Initial work on storage package

storage/goleveldb_store.go

@@ -0,0 +1,81 @@
+package storage
+
+import (
+	"strconv"
+
+	"github.com/syndtr/goleveldb/leveldb"
+)
+
+// GoleveldbStore allows storing data into a goleveldb database.
+type GoleveldbStore struct {
+	DB *leveldb.DB
+}
+
+// NewGoleveldbStore creates a new GoleveldbStore using given path to persist
+// data.
+func NewGoleveldbStore(path string) (GoleveldbStore, error) {
+	db, err := leveldb.OpenFile(path, nil)
+	if err != nil {
+		return GoleveldbStore{}, err
+	}
+
+	return GoleveldbStore{DB: db}, nil
+}
+
+// Close underlying goleveldb database.
+func (s *GoleveldbStore) Close() error {
+	return s.DB.Close()
+}
+
+// Get a given key's value.
+func (s *GoleveldbStore) Get(key []byte) ([]byte, error) {
+	value, err := s.DB.Get(key, nil)
+	if err != nil && err.Error() == "leveldb: not found" {
+		return value, nil
+	}
+
+	return value, err
+}
+
+// Set a given key's to the specified value.
+func (s *GoleveldbStore) Set(key []byte, value []byte) error {
+	return s.DB.Put(key, value, nil)
+}
+
+// Delete a given key.
+func (s *GoleveldbStore) Delete(key []byte) error {
+	return s.DB.Delete(key, nil)
+}
+
+// Incr increments a given key (must be numeric-like value)
+func (s *GoleveldbStore) Incr(key []byte) (int, error) {
+	tx, err := s.DB.OpenTransaction()
+	if err != nil {
+		return -1, err
+	}
+
+	value, err := tx.Get(key, nil)
+	if value == nil {
+		value = []byte("0")
+	}
+
+	num, err := strconv.Atoi(string(value))
+	if err != nil {
+		return -1, err
+	}
+
+	num++
+	value = []byte(strconv.Itoa(num))
+
+	err = tx.Put(key, value, nil)
+	if err != nil {
+		return -1, err
+	}
+
+	err = tx.Commit()
+	if err != nil {
+		return -1, err
+	}
+
+	return num, nil
+}

storage/goleveldb_store_test.go

@@ -0,0 +1,167 @@
+package storage
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+	"github.com/syndtr/goleveldb/leveldb"
+)
+
+// Setup Suite
+
+var testDbPath = "./goleveldb_test_data"
+
+var examples = []struct {
+	key   []byte
+	value []byte
+}{
+	{key: []byte("hello"), value: []byte("world")},
+	{key: []byte("foo"), value: []byte("bar")},
+	{key: []byte("wtf"), value: []byte("dude")},
+}
+
+type GoleveldbStoreSuite struct {
+	suite.Suite
+	store Store
+	db    *leveldb.DB
+}
+
+func (s *GoleveldbStoreSuite) Seed() {
+	for _, e := range examples {
+		err := s.db.Put(e.key, e.value, nil)
+		s.Require().Nil(err)
+	}
+}
+
+func (s *GoleveldbStoreSuite) SetupTest() {
+	store, err := NewGoleveldbStore(testDbPath)
+	s.Nil(err)
+	s.store = &store
+	s.db = store.DB
+}
+
+func (s *GoleveldbStoreSuite) TearDownTest() {
+	s.store.Close()
+	os.RemoveAll(testDbPath)
+}
+
+// Tests
+
+func (s *GoleveldbStoreSuite) TestSet() {
+	for _, e := range examples {
+		err := s.store.Set(e.key, e.value)
+		s.Nil(err)
+	}
+
+	for _, e := range examples {
+		result, _ := s.db.Get(e.key, nil)
+		s.Equal(e.value, result)
+	}
+}
+
+func (s *GoleveldbStoreSuite) TestGetExisting() {
+	s.Seed()
+
+	for _, e := range examples {
+		result, err := s.store.Get(e.key)
+		s.Nil(err)
+		s.Equal(e.value, result)
+	}
+}
+
+func (s *GoleveldbStoreSuite) TestGetNonExistant() {
+	result, err := s.store.Get([]byte("does-not-exist"))
+	s.Nil(err)
+	s.Nil(result)
+}
+
+func (s *GoleveldbStoreSuite) TestDeleteExisting() {
+	s.Seed()
+
+	for _, e := range examples {
+		value, _ := s.db.Get(e.key, nil)
+		s.Require().Equal(e.value, value)
+
+		err := s.store.Delete(e.key)
+		s.Nil(err)
+
+		has, _ := s.db.Has(e.key, nil)
+		s.Equal(false, has)
+		result, _ := s.db.Get(e.key, nil)
+		s.Equal([]byte{}, result)
+	}
+}
+
+func (s *GoleveldbStoreSuite) TestDeleteNonExistant() {
+	err := s.store.Delete([]byte("does-not-exist"))
+	s.Nil(err)
+}
+
+func (s *GoleveldbStoreSuite) TestIncrExisting() {
+	key := []byte("my-counter")
+
+	err := s.db.Put(key, []byte("5"), nil)
+	s.Require().Nil(err)
+
+	result, err := s.store.Incr(key)
+	s.Nil(err)
+	s.Equal(6, result)
+}
+
+func (s *GoleveldbStoreSuite) TestIncrNonExistant() {
+	for i := 1; i < 10; i++ {
+		result, err := s.store.Incr([]byte("counter"))
+
+		s.Nil(err)
+		s.Equal(i, result)
+	}
+}
+
+// Run Suite
+
+func TestGoleveldbStoreSuite(t *testing.T) {
+	suite.Run(t, new(GoleveldbStoreSuite))
+}
+
+// Benchmarks
+
+func BenchmarkGet(b *testing.B) {
+	key := []byte("hello")
+	value := []byte("world")
+	store, _ := NewGoleveldbStore(testDbPath)
+	_ = store.Set(key, value)
+
+	for n := 0; n < b.N; n++ {
+		_, _ = store.Get(key)
+	}
+
+	_ = store.Close()
+	_ = os.RemoveAll(testDbPath)
+}
+
+func BenchmarkSet(b *testing.B) {
+	key := []byte("hello")
+	value := []byte("world")
+	store, _ := NewGoleveldbStore(testDbPath)
+	_ = store.Set(key, value)
+
+	for n := 0; n < b.N; n++ {
+		_ = store.Set(append(key, string(n)...), append(value, string(n)...))
+	}
+
+	_ = store.Close()
+	_ = os.RemoveAll(testDbPath)
+}
+
+func BenchmarkIncr(b *testing.B) {
+	key := []byte("incr-benchmark-counter")
+	store, _ := NewGoleveldbStore(testDbPath)
+
+	for n := 0; n < b.N; n++ {
+		_, _ = store.Incr(key)
+	}
+
+	_ = store.Close()
+	_ = os.RemoveAll(testDbPath)
+}

storage/store.go

@@ -0,0 +1,10 @@
+package storage
+
+// Storage defines a standard interface for storage.
+type Store interface {
+	Close() error
+	Get([]byte) ([]byte, error)
+	Set([]byte, []byte) error
+	Delete([]byte) error
+	Incr([]byte) (int, error)
+}