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package log_buffer
import ( "bytes" "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 *bytes.Buffer }
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 lastTsNs int64 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(partitionKey, 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() tsNs := ts.UnixNano() if m.lastTsNs >= tsNs { // this is unlikely to happen, but just in case
tsNs = m.lastTsNs + 1 ts = time.Unix(0, tsNs) } m.lastTsNs = tsNs logEntry := &filer_pb.LogEntry{ TsNs: tsNs, PartitionKeyHash: util.HashToInt32(partitionKey), 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
// fmt.Printf("entry size %d total %d count %d, buffer:%p\n", size, m.pos, len(m.idx), m)
}
func (m *LogBuffer) Shutdown() { m.Lock() defer m.Unlock()
if m.isStopping { return } m.isStopping = true toFlush := m.copyToFlush() m.flushChan <- toFlush close(m.flushChan) }
func (m *LogBuffer) loopFlush() { for d := range m.flushChan { if d != nil { // fmt.Printf("flush [%v, %v] size %d\n", d.startTime, d.stopTime, len(d.data.Bytes()))
m.flushFn(d.startTime, d.stopTime, d.data.Bytes()) d.releaseMemory() } } }
func (m *LogBuffer) loopInterval() { for !m.isStopping { time.Sleep(m.flushInterval) m.Lock() if m.isStopping { m.Unlock() return } // println("loop interval")
toFlush := m.copyToFlush() m.flushChan <- toFlush m.Unlock() } }
func (m *LogBuffer) copyToFlush() *dataToFlush {
if m.pos > 0 { // fmt.Printf("flush buffer %d pos %d empty space %d\n", len(m.buf), m.pos, len(m.buf)-m.pos)
var d *dataToFlush if m.flushFn != nil { d = &dataToFlush{ startTime: m.startTime, stopTime: m.stopTime, data: copiedBytes(m.buf[:m.pos]), } } // fmt.Printf("flusing [0,%d) with %d entries\n", m.pos, len(m.idx))
m.buf = m.prevBuffers.SealBuffer(m.startTime, m.stopTime, m.buf, m.pos) m.pos = 0 m.idx = m.idx[:0] return d } return nil }
func (d *dataToFlush) releaseMemory() { d.data.Reset() bufferPool.Put(d.data) }
func (m *LogBuffer) ReadFromBuffer(lastReadTime time.Time) (bufferCopy *bytes.Buffer) { m.RLock() defer m.RUnlock()
/* fmt.Printf("read buffer %p: %v last stop time: [%v,%v], pos %d, entries:%d, prevBufs:%d\n", m, lastReadTime, