From a98f5b26ceed68dd71ae88c245ae653a45cfc254 Mon Sep 17 00:00:00 2001
From: Travis Jeffery <tj@travisjeffery.com>
Date: Sat, 10 Dec 2016 04:19:25 -0500
Subject: [PATCH] add log cleaner

---
 cluster/topic_partition.go  |  1 +
 commitlog/cleaner.go        | 45 +++++++++++++++++++++++++++++++++++++
 commitlog/commitlog.go      |  8 +++++++
 commitlog/commitlog_test.go | 45 ++++++++++++++++++++++++++++---------
 4 files changed, 88 insertions(+), 11 deletions(-)
 create mode 100644 commitlog/cleaner.go

diff --git a/cluster/topic_partition.go b/cluster/topic_partition.go
index 1b2ec770..8ff03907 100644
--- a/cluster/topic_partition.go
+++ b/cluster/topic_partition.go
@@ -30,6 +30,7 @@ func (partition *TopicPartition) OpenCommitLog(logDir string) error {
 	partition.CommitLog, err = commitlog.New(commitlog.Options{
 		Path:            path.Join(logDir, partition.String()),
 		MaxSegmentBytes: 1024,
+		MaxLogBytes:     -1,
 	})
 	if err != nil {
 		return err
diff --git a/commitlog/cleaner.go b/commitlog/cleaner.go
new file mode 100644
index 00000000..90203eab
--- /dev/null
+++ b/commitlog/cleaner.go
@@ -0,0 +1,45 @@
+package commitlog
+
+type Cleaner interface {
+	Clean([]*Segment) ([]*Segment, error)
+}
+
+type DeleteCleaner struct {
+	Retention struct {
+		Bytes int64
+	}
+}
+
+func NewDeleteCleaner(bytes int64) *DeleteCleaner {
+	c := &DeleteCleaner{}
+	c.Retention.Bytes = bytes
+	return c
+}
+
+func (c *DeleteCleaner) Clean(segments []*Segment) ([]*Segment, error) {
+	if len(segments) == 0 || c.Retention.Bytes == -1 {
+		return segments, nil
+	}
+	cleanedSegments := []*Segment{segments[len(segments)-1]}
+	totalBytes := cleanedSegments[0].Position
+	if len(segments) > 1 {
+		var i int
+		for i = len(segments) - 2; i > -1; i-- {
+			s := segments[i]
+			totalBytes += s.Position
+			if totalBytes > c.Retention.Bytes {
+				break
+			}
+			cleanedSegments = append([]*Segment{s}, cleanedSegments...)
+		}
+		if i > -1 {
+			for ; i != 0; i-- {
+				s := segments[i]
+				if err := s.Delete(); err != nil {
+					return nil, err
+				}
+			}
+		}
+	}
+	return cleanedSegments, nil
+}
diff --git a/commitlog/commitlog.go b/commitlog/commitlog.go
index 45eb550b..8919d245 100644
--- a/commitlog/commitlog.go
+++ b/commitlog/commitlog.go
@@ -18,6 +18,7 @@ var (
 
 type CommitLog struct {
 	Options
+	cleaner        Cleaner
 	name           string
 	mu             sync.RWMutex
 	segments       []*Segment
@@ -27,6 +28,7 @@ type CommitLog struct {
 type Options struct {
 	Path            string
 	MaxSegmentBytes int64
+	MaxLogBytes     int64
 }
 
 func New(opts Options) (*CommitLog, error) {
@@ -42,6 +44,7 @@ func New(opts Options) (*CommitLog, error) {
 	l := &CommitLog{
 		Options: opts,
 		name:    filepath.Base(path),
+		cleaner: NewDeleteCleaner(opts.MaxLogBytes),
 	}
 
 	return l, nil
@@ -176,6 +179,11 @@ func (l *CommitLog) split() error {
 	}
 	l.mu.Lock()
 	l.segments = append(l.segments, seg)
+	segments, err := l.cleaner.Clean(l.segments)
+	if err != nil {
+		return err
+	}
+	l.segments = segments
 	l.mu.Unlock()
 	l.vActiveSegment.Store(seg)
 	return nil
diff --git a/commitlog/commitlog_test.go b/commitlog/commitlog_test.go
index c0eef0a2..8fdb3fe5 100644
--- a/commitlog/commitlog_test.go
+++ b/commitlog/commitlog_test.go
@@ -61,14 +61,14 @@ func TestNewCommitLog(t *testing.T) {
 
 func TestNewCommitLogExisting(t *testing.T) {
 	var err error
-	l0 := setup(t)
+	l := setup(t)
 	defer cleanup(t)
 
 	for _, msgSet := range msgSets {
-		_, err = l0.Append(msgSet)
+		_, err = l.Append(msgSet)
 		assert.NoError(t, err)
 	}
-	assert.Equal(t, int64(2), l0.NewestOffset())
+	assert.Equal(t, int64(2), l.NewestOffset())
 
 	l1 := setup(t)
 	msgs1 := []Message{
@@ -108,28 +108,28 @@ func TestNewCommitLogExisting(t *testing.T) {
 
 func TestTruncateTo(t *testing.T) {
 	var err error
-	l0 := setup(t)
+	l := setup(t)
 	defer cleanup(t)
 
 	for _, msgSet := range msgSets {
-		_, err = l0.Append(msgSet)
+		_, err = l.Append(msgSet)
 		assert.NoError(t, err)
 	}
-	assert.Equal(t, int64(2), l0.NewestOffset())
-	assert.Equal(t, 2, len(l0.Segments()))
+	assert.Equal(t, int64(2), l.NewestOffset())
+	assert.Equal(t, 2, len(l.Segments()))
 
-	err = l0.TruncateTo(int64(1))
+	err = l.TruncateTo(int64(1))
 	assert.NoError(t, err)
-	assert.Equal(t, 1, len(l0.Segments()))
+	assert.Equal(t, 1, len(l.Segments()))
 
 	maxBytes := msgSets[0].Size()
-	_, err = l0.NewReader(ReaderOptions{
+	_, err = l.NewReader(ReaderOptions{
 		Offset:   0,
 		MaxBytes: maxBytes,
 	})
 	assert.Error(t, err)
 
-	r, err := l0.NewReader(ReaderOptions{
+	r, err := l.NewReader(ReaderOptions{
 		Offset:   1,
 		MaxBytes: maxBytes,
 	})
@@ -152,6 +152,28 @@ func TestTruncateTo(t *testing.T) {
 	}
 }
 
+func TestCleaner(t *testing.T) {
+	var err error
+	l := setup(t)
+	defer cleanup(t)
+
+	for _, msgSet := range msgSets {
+		_, err = l.Append(msgSet)
+		assert.NoError(t, err)
+	}
+	segments := l.Segments()
+	assert.Equal(t, 2, len(segments))
+
+	for _, msgSet := range msgSets {
+		_, err = l.Append(msgSet)
+		assert.NoError(t, err)
+	}
+	assert.Equal(t, 2, len(l.Segments()))
+	for i, s := range l.Segments() {
+		assert.NotEqual(t, s, segments[i])
+	}
+}
+
 func check(t *testing.T, got, want []byte) {
 	if !bytes.Equal(got, want) {
 		t.Errorf("got = %s, want %s", string(got), string(want))
@@ -162,6 +184,7 @@ func setup(t *testing.T) *CommitLog {
 	opts := Options{
 		Path:            path,
 		MaxSegmentBytes: 6,
+		MaxLogBytes:     30,
 	}
 	l, err := New(opts)
 	assert.NoError(t, err)