refactoring

weed/util/log_buffer/log_buffer.go

@@ -0,0 +1,220 @@
+package log_buffer
+
+import (
+	"sync"
+	"time"
+
+	"github.com/golang/protobuf/proto"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+	"github.com/chrislusf/seaweedfs/weed/util"
+)
+
+const BufferSize = 4 * 1024 * 1024
+const PreviousBufferCount = 3
+
+type dataToFlush struct {
+	startTime time.Time
+	stopTime  time.Time
+	data      []byte
+}
+
+type LogBuffer struct {
+	prevBuffers   *SealedBuffers
+	buf           []byte
+	idx           []int
+	pos           int
+	startTime     time.Time
+	stopTime      time.Time
+	sizeBuf       []byte
+	flushInterval time.Duration
+	flushFn       func(startTime, stopTime time.Time, buf []byte)
+	notifyFn      func()
+	isStopping    bool
+	flushChan     chan *dataToFlush
+	sync.RWMutex
+}
+
+func NewLogBuffer(flushInterval time.Duration, flushFn func(startTime, stopTime time.Time, buf []byte), notifyFn func()) *LogBuffer {
+	lb := &LogBuffer{
+		prevBuffers:   newSealedBuffers(PreviousBufferCount),
+		buf:           make([]byte, BufferSize),
+		sizeBuf:       make([]byte, 4),
+		flushInterval: flushInterval,
+		flushFn:       flushFn,
+		notifyFn:      notifyFn,
+		flushChan:     make(chan *dataToFlush, 256),
+	}
+	go lb.loopFlush()
+	go lb.loopInterval()
+	return lb
+}
+
+func (m *LogBuffer) AddToBuffer(key, data []byte) {
+
+	m.Lock()
+	defer func() {
+		m.Unlock()
+		if m.notifyFn != nil {
+			m.notifyFn()
+		}
+	}()
+
+	// need to put the timestamp inside the lock
+	ts := time.Now()
+	logEntry := &filer_pb.LogEntry{
+		TsNs:             ts.UnixNano(),
+		PartitionKeyHash: util.HashToInt32(key),
+		Data:             data,
+	}
+
+	logEntryData, _ := proto.Marshal(logEntry)
+
+	size := len(logEntryData)
+
+	if m.pos == 0 {
+		m.startTime = ts
+	}
+
+	if m.startTime.Add(m.flushInterval).Before(ts) || len(m.buf)-m.pos < size+4 {
+		m.flushChan <- m.copyToFlush()
+		m.startTime = ts
+		if len(m.buf) < size+4 {
+			m.buf = make([]byte, 2*size+4)
+		}
+	}
+	m.stopTime = ts
+
+	m.idx = append(m.idx, m.pos)
+	util.Uint32toBytes(m.sizeBuf, uint32(size))
+	copy(m.buf[m.pos:m.pos+4], m.sizeBuf)
+	copy(m.buf[m.pos+4:m.pos+4+size], logEntryData)
+	m.pos += size + 4
+}
+
+func (m *LogBuffer) Shutdown() {
+	if m.isStopping {
+		return
+	}
+	m.isStopping = true
+	m.Lock()
+	toFlush := m.copyToFlush()
+	m.Unlock()
+	m.flushChan <- toFlush
+	close(m.flushChan)
+}
+
+func (m *LogBuffer) loopFlush() {
+	for d := range m.flushChan {
+		if d != nil {
+			m.flushFn(d.startTime, d.stopTime, d.data)
+		}
+	}
+}
+
+func (m *LogBuffer) loopInterval() {
+	for !m.isStopping {
+		m.Lock()
+		toFlush := m.copyToFlush()
+		m.Unlock()
+		m.flushChan <- toFlush
+		time.Sleep(m.flushInterval)
+	}
+}
+
+func (m *LogBuffer) copyToFlush() *dataToFlush {
+
+	if m.flushFn != nil && m.pos > 0 {
+		// fmt.Printf("flush buffer %d pos %d empty space %d\n", len(m.buf), m.pos, len(m.buf)-m.pos)
+		d := &dataToFlush{
+			startTime: m.startTime,
+			stopTime:  m.stopTime,
+			data:      copiedBytes(m.buf[:m.pos]),
+		}
+		m.buf = m.prevBuffers.SealBuffer(m.startTime, m.stopTime, m.buf)
+		m.pos = 0
+		m.idx = m.idx[:0]
+		return d
+	}
+	return nil
+}
+
+func (m *LogBuffer) ReadFromBuffer(lastReadTime time.Time) (ts time.Time, bufferCopy []byte) {
+	m.RLock()
+	defer m.RUnlock()
+
+	// fmt.Printf("read from buffer: %v\n", lastReadTime)
+
+	if lastReadTime.Equal(m.stopTime) {
+		return lastReadTime, nil
+	}
+	if lastReadTime.After(m.stopTime) {
+		// glog.Fatalf("unexpected last read time %v, older than latest %v", lastReadTime, m.stopTime)
+		return lastReadTime, nil
+	}
+	if lastReadTime.Before(m.startTime) {
+		return m.stopTime, copiedBytes(m.buf[:m.pos])
+	}
+
+	lastTs := lastReadTime.UnixNano()
+	l, h := 0, len(m.idx)-1
+
+	/*
+		for i, pos := range m.idx {
+			logEntry, ts := readTs(m.buf, pos)
+			event := &filer_pb.FullEventNotification{}
+			proto.Unmarshal(logEntry.Data, event)
+			entry := event.EventNotification.OldEntry
+			if entry == nil {
+				entry = event.EventNotification.NewEntry
+			}
+			fmt.Printf("entry %d ts: %v offset:%d dir:%s name:%s\n", i, time.Unix(0, ts), pos, event.Directory, entry.Name)
+		}
+		fmt.Printf("l=%d, h=%d\n", l, h)
+	*/
+
+	for l <= h {
+		mid := (l + h) / 2
+		pos := m.idx[mid]
+		_, t := readTs(m.buf, m.idx[mid])
+		if t <= lastTs {
+			l = mid + 1
+		} else if lastTs < t {
+			var prevT int64
+			if mid > 0 {
+				_, prevT = readTs(m.buf, m.idx[mid-1])
+			}
+			if prevT <= lastTs {
+				// println("found mid = ", mid)
+				return time.Unix(0, t), copiedBytes(m.buf[pos:m.pos])
+			}
+			h = mid - 1
+		}
+		// fmt.Printf("l=%d, h=%d\n", l, h)
+	}
+
+	// FIXME: this could be that the buffer has been flushed already
+	// println("not found")
+	return lastReadTime, nil
+
+}
+func copiedBytes(buf []byte) (copied []byte) {
+	copied = make([]byte, len(buf))
+	copy(copied, buf)
+	return
+}
+
+func readTs(buf []byte, pos int) (*filer_pb.LogEntry, int64) {
+
+	size := util.BytesToUint32(buf[pos : pos+4])
+	entryData := buf[pos+4 : pos+4+int(size)]
+	logEntry := &filer_pb.LogEntry{}
+
+	err := proto.Unmarshal(entryData, logEntry)
+	if err != nil {
+		glog.Fatalf("unexpected unmarshal filer_pb.LogEntry: %v", err)
+	}
+	return logEntry, logEntry.TsNs
+
+}

