etcd-io__etcd/contrib/raftexample/httpapi.go

// Copyright 2015 CoreOS, 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 main

import (
	"io/ioutil"
	"log"
	"net/http"
	"strconv"
)

// Handler for a http based key-value store backed by raft
type httpKVAPI struct {
	store *kvstore
}

func (h *httpKVAPI) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	key := r.RequestURI
	switch {
	case r.Method == "PUT":
		v, err := ioutil.ReadAll(r.Body)
		if err != nil {
			log.Printf("Failed to read on PUT (%v)\n", err)
			http.Error(w, "Failed on PUT", http.StatusBadRequest)
			return
		}

		h.store.Propose(key, string(v))

		// Optimistic-- no waiting for ack from raft. Value is not yet
		// committed so a subsequent GET on the key may return old value
		w.WriteHeader(http.StatusNoContent)
	case r.Method == "GET":
		if v, ok := h.store.Lookup(key); ok {
			w.Write([]byte(v))
		} else {
			http.Error(w, "Failed to GET", http.StatusNotFound)
		}
	default:
		w.Header().Set("Allow", "PUT")
		w.Header().Add("Allow", "GET")
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
	}
}

// serveHttpKVAPI starts a key-value server with a GET/PUT API and listens.
func serveHttpKVAPI(port int, proposeC chan<- string, commitC <-chan *string, errorC <-chan error) {
	srv := http.Server{
		Addr:    ":" + strconv.Itoa(port),
		Handler: &httpKVAPI{newKVStore(proposeC, commitC, errorC)},
	}
	if err := srv.ListenAndServe(); err != nil {
		log.Fatal(err)
	}
}