Support Option Initialization Pattern (#37)

benchmark/bench_test.go

@@ -14,13 +14,12 @@ var walFile *wal.WAL
 
 func init() {
 	dir, _ := os.MkdirTemp("", "wal-benchmark-test")
-	opts := wal.Options{
-		DirPath:        dir,
-		SegmentFileExt: ".SEG",
-		SegmentSize:    wal.GB,
-	}
 	var err error
-	walFile, err = wal.Open(opts)
+	walFile, err = wal.Open(
+		wal.WithDirPath(dir),
+		wal.WithSegmentFileExt(".SEG"),
+		wal.WithSegmentSize(wal.GB),
+	)
 	if err != nil {
 		panic(err)
 	}

examples/main.go

@@ -9,7 +9,7 @@ import (
 )
 
 func main() {
-	walFile, _ := wal.Open(wal.DefaultOptions)
+	walFile, _ := wal.Open()
 	// write some data
 	chunkPosition, _ := walFile.Write([]byte("some data 1"))
 	// read by the position

options.go

@@ -2,6 +2,8 @@ package wal
 
 import "os"
 
+type Option func(*Options)
+
 // Options represents the configuration options for a Write-Ahead Log (WAL).
 type Options struct {
 	// DirPath specifies the directory path where the WAL segment files will be stored.
@@ -45,3 +47,38 @@ var DefaultOptions = Options{
 	Sync:           false,
 	BytesPerSync:   0,
 }
+
+// WithDirPath sets the directory path where the WAL segment files will be stored.
+func WithDirPath(dir string) Option {
+	return func(o *Options) {
+		o.DirPath = dir
+	}
+}
+
+// WithSegmentSize sets the maximum size of each segment file in bytes.
+func WithSegmentSize(size int64) Option {
+	return func(o *Options) {
+		o.SegmentSize = size
+	}
+}
+
+// WithSegmentFileExt sets the file extension of the segment files.
+func WithSegmentFileExt(ext string) Option {
+	return func(o *Options) {
+		o.SegmentFileExt = ext
+	}
+}
+
+// WithSync sets the whether to synchronize writes through os buffer cache and down onto the actual disk.
+func WithSync(sync bool) Option {
+	return func(o *Options) {
+		o.Sync = sync
+	}
+}
+
+// WithBytesPerSync sets the number of bytes to write before calling fsync.
+func WithBytesPerSync(bytesPerSync uint32) Option {
+	return func(o *Options) {
+		o.BytesPerSync = bytesPerSync
+	}
+}

wal.go

@@ -33,7 +33,7 @@ var (
 type WAL struct {
 	activeSegment     *segment               // active segment file, used for new incoming writes.
 	olderSegments     map[SegmentID]*segment // older segment files, only used for read.
-	options           Options
+	options           *Options
 	mu                sync.RWMutex
 	bytesWrite        uint32
 	renameIds         []SegmentID
@@ -56,7 +56,12 @@ type Reader struct {
 // Open opens a WAL with the given options.
 // It will create the directory if not exists, and open all segment files in the directory.
 // If there is no segment file in the directory, it will create a new one.
-func Open(options Options) (*WAL, error) {
+func Open(opts ...Option) (*WAL, error) {
+	options := &DefaultOptions
+	for _, opt := range opts {
+		opt(options)
+	}
+
 	if !strings.HasPrefix(options.SegmentFileExt, ".") {
 		return nil, fmt.Errorf("segment file extension must start with '.'")
 	}

wal_test.go

@@ -1,11 +1,12 @@
 package wal
 
 import (
-	"github.com/stretchr/testify/assert"
 	"io"
 	"os"
 	"strings"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func destroyWAL(wal *WAL) {
@@ -17,12 +18,11 @@ func destroyWAL(wal *WAL) {
 
 func TestWAL_WriteALL(t *testing.T) {
 	dir, _ := os.MkdirTemp("", "wal-test-write-batch-1")
-	opts := Options{
-		DirPath:        dir,
-		SegmentFileExt: ".SEG",
-		SegmentSize:    32 * 1024 * 1024,
-	}
-	wal, err := Open(opts)
+	wal, err := Open(
+		WithDirPath(dir),
+		WithSegmentFileExt(".SEG"),
+		WithSegmentSize(32*1024*1024),
+	)
 	assert.Nil(t, err)
 	defer destroyWAL(wal)
 