weed/util/log_buffer/sealed_buffer.go

@@ -0,0 +1,40 @@
+package log_buffer
+
+import "time"
+
+type MemBuffer struct {
+	buf       []byte
+	startTime time.Time
+	stopTime  time.Time
+}
+
+type SealedBuffers struct {
+	buffers []*MemBuffer
+}
+
+func newSealedBuffers(size int) *SealedBuffers {
+	sbs := &SealedBuffers{}
+
+	sbs.buffers = make([]*MemBuffer, size)
+	for i := 0; i < size; i++ {
+		sbs.buffers[i] = &MemBuffer{
+			buf: make([]byte, BufferSize),
+		}
+	}
+
+	return sbs
+}
+
+func (sbs *SealedBuffers) SealBuffer(startTime, stopTime time.Time, buf []byte) (newBuf []byte) {
+	oldMemBuffer := sbs.buffers[0]
+	size := len(sbs.buffers)
+	for i := 0; i < size-1; i++ {
+		sbs.buffers[i].buf = sbs.buffers[i+1].buf
+		sbs.buffers[i].startTime = sbs.buffers[i+1].startTime
+		sbs.buffers[i].stopTime = sbs.buffers[i+1].stopTime
+	}
+	sbs.buffers[size-1].buf = buf
+	sbs.buffers[size-1].startTime = startTime
+	sbs.buffers[size-1].stopTime = stopTime
+	return oldMemBuffer.buf
+}