server: Move server files to 'server' directory.

26  git mv mvcc wal auth etcdserver etcdmain proxy embed/ lease/ server
   36  git mv go.mod go.sum server

server/proxy/httpproxy/proxy.go

@@ -0,0 +1,121 @@
+// Copyright 2015 The etcd 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 httpproxy
+
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+	"time"
+
+	"go.uber.org/zap"
+	"golang.org/x/net/http2"
+)
+
+const (
+	// DefaultMaxIdleConnsPerHost indicates the default maximum idle connection
+	// count maintained between proxy and each member. We set it to 128 to
+	// let proxy handle 128 concurrent requests in long term smoothly.
+	// If the number of concurrent requests is bigger than this value,
+	// proxy needs to create one new connection when handling each request in
+	// the delta, which is bad because the creation consumes resource and
+	// may eat up ephemeral ports.
+	DefaultMaxIdleConnsPerHost = 128
+)
+
+// GetProxyURLs is a function which should return the current set of URLs to
+// which client requests should be proxied. This function will be queried
+// periodically by the proxy Handler to refresh the set of available
+// backends.
+type GetProxyURLs func() []string
+
+// NewHandler creates a new HTTP handler, listening on the given transport,
+// which will proxy requests to an etcd cluster.
+// The handler will periodically update its view of the cluster.
+func NewHandler(lg *zap.Logger, t *http.Transport, urlsFunc GetProxyURLs, failureWait time.Duration, refreshInterval time.Duration) http.Handler {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	if t.TLSClientConfig != nil {
+		// Enable http2, see Issue 5033.
+		err := http2.ConfigureTransport(t)
+		if err != nil {
+			lg.Info("Error enabling Transport HTTP/2 support", zap.Error(err))
+		}
+	}
+
+	p := &reverseProxy{
+		lg:        lg,
+		director:  newDirector(lg, urlsFunc, failureWait, refreshInterval),
+		transport: t,
+	}
+
+	mux := http.NewServeMux()
+	mux.Handle("/", p)
+	mux.HandleFunc("/v2/config/local/proxy", p.configHandler)
+
+	return mux
+}
+
+// NewReadonlyHandler wraps the given HTTP handler to allow only GET requests
+func NewReadonlyHandler(hdlr http.Handler) http.Handler {
+	readonly := readonlyHandlerFunc(hdlr)
+	return http.HandlerFunc(readonly)
+}
+
+func readonlyHandlerFunc(next http.Handler) func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, req *http.Request) {
+		if req.Method != "GET" {
+			w.WriteHeader(http.StatusNotImplemented)
+			return
+		}
+
+		next.ServeHTTP(w, req)
+	}
+}
+
+func (p *reverseProxy) configHandler(w http.ResponseWriter, r *http.Request) {
+	if !allowMethod(w, r.Method, "GET") {
+		return
+	}
+
+	eps := p.director.endpoints()
+	epstr := make([]string, len(eps))
+	for i, e := range eps {
+		epstr[i] = e.URL.String()
+	}
+
+	proxyConfig := struct {
+		Endpoints []string `json:"endpoints"`
+	}{
+		Endpoints: epstr,
+	}
+
+	json.NewEncoder(w).Encode(proxyConfig)
+}
+
+// allowMethod verifies that the given method is one of the allowed methods,
+// and if not, it writes an error to w.  A boolean is returned indicating
+// whether or not the method is allowed.
+func allowMethod(w http.ResponseWriter, m string, ms ...string) bool {
+	for _, meth := range ms {
+		if m == meth {
+			return true
+		}
+	}
+	w.Header().Set("Allow", strings.Join(ms, ","))
+	http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
+	return false
+}