@@ -35,12 +35,11 @@ func TestWAL_WriteALL(t *testing.T) {
 
 func TestWAL_Write(t *testing.T) {
 	dir, _ := os.MkdirTemp("", "wal-test-write1")
-	opts := Options{
-		DirPath:        dir,
-		SegmentFileExt: ".SEG",
-		SegmentSize:    32 * 1024 * 1024,
-	}
-	wal, err := Open(opts)
+	wal, err := Open(
+		WithDirPath(dir),
+		WithSegmentFileExt(".SEG"),
+		WithSegmentSize(32*1024*1024),
+	)
 	assert.Nil(t, err)
 	defer destroyWAL(wal)
 
@@ -68,12 +67,11 @@ func TestWAL_Write(t *testing.T) {
 
 func TestWAL_Write_large(t *testing.T) {
 	dir, _ := os.MkdirTemp("", "wal-test-write2")
-	opts := Options{
-		DirPath:        dir,
-		SegmentFileExt: ".SEG",
-		SegmentSize:    32 * 1024 * 1024,
-	}
-	wal, err := Open(opts)
+	wal, err := Open(
+		WithDirPath(dir),
+		WithSegmentFileExt(".SEG"),
+		WithSegmentSize(32*1024*1024),
+	)
 	assert.Nil(t, err)
 	defer destroyWAL(wal)
 
@@ -82,12 +80,11 @@ func TestWAL_Write_large(t *testing.T) {
 
 func TestWAL_Write_large2(t *testing.T) {
 	dir, _ := os.MkdirTemp("", "wal-test-write3")
-	opts := Options{
-		DirPath:        dir,
-		SegmentFileExt: ".SEG",
-		SegmentSize:    32 * 1024 * 1024,
-	}
-	wal, err := Open(opts)
+	wal, err := Open(
+		WithDirPath(dir),
+		WithSegmentFileExt(".SEG"),
+		WithSegmentSize(32*1024*1024),
+	)
 	assert.Nil(t, err)
 	defer destroyWAL(wal)
 
@@ -96,12 +93,11 @@ func TestWAL_Write_large2(t *testing.T) {
 
 func TestWAL_OpenNewActiveSegment(t *testing.T) {
 	dir, _ := os.MkdirTemp("", "wal-test-new-active-segment")
-	opts := Options{
-		DirPath:        dir,
-		SegmentFileExt: ".SEG",
-		SegmentSize:    32 * 1024 * 1024,
-	}
-	wal, err := Open(opts)
+	wal, err := Open(
+		WithDirPath(dir),
+		WithSegmentFileExt(".SEG"),
+		WithSegmentSize(32*1024*1024),
+	)
 	assert.Nil(t, err)
 	defer destroyWAL(wal)
 
@@ -119,12 +115,11 @@ func TestWAL_OpenNewActiveSegment(t *testing.T) {
 
 func TestWAL_IsEmpty(t *testing.T) {
 	dir, _ := os.MkdirTemp("", "wal-test-is-empty")
-	opts := Options{
-		DirPath:        dir,
-		SegmentFileExt: ".SEG",
-		SegmentSize:    32 * 1024 * 1024,
-	}
-	wal, err := Open(opts)
+	wal, err := Open(
+		WithDirPath(dir),
+		WithSegmentFileExt(".SEG"),
+		WithSegmentSize(32*1024*1024),
+	)
 	assert.Nil(t, err)
 	defer destroyWAL(wal)
 
