etcd/contrib/lock/storage/storage.go
2021-04-06 15:21:01 -04:00

102 lines
2.5 KiB
Go

// Copyright 2020 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 main
import (
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
"os"
"strings"
)
type value struct {
val string
version int64
}
var data = make(map[string]*value)
type request struct {
Op string `json:"op"`
Key string `json:"key"`
Val string `json:"val"`
Version int64 `json:"version"`
}
type response struct {
Val string `json:"val"`
Version int64 `json:"version"`
Err string `json:"err"`
}
func writeResponse(resp response, w http.ResponseWriter) {
wBytes, err := json.Marshal(resp)
if err != nil {
fmt.Printf("failed to marshal json: %s\n", err)
os.Exit(1)
}
_, err = w.Write(wBytes)
if err != nil {
fmt.Printf("failed to write a response: %s\n", err)
os.Exit(1)
}
}
func handler(w http.ResponseWriter, r *http.Request) {
rBytes, err := ioutil.ReadAll(r.Body)
if err != nil {
fmt.Printf("failed to read http request: %s\n", err)
os.Exit(1)
}
var req request
err = json.Unmarshal(rBytes, &req)
if err != nil {
fmt.Printf("failed to unmarshal json: %s\n", err)
os.Exit(1)
}
if strings.Compare(req.Op, "read") == 0 {
if val, ok := data[req.Key]; ok {
writeResponse(response{val.val, val.version, ""}, w)
} else {
writeResponse(response{"", -1, "key not found"}, w)
}
} else if strings.Compare(req.Op, "write") == 0 {
if val, ok := data[req.Key]; ok {
if req.Version != val.version {
writeResponse(response{"", -1, fmt.Sprintf("given version (%d) is different from the existing version (%d)", req.Version, val.version)}, w)
} else {
data[req.Key].val = req.Val
data[req.Key].version = req.Version
writeResponse(response{req.Val, req.Version, ""}, w)
}
} else {
data[req.Key] = &value{req.Val, req.Version}
writeResponse(response{req.Val, req.Version, ""}, w)
}
} else {
fmt.Printf("unknown op: %s\n", req.Op)
return
}
}
func main() {
http.HandleFunc("/", handler)
http.ListenAndServe(":8080", nil)
}