1 files changed, 227 insertions, 0 deletions
diff --git a/vendor/github.com/golang/groupcache/http.go b/vendor/github.com/golang/groupcache/http.go
new file mode 100644
index 000000000..14eb345a8
--- /dev/null
+++ b/vendor/github.com/golang/groupcache/http.go
@@ -0,0 +1,227 @@
+/*
+Copyright 2013 Google Inc.
+
+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 groupcache
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+	"sync"
+
+	"github.com/golang/groupcache/consistenthash"
+	pb "github.com/golang/groupcache/groupcachepb"
+	"github.com/golang/protobuf/proto"
+)
+
+const defaultBasePath = "/_groupcache/"
+
+const defaultReplicas = 50
+
+// HTTPPool implements PeerPicker for a pool of HTTP peers.
+type HTTPPool struct {
+	// Context optionally specifies a context for the server to use when it
+	// receives a request.
+	// If nil, the server uses a nil Context.
+	Context func(*http.Request) Context
+
+	// Transport optionally specifies an http.RoundTripper for the client
+	// to use when it makes a request.
+	// If nil, the client uses http.DefaultTransport.
+	Transport func(Context) http.RoundTripper
+
+	// this peer's base URL, e.g. "https://example.net:8000"
+	self string
+
+	// opts specifies the options.
+	opts HTTPPoolOptions
+
+	mu          sync.Mutex // guards peers and httpGetters
+	peers       *consistenthash.Map
+	httpGetters map[string]*httpGetter // keyed by e.g. "http://10.0.0.2:8008"
+}
+
+// HTTPPoolOptions are the configurations of a HTTPPool.
+type HTTPPoolOptions struct {
+	// BasePath specifies the HTTP path that will serve groupcache requests.
+	// If blank, it defaults to "/_groupcache/".
+	BasePath string
+
+	// Replicas specifies the number of key replicas on the consistent hash.
+	// If blank, it defaults to 50.
+	Replicas int
+
+	// HashFn specifies the hash function of the consistent hash.
+	// If blank, it defaults to crc32.ChecksumIEEE.
+	HashFn consistenthash.Hash
+}
+
+// NewHTTPPool initializes an HTTP pool of peers, and registers itself as a PeerPicker.
+// For convenience, it also registers itself as an http.Handler with http.DefaultServeMux.
+// The self argument be a valid base URL that points to the current server,
+// for example "http://example.net:8000".
+func NewHTTPPool(self string) *HTTPPool {
+	p := NewHTTPPoolOpts(self, nil)
+	http.Handle(p.opts.BasePath, p)
+	return p
+}
+
+var httpPoolMade bool
+
+// NewHTTPPoolOpts initializes an HTTP pool of peers with the given options.
+// Unlike NewHTTPPool, this function does not register the created pool as an HTTP handler.
+// The returned *HTTPPool implements http.Handler and must be registered using http.Handle.
+func NewHTTPPoolOpts(self string, o *HTTPPoolOptions) *HTTPPool {
+	if httpPoolMade {
+		panic("groupcache: NewHTTPPool must be called only once")
+	}
+	httpPoolMade = true
+
+	p := &HTTPPool{
+		self:        self,
+		httpGetters: make(map[string]*httpGetter),
+	}
+	if o != nil {
+		p.opts = *o
+	}
+	if p.opts.BasePath == "" {
+		p.opts.BasePath = defaultBasePath
+	}
+	if p.opts.Replicas == 0 {
+		p.opts.Replicas = defaultReplicas
+	}
+	p.peers = consistenthash.New(p.opts.Replicas, p.opts.HashFn)
+
+	RegisterPeerPicker(func() PeerPicker { return p })
+	return p
+}
+
+// Set updates the pool's list of peers.
+// Each peer value should be a valid base URL,
+// for example "http://example.net:8000".
+func (p *HTTPPool) Set(peers ...string) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.peers = consistenthash.New(p.opts.Replicas, p.opts.HashFn)
+	p.peers.Add(peers...)
+	p.httpGetters = make(map[string]*httpGetter, len(peers))
+	for _, peer := range peers {
+		p.httpGetters[peer] = &httpGetter{transport: p.Transport, baseURL: peer + p.opts.BasePath}
+	}
+}
+
+func (p *HTTPPool) PickPeer(key string) (ProtoGetter, bool) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.peers.IsEmpty() {
+		return nil, false
+	}
+	if peer := p.peers.Get(key); peer != p.self {
+		return p.httpGetters[peer], true
+	}
+	return nil, false
+}
+
+func (p *HTTPPool) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	// Parse request.
+	if !strings.HasPrefix(r.URL.Path, p.opts.BasePath) {
+		panic("HTTPPool serving unexpected path: " + r.URL.Path)
+	}
+	parts := strings.SplitN(r.URL.Path[len(p.opts.BasePath):], "/", 2)
+	if len(parts) != 2 {
+		http.Error(w, "bad request", http.StatusBadRequest)
+		return
+	}
+	groupName := parts[0]
+	key := parts[1]
+
+	// Fetch the value for this group/key.
+	group := GetGroup(groupName)
+	if group == nil {
+		http.Error(w, "no such group: "+groupName, http.StatusNotFound)
+		return
+	}
+	var ctx Context
+	if p.Context != nil {
+		ctx = p.Context(r)
+	}
+
+	group.Stats.ServerRequests.Add(1)
+	var value []byte
+	err := group.Get(ctx, key, AllocatingByteSliceSink(&value))
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	// Write the value to the response body as a proto message.
+	body, err := proto.Marshal(&pb.GetResponse{Value: value})
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	w.Header().Set("Content-Type", "application/x-protobuf")
+	w.Write(body)
+}
+
+type httpGetter struct {
+	transport func(Context) http.RoundTripper
+	baseURL   string
+}
+
+var bufferPool = sync.Pool{
+	New: func() interface{} { return new(bytes.Buffer) },
+}
+
+func (h *httpGetter) Get(context Context, in *pb.GetRequest, out *pb.GetResponse) error {
+	u := fmt.Sprintf(
+		"%v%v/%v",
+		h.baseURL,
+		url.QueryEscape(in.GetGroup()),
+		url.QueryEscape(in.GetKey()),
+	)
+	req, err := http.NewRequest("GET", u, nil)
+	if err != nil {
+		return err
+	}
+	tr := http.DefaultTransport
+	if h.transport != nil {
+		tr = h.transport(context)
+	}
+	res, err := tr.RoundTrip(req)
+	if err != nil {
+		return err
+	}
+	defer res.Body.Close()
+	if res.StatusCode != http.StatusOK {
+		return fmt.Errorf("server returned: %v", res.Status)
+	}
+	b := bufferPool.Get().(*bytes.Buffer)
+	b.Reset()
+	defer bufferPool.Put(b)
+	_, err = io.Copy(b, res.Body)
+	if err != nil {
+		return fmt.Errorf("reading response body: %v", err)
+	}
+	err = proto.Unmarshal(b.Bytes(), out)
+	if err != nil {
+		return fmt.Errorf("decoding response body: %v", err)
+	}
+	return nil
+}