88 lines
2.0 KiB
Go
88 lines
2.0 KiB
Go
// Demos a trivial key-value database backed by a file.
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package main
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import (
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"context"
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"io/ioutil"
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"log"
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"net/http"
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"os"
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"os/signal"
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"strings"
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"syscall"
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)
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func main() {
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if len(os.Args) != 3 {
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log.Fatalf("Usage: %s LISTEN-ADDRESS DATABASE-FILE\n", os.Args[0])
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}
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listenAddr, dbFilename := os.Args[1], os.Args[2]
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db, err := OpenDB(dbFilename)
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if err != nil && os.IsNotExist(err) {
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log.Println("database file does not exist, creating")
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db, err = CreateDB(dbFilename)
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}
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if err != nil {
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log.Fatalln(err)
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}
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http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
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if _, ok := r.URL.Query()["checkpoint"]; ok && r.Method == "GET" {
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if err := db.Checkpoint(); err != nil {
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w.WriteHeader(http.StatusInternalServerError)
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}
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return
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}
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byteValue, err := ioutil.ReadAll(r.Body)
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if err != nil {
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w.WriteHeader(http.StatusInternalServerError)
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return
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}
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key, value := strings.TrimPrefix(r.URL.Path, "/"), string(byteValue)
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switch r.Method {
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case "GET":
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if value, ok, err := db.Get(key); err != nil {
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w.WriteHeader(http.StatusInternalServerError)
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} else if ok {
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w.WriteHeader(http.StatusOK)
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w.Write([]byte(value))
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} else {
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w.WriteHeader(http.StatusNotFound)
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}
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case "PUT":
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if err := db.Put(key, value); err != nil {
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w.WriteHeader(http.StatusInternalServerError)
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}
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case "DELETE":
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if err := db.Delete(key); err != nil {
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w.WriteHeader(http.StatusInternalServerError)
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}
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default:
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w.WriteHeader(http.StatusMethodNotAllowed)
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}
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})
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server := &http.Server{Addr: listenAddr}
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errs := make(chan error, 1)
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go func() { errs <- server.ListenAndServe() }()
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sig := make(chan os.Signal)
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signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM)
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select {
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case <-sig:
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case err := <-errs:
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log.Println(err)
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}
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// For simplicity, we'll wait for everything to finish, including snapshots.
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if err := server.Shutdown(context.Background()); err != nil {
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log.Fatalln(err)
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}
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if err := db.Close(); err != nil {
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log.Fatalln(err)
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}
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}
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