initial commit

pkg/store/boltstore.go

@@ -0,0 +1,140 @@
+// Copyright (C) 2022 Marius Schellenberger
+
+package store
+
+import (
+	"encoding/json"
+	"io"
+
+	bolt "go.etcd.io/bbolt"
+)
+
+const (
+	defaultBoltBucket = "default"
+	fileMode          = 0o600
+)
+
+type BoltStore struct {
+	Marshaler
+	db *bolt.DB
+}
+
+func NewBoltStore(file string, m Marshaler) (Store, error) {
+	if m == nil {
+		m = NewGOB()
+	}
+	db, err := bolt.Open(file, fileMode, nil)
+	if err != nil {
+		return nil, err
+	}
+	if err := db.Update(func(tx *bolt.Tx) (err error) {
+		_, err = tx.CreateBucketIfNotExists([]byte(defaultBoltBucket))
+		return
+	}); err != nil {
+		return nil, err
+	}
+	return &BoltStore{m, db}, nil
+}
+
+type dump struct {
+	K string `json:"k"`
+	V []byte `json:"v"`
+}
+
+func (bs *BoltStore) Dump(w io.Writer) (err error) {
+	if w == nil {
+		return ErrWriterIsNil
+	}
+	var d []dump
+	err = bs.ForEach(func(k string, v []byte) error {
+		b := make([]byte, len(v))
+		copy(b, v)
+		d = append(d, dump{k, b})
+		return nil
+	})
+	if err != nil {
+		return
+	}
+	return json.NewEncoder(w).Encode(d)
+}
+
+func (bs *BoltStore) Restore(r io.Reader) (err error) {
+	if r == nil {
+		return ErrReaderIsNil
+	}
+	var d []dump
+	err = json.NewDecoder(r).Decode(&d)
+	if err != nil {
+		return
+	}
+	if err = bs.db.Update(func(tx *bolt.Tx) (err error) {
+		if err = tx.DeleteBucket([]byte(defaultBoltBucket)); err != nil {
+			return
+		}
+		_, err = tx.CreateBucket([]byte(defaultBoltBucket))
+		return
+	}); err != nil {
+		return
+	}
+	return bs.db.Update(func(tx *bolt.Tx) (err error) {
+		b := tx.Bucket([]byte(defaultBoltBucket))
+		for _, v := range d {
+			b.Put([]byte(v.K), v.V)
+		}
+		return nil
+	})
+}
+
+func (bs *BoltStore) Get(key string, v interface{}) (err error) {
+	err = bs.db.View(func(tx *bolt.Tx) error {
+		b := tx.Bucket([]byte(defaultBoltBucket)).Get([]byte(key))
+		if b == nil {
+			return ErrKeyNotFound
+		}
+		if v != nil {
+			return bs.Unmarshal(b, v)
+		}
+		return nil
+	})
+	return
+}
+
+func (bs *BoltStore) Set(key string, v interface{}) error {
+	return bs.db.Update(func(tx *bolt.Tx) (err error) {
+		var b []byte
+		if v != nil {
+			b, err = bs.Marshal(v)
+			if err != nil {
+				return
+			}
+		}
+		return tx.Bucket([]byte(defaultBoltBucket)).Put([]byte(key), b)
+	})
+}
+
+func (bs *BoltStore) ForEach(f func(string, []byte) error) error {
+	return bs.db.View(func(tx *bolt.Tx) error {
+		return tx.Bucket([]byte(defaultBoltBucket)).ForEach(func(k, v []byte) error {
+			return f(string(k), v)
+		})
+	})
+}
+
+func (bs *BoltStore) ForEachPrefix(prefix string, f func(string, []byte) error) error {
+	return bs.ForEach(func(k string, v []byte) error {
+		if trim, ok := hasTrimPrefix(k, prefix); ok {
+			return f(trim, v)
+		}
+		return nil
+	})
+}
+
+func (bs *BoltStore) Delete(key string) error {
+	return bs.db.Update(func(tx *bolt.Tx) error {
+		return tx.Bucket([]byte(defaultBoltBucket)).Delete([]byte(key))
+	})
+}
+
+func (bs *BoltStore) Close() error {
+	return bs.db.Close()
+}

