example.go

package main

import "os"
import "log"
import "io/ioutil"
import "github.com/szferi/gomdb"

func Set_Key(key, value string) int {
	path, err := ioutil.TempDir("/tmp", "mdb_test")
	if err != nil {
		log.Fatalf("failed to open temp dir")
	}

	err = os.MkdirAll(path, 0770)
	if err != nil {
		log.Fatalf("failed to create path %s", path)
	}

	env, err := mdb.NewEnv()
	if err != nil {
		log.Fatalf("failed create environment")
	}

	err = env.SetMapSize(1048576) // set to defualt
	if err != nil {
		log.Fatalf("Cannot set mapsize: %s", err)
	}

	err = env.Open(path, 0, 0664)
	if err != nil {
		log.Fatalf("failed to open environment: %s", err)
	}

	var txn *mdb.Txn
	txn, err = env.BeginTxn(nil, 0)
	if err != nil {
		log.Fatalf("failed to being transaction: %s", err)
	}

	var dbi mdb.DBI
	dbi, err = txn.DBIOpen(nil, 0)
	if err != nil {
		log.Fatalf("failed to open database: %s", err)
	}

	err = txn.Put(dbi, []byte(key), []byte(value), mdb.NOOVERWRITE)
	if err != nil {
		log.Fatalf("failed write to open database: %s", err)
	}

	err = txn.Commit()
	if err != nil {
		txn.Abort()
		log.Fatalf("failed to commit: %s", err)
	}

	if env.Close() != nil {
		log.Fatalf("failed to close environment")
	}

	return 0
}

func Get_Key(key string) int {
	path, err := ioutil.TempDir("/tmp", "mdb_test")
	if err != nil {
		log.Fatalf("failed to open temp dir")
	}

	env, err := mdb.NewEnv()
	if err != nil {
		log.Fatalf("failed create environment")
	}

	err = env.SetMapSize(1048576) // set to default
	if err != nil {
		log.Fatalf("Cannot set mapsize: %s", err)
	}

	err = env.Open(path, 0, 0664)
	if err != nil {
		// docs state env needs to be closed on failure
		env.Close()
		log.Fatalf("failed to open environment: %s", err)
	}

	var txn *mdb.Txn
	txn, err = env.BeginTxn(nil, 0)
	if err != nil {
		log.Fatalf("failed to being transaction: %s", err)
	}

	var dbi mdb.DBI
	dbi, err = txn.DBIOpen(nil, 0)
	if err != nil {
		log.Fatalf("failed to open database: %s", err)
	}

	var resp []byte
	resp, err = txn.Get(dbi, []byte(key))
	if err != nil {
		log.Fatalf("failed write to open database: %s", err)
	} else {
		log.Printf("Retrieved %s\nfor key: %s", key, string(resp))
	}

	err = txn.Commit()
	if err != nil {
		txn.Abort()
		log.Fatalf("failed to commit: %s", err)
	}

	if env.Close() != nil {
		log.Fatalf("failed to close environment")
	}

	return 0

}

func main() {

	a := Set_Key("Key1", "Value1")
	if a == 0 {
		log.Println("Success: Set Key 1")
	}
	b := Get_Key("Key1")
	if b == 0 {
		log.Println("Success: Get 2")
	}
}