simple badger usage

badgerdb.go

package main

import (
	"encoding/binary"
	"fmt"
	"sync"

	"github.com/dgraph-io/badger/v4"
)

func main() {
	opts := badger.DefaultOptions("/tmp/badger")
	opts.Logger = nil
	db, err := badger.Open(opts)
	if err != nil {
		panic(err)
	}
	defer db.Close()

	if err := db.DropAll(); err != nil {
		panic(err)
	}

	func() {
		txn := db.NewTransaction(true)
		defer txn.Discard()
		if err := txn.Set([]byte("a"), []byte("0")); err != nil {
			panic(err)
		}
		if err := txn.Commit(); err != nil {
			panic(err)
		}
	}()

	if err := db.View(func(txn *badger.Txn) error {
		item, err := txn.Get([]byte("a"))
		if err != nil {
			panic(err)
		}
		return item.Value(func(val []byte) error {
			fmt.Println("get", string(val))
			return nil
		})
	}); err != nil {
		panic(err)
	}

	func() {
		txn := db.NewTransaction(false)
		defer txn.Discard()

		it := txn.NewIterator(badger.DefaultIteratorOptions)
		defer it.Close()
		it.Rewind()

		if it.Valid() {
			i := it.Item()
			k := i.Key()
			fmt.Println("iterator", string(k))
		} else {
			fmt.Println("no key")
		}
	}()

	if err := db.DropAll(); err != nil {
		panic(err)
	}
}