pkg/store/boltstore_test.go

@@ -0,0 +1,98 @@
+// Copyright (C) 2022 Marius Schellenberger
+
+package store
+
+import (
+	"bytes"
+	"errors"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+type testData struct {
+	Data string
+}
+
+func TestBoltStore(t *testing.T) {
+	data := []testData{
+		{"123"},
+		{"hello"},
+	}
+	dir, err := os.MkdirTemp("", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(dir)
+	bs, err := NewBoltStore(filepath.Join(dir, "bolt.db"), nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = bs.Set("key0", data[0])
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = bs.Set("key1", data[1])
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t.Run("GetKey0", func(t *testing.T) {
+		var d testData
+		err := bs.Get("key0", &d)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if d != data[0] {
+			t.Error("d is not data[0]")
+		}
+	})
+	t.Run("ForEach", func(t *testing.T) {
+		err := bs.ForEach(func(k string, v []byte) error {
+			if k == "key0" || k == "key1" {
+				return nil
+			}
+			return errors.New("key0 or key1 not found")
+		})
+		if err != nil {
+			t.Fatal(err)
+		}
+	})
+	t.Run("DumpRestore", func(t *testing.T) {
+		buf := new(bytes.Buffer)
+		err := bs.Dump(buf)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if buf.Len() == 0 {
+			t.Error("no dump written")
+		}
+		err = bs.Restore(buf)
+		if err != nil {
+			t.Fatal(err)
+		}
+	})
+	t.Run("DeleteKey1", func(t *testing.T) {
+		err := bs.Delete("key1")
+		if err != nil {
+			t.Fatal(err)
+		}
+	})
+	t.Run("GetKey1", func(t *testing.T) {
+		var d testData
+		err := bs.Get("key1", &d)
+		if err == nil {
+			t.Error("key1 should be deleted")
+		}
+		if d == data[1] {
+			t.Error("d is not data[1]")
+		}
+	})
+	t.Run("Close", func(t *testing.T) {
+		err := bs.Close()
+		if err != nil {
+			t.Fatal(err)
+		}
+	})
+}

pkg/store/dump.go

@@ -0,0 +1,13 @@
+// Copyright (C) 2022 Marius Schellenberger
+
+package store
+
+import "io"
+
+type Dumper interface {
+	Dump(io.Writer) error
+}
+
+type Restorer interface {
+	Restore(io.Reader) error
+}

pkg/store/gob.go

@@ -0,0 +1,25 @@
+// Copyright (C) 2022 Marius Schellenberger
+
+package store
+
+import (
+	"bytes"
+	"encoding/gob"
+)
+
+type gobMarshaler struct{}
+
+func NewGOB() Marshaler {
+	return gobMarshaler{}
+}
+
+func (gobMarshaler) Marshal(v interface{}) (b []byte, err error) {
+	buf := new(bytes.Buffer)
+	err = gob.NewEncoder(buf).Encode(v)
+	b = buf.Bytes()
+	return
+}
+
+func (gobMarshaler) Unmarshal(data []byte, v interface{}) error {
+	return gob.NewDecoder(bytes.NewBuffer(data)).Decode(v)
+}

pkg/store/helper.go

@@ -0,0 +1,11 @@
+// Copyright (C) 2022 Marius Schellenberger
+
+package store
+
+// Parts taken from strings.TrimPrefix
+func hasTrimPrefix(s, prefix string) (string, bool) {
+	if len(s) >= len(prefix) && s[0:len(prefix)] == prefix {
+		return s[len(prefix):], true
+	}
+	return s, false
+}

pkg/store/marshal.go

@@ -0,0 +1,8 @@
+// Copyright (C) 2022 Marius Schellenberger
+
+package store
+
+type Marshaler interface {
+	Marshal(v interface{}) ([]byte, error)
+	Unmarshal(data []byte, v interface{}) error
+}

pkg/store/store.go

@@ -0,0 +1,23 @@
+// Copyright (C) 2022 Marius Schellenberger
+
+package store
+
+import "errors"
+
+var (
+	ErrKeyNotFound = errors.New("store: key not found")
+	ErrWriterIsNil = errors.New("store: writer is nil")
+	ErrReaderIsNil = errors.New("store: reader is nil")
+)
+
+type Store interface {
+	Marshaler
+	Dumper
+	Restorer
+	Get(string, interface{}) error
+	Set(string, interface{}) error
+	ForEach(func(string, []byte) error) error
+	ForEachPrefix(string, func(string, []byte) error) error
+	Delete(string) error
+	Close() error
+}