Golang badger db using GOB to serialise object data into badger fields

main.go

/*
 *
 * Golang  badger db using GOB to serialize object data into badger fields
 *
 * Golang has its very own serializer / deserializer - Go Object (gob) so why not use it where data passed is entirely within a Go
 * application ?
 *
 * JSON or some other text based solution could be used but gob might be faster.
 *
 * A gob encoder accepts the type bytes.Buffer to encode data to, so to write this to Badger, which accepts the type byte
 * this is converted using bytes.Buffer Bytes function to convert it.
 *
 * Subssequently to read back the type bytes into a gob decoder, bytes.NewReader converts type bytes back to bytes.Buffer for a
 * gob decoder to de-serialize the data.
 *
 */

package main

import (
	"bytes"
	"encoding/gob"
	"fmt"
	"log"

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

type Student struct {
	Name string
	Age  int32
}

func main() {

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

	studentEncode := Student{Name: "Peter", Age: 36}

	var b bytes.Buffer
	e := gob.NewEncoder(&b)
	if err := e.Encode(studentEncode); err != nil {
		panic(err)
	}
	err = db.Update(func(txn *badger.Txn) error {
		err := txn.Set([]byte("answer"), b.Bytes())
		return err
	})

	if err != nil {
		fmt.Printf("ERROR saving to badger db : %s\n", err)
	}
	key := "answer"
	err = db.View(func(txn *badger.Txn) error {
		item, err := txn.Get([]byte(key))
		if err != nil {
			return err
		}
		val, err := item.ValueCopy(nil)

		if err != nil {
			return err
		}

		var studentDecode Student
		d := gob.NewDecoder(bytes.NewReader(val))
		if err := d.Decode(&studentDecode); err != nil {
			panic(err)
		}

		log.Printf("Decoded Struct from badger : name [%s] age [%d]\n", studentDecode.Name, studentDecode.Age)

		return nil
	})

}

apparently there are breaking changes to the opts and Item.value functionality from 1.6.0 onwards, updated this to use 'ValueCopy' and new DefaultOptions with just a string containing the path to the DB, in this case, /tmp - change it to be where it is needed to be so long as it exists and is writable. The badger directory gets created by badger itself if it is not already there