@@ -135,12 +130,11 @@ func TestWAL_IsEmpty(t *testing.T) {
 
 func TestWAL_Reader(t *testing.T) {
 	dir, _ := os.MkdirTemp("", "wal-test-wal-reader")
-	opts := Options{
-		DirPath:        dir,
-		SegmentFileExt: ".SEG",
-		SegmentSize:    32 * 1024 * 1024,
-	}
-	wal, err := Open(opts)
+	wal, err := Open(
+		WithDirPath(dir),
+		WithSegmentFileExt(".SEG"),
+		WithSegmentSize(32*1024*1024),
+	)
 	assert.Nil(t, err)
 	defer destroyWAL(wal)
 
@@ -174,7 +168,11 @@ func TestWAL_Reader(t *testing.T) {
 	err = wal.Close()
 	assert.Nil(t, err)
 
-	wal2, err := Open(opts)
+	wal2, err := Open(
+		WithDirPath(dir),
+		WithSegmentFileExt(".SEG"),
+		WithSegmentSize(32*1024*1024),
+	)
 	assert.Nil(t, err)
 	defer func() {
 		_ = wal2.Close()
@@ -239,12 +237,11 @@ func testWriteAndIterate(t *testing.T, wal *WAL, size int, valueSize int) {
 
 func TestWAL_Delete(t *testing.T) {
 	dir, _ := os.MkdirTemp("", "wal-test-delete")
-	opts := Options{
-		DirPath:        dir,
-		SegmentFileExt: ".SEG",
-		SegmentSize:    32 * 1024 * 1024,
-	}
-	wal, err := Open(opts)
+	wal, err := Open(
+		WithDirPath(dir),
+		WithSegmentFileExt(".SEG"),
+		WithSegmentSize(32*1024*1024),
+	)
 	assert.Nil(t, err)
 	testWriteAndIterate(t, wal, 2000, 512)
 	assert.False(t, wal.IsEmpty())
@@ -253,19 +250,22 @@ func TestWAL_Delete(t *testing.T) {
 	err = wal.Delete()
 	assert.Nil(t, err)
 
-	wal, err = Open(opts)
+	wal, err = Open(
+		WithDirPath(dir),
+		WithSegmentFileExt(".SEG"),
+		WithSegmentSize(32*1024*1024),
+	)
 	assert.Nil(t, err)
 	assert.True(t, wal.IsEmpty())
 }
 
 func TestWAL_ReaderWithStart(t *testing.T) {
 	dir, _ := os.MkdirTemp("", "wal-test-wal-reader-with-start")
-	opts := Options{
-		DirPath:        dir,
-		SegmentFileExt: ".SEG",
-		SegmentSize:    8 * 1024 * 1024,
-	}
-	wal, err := Open(opts)
+	wal, err := Open(
+		WithDirPath(dir),
+		WithSegmentFileExt(".SEG"),
+		WithSegmentSize(8*1024*1024),
+	)
 	assert.Nil(t, err)
 	defer destroyWAL(wal)
 
@@ -295,12 +295,11 @@ func TestWAL_ReaderWithStart(t *testing.T) {
 
 func TestWAL_RenameFileExt(t *testing.T) {
 	dir, _ := os.MkdirTemp("", "wal-test-rename-ext")
-	opts := Options{
-		DirPath:        dir,
-		SegmentFileExt: ".VLOG.1.temp",
-		SegmentSize:    8 * 1024 * 1024,
-	}
-	wal, err := Open(opts)
+	wal, err := Open(
+		WithDirPath(dir),
+		WithSegmentFileExt(".VLOG.1.temp"),
+		WithSegmentSize(8*1024*1024),
+	)
 	assert.Nil(t, err)
 	defer destroyWAL(wal)
 	testWriteAndIterate(t, wal, 20000, 512)
@@ -311,8 +310,7 @@ func TestWAL_RenameFileExt(t *testing.T) {
 	err = wal.RenameFileExt(".VLOG.1")
 	assert.Nil(t, err)
 
-	opts.SegmentFileExt = ".VLOG.1"
-	wal2, err := Open(opts)
+	wal2, err := Open(WithSegmentFileExt(".VLOG.1"))
 	assert.Nil(t, err)
 	defer func() {
 		_ = wal2.Close()