add leveldb as db

db/leveldb.go

@@ -0,0 +1,55 @@
+package db
+
+import (
+	"github.com/syndtr/goleveldb/leveldb"
+)
+
+// Db is the database with the specified prefix
+type Db struct {
+	ldb    *leveldb.DB
+	prefix []byte
+}
+
+// New creates a new Db database
+func New(path string) (*Db, error) {
+	ldb, err := leveldb.OpenFile(path, nil)
+	if err != nil {
+		return nil, err
+	}
+	return &Db{ldb, []byte{}}, nil
+}
+
+// WithPrefix returns a subdatabase with the specified prefix
+func (db *Db) WithPrefix(prefix []byte) *Db {
+	return &Db{db.ldb, append(db.prefix, prefix...)}
+}
+
+// Put adds the key value to the database
+func (db *Db) Put(key, value []byte) error {
+	err := db.ldb.Put(append(db.prefix, key[:]...), value, nil)
+	return err
+}
+
+// Get retreives a value from the database for a given key
+func (db *Db) Get(key []byte) ([]byte, error) {
+	v, err := db.ldb.Get(append(db.prefix, key[:]...), nil)
+	if err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// Iterate iterates over the database
+func (db *Db) Iterate(f func([]byte, []byte)) error {
+	snapshot, err := db.ldb.GetSnapshot()
+	if err != nil {
+		return err
+	}
+	iter := snapshot.NewIterator(nil, nil)
+	for iter.Next() {
+		f(iter.Key(), iter.Value())
+	}
+	iter.Release()
+	err = iter.Error()
+	return err
+}

db/leveldb_test.go

@@ -0,0 +1,53 @@
+package db
+
+import (
+	"io/ioutil"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/syndtr/goleveldb/leveldb/errors"
+)
+
+func TestNew(t *testing.T) {
+	dir, err := ioutil.TempDir("", "db")
+	assert.Nil(t, err)
+	_, err = New(dir)
+	assert.Nil(t, err)
+}
+func TestPutAndGet(t *testing.T) {
+	dir, err := ioutil.TempDir("", "db")
+	assert.Nil(t, err)
+	db, err := New(dir)
+	assert.Nil(t, err)
+
+	k := []byte("test key")
+	v := []byte("test value")
+
+	err = db.Put(k, v)
+	assert.Nil(t, err)
+
+	vg, err := db.Get(k)
+	assert.Nil(t, err)
+	assert.Equal(t, v, vg)
+
+}
+
+func TestPrefix(t *testing.T) {
+	dir, err := ioutil.TempDir("", "db")
+	assert.Nil(t, err)
+	db, err := New(dir)
+	assert.Nil(t, err)
+
+	dbPrefix := db.WithPrefix([]byte("prefix1"))
+
+	err = dbPrefix.Put([]byte("k1"), []byte("v1"))
+	assert.Nil(t, err)
+
+	_, err = db.Get([]byte("k1"))
+	assert.Equal(t, err, errors.ErrNotFound)
+
+	v1, err := dbPrefix.Get([]byte("k1"))
+	assert.Nil(t, err)
+	assert.Equal(t, []byte("v1"), v1)
+}