LevelDB+Golang Hello World

leveldb.go

package main

import (
	"bufio"
	"fmt"
	"log"
	"os"
	"strings"

	"github.com/syndtr/goleveldb/leveldb"
)

func main() {
	db, err := leveldb.OpenFile("kv.db", nil)
	if err != nil {
		log.Fatalf("failed to open/create database: %w\n", err)
	}
	defer db.Close()

	s := bufio.NewScanner(os.Stdin)
	for {
		fmt.Print("> ")
		if !s.Scan() {
			break
		}

		tokens := strings.Split(s.Text(), " ")
		if len(tokens) < 2 || (tokens[0] == "put" && len(tokens) != 3) {
			fmt.Println("invalid input")
			continue
		}

		switch tokens[0] {
		case "put":
			err := db.Put([]byte(tokens[1]), []byte(tokens[2]), nil)
			if err != nil {
				fmt.Println("failed to put data:", err)
				continue
			}

		case "get":
			value, err := db.Get([]byte(tokens[1]), nil)
			if err != nil {
				fmt.Println("failed to get value:", err)
				continue
			}
			fmt.Println(string(value))
		}
	}
}