlock()
+	err = os.Rename(name, filename)
+	if err == nil {
+		d.ourFiles[filename] = struct{}{}
+	}
+	return err
+}
+
+// RESTClient returns a RESTClient that is used to communicate with API server
+// by this client implementation.
+func (d *CachedDiscoveryClient) RESTClient() restclient.Interface {
+	return d.delegate.RESTClient()
+}
+
+// ServerPreferredResources returns the supported resources with the version preferred by the
+// server.
+func (d *CachedDiscoveryClient) ServerPreferredResources() ([]*metav1.APIResourceList, error) {
+	return ServerPreferredResources(d)
+}
+
+// ServerPreferredNamespacedResources returns the supported namespaced resources with the
+// version preferred by the server.
+func (d *CachedDiscoveryClient) ServerPreferredNamespacedResources() ([]*metav1.APIResourceList, error) {
+	return ServerPreferredNamespacedResources(d)
+}
+
+// ServerVersion retrieves and parses the server's version (git version).
+func (d *CachedDiscoveryClient) ServerVersion() (*version.Info, error) {
+	return d.delegate.ServerVersion()
+}
+
+// OpenAPISchema retrieves and parses the swagger API schema the server supports.
+func (d *CachedDiscoveryClient) OpenAPISchema() (*openapi_v2.Document, error) {
+	return d.delegate.OpenAPISchema()
+}
+
+// Fresh is supposed to tell the caller whether or not to retry if the cache
+// fails to find something (false = retry, true = no need to retry).
+func (d *CachedDiscoveryClient) Fresh() bool {
+	d.mutex.Lock()
+	defer d.mutex.Unlock()
+
+	return d.fresh
+}
+
+// Invalidate enforces that no cached data is used in the future that is older than the current time.
+func (d *CachedDiscoveryClient) Invalidate() {
+	d.mutex.Lock()
+	defer d.mutex.Unlock()
+
+	d.ourFiles = map[string]struct{}{}
+	d.fresh = true
+	d.invalidated = true
+}
+
+// NewCachedDiscoveryClientForConfig creates a new DiscoveryClient for the given config, and wraps
+// the created client in a CachedDiscoveryClient. The provided configuration is updated with a
+// custom transport that understands cache responses.
+// We receive two distinct cache directories for now, in order to preserve old behavior
+// which makes use of the --cache-dir flag value for storing cache data from the CacheRoundTripper,
+// and makes use of the hardcoded destination (~/.kube/cache/discovery/...) for storing
+// CachedDiscoveryClient cache data. If httpCacheDir is empty, the restconfig's transport will not
+// be updated with a roundtripper that understands cache responses.
+// If discoveryCacheDir is empty, cached server resource data will be looked up in the current directory.
+// TODO(juanvallejo): the value of "--cache-dir" should be honored. Consolidate discoveryCacheDir with httpCacheDir
+// so that server resources and http-cache data are stored in the same location, provided via config flags.
+func NewCachedDiscoveryClientForConfig(config *restclient.Config, discoveryCacheDir, httpCacheDir string, ttl time.Duration) (*CachedDiscoveryClient, error) {
+	if len(httpCacheDir) > 0 {
+		// update the given restconfig with a custom roundtripper that
+		// understands how to handle cache responses.
+		wt := config.WrapTransport
+		config.WrapTransport = func(rt http.RoundTripper) http.RoundTripper {
+			if wt != nil {
+				rt = wt(rt)
+			}
+			return newCacheRoundTripper(httpCacheDir, rt)
+		}
+	}
+
+	discoveryClient, err := NewDiscoveryClientForConfig(config)
+	if err != nil {
+		return nil, err
+	}
+
+	return newCachedDiscoveryClient(discoveryClient, discoveryCacheDir, ttl), nil
+}
+
+// NewCachedDiscoveryClient creates a new DiscoveryClient.  cacheDirectory is the directory where discovery docs are held.  It must be unique per host:port combination to work well.
+func newCachedDiscoveryClient(delegate DiscoveryInterface, cacheDirectory string, ttl time.Duration) *CachedDiscoveryClient {
+	return &CachedDiscoveryClient{
+		delegate:       delegate,
+		cacheDirectory: cacheDirectory,
+		ttl:            ttl,
+		ourFiles:       map[string]struct{}{},
+		fresh:          true,
+	}
+}