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main.go
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main.go
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package main
import (
"bufio"
"flag"
"fmt"
"log"
"os"
"strings"
"github.com/dgraph-io/badger"
)
func main() {
path := flag.String("d", "../db", "path containing the badger data")
flag.Parse()
bdb, err := badger.Open(badger.DefaultOptions(*path).WithLogger(nil))
if err != nil {
log.Fatal(err)
}
db := database{bdb}
defer db.close()
s := bufio.NewScanner(os.Stdin)
for fmt.Printf("> "); s.Scan(); fmt.Printf("> ") {
line := strings.TrimSpace(s.Text())
fields := strings.Fields(line)
if len(fields) == 0 {
continue
}
var err error
switch first := fields[0]; first {
case "bye", "exit", "quit":
fmt.Println("good bye")
return
case "set":
err = db.set(fields)
case "get":
err = db.get(fields)
case "delete":
err = db.delete(fields)
case "ls":
err = db.list(fields)
default:
err = fmt.Errorf("unknown command %q", first)
}
if err != nil {
fmt.Fprintln(os.Stderr, err)
}
}
if err := s.Err(); err != nil {
log.Fatalf("reading from stdin: %v", err)
}
}
type database struct{ db *badger.DB }
func (db database) close() {
if err := db.db.Close(); err != nil {
log.Fatal(err)
}
}
func (db database) get(args []string) error {
if len(args) != 2 {
return fmt.Errorf("get expects one key as parameter: 'get key'")
}
key := args[1]
var val string
err := db.db.View(func(txn *badger.Txn) error {
item, err := txn.Get([]byte(key))
if err != nil {
return err
}
return item.Value(func(b []byte) error { val = string(b); return nil })
})
if err != nil {
return err
}
fmt.Println(val)
return nil
}
func (db database) set(args []string) error {
if len(args) != 3 {
return fmt.Errorf("set expects one key and one value as parameters: 'set key value'")
}
key := args[1]
val := args[2]
return db.db.Update(func(txn *badger.Txn) error {
return txn.Set([]byte(key), []byte(val))
})
}
func (db database) delete(args []string) error {
if len(args) != 2 {
return fmt.Errorf("delete expects one key as parameter: 'delete key'")
}
key := args[1]
return db.db.Update(func(txn *badger.Txn) error {
return txn.Delete([]byte(key))
})
}
func (db database) list(args []string) error {
if len(args) != 1 {
return fmt.Errorf("ls doesn't expect any parameters")
}
return db.db.View(func(txn *badger.Txn) error {
it := txn.NewIterator(badger.IteratorOptions{})
defer it.Close()
for it.Rewind(); it.Valid(); it.Next() {
fmt.Printf("%s\n", it.Item().Key())
}
return nil
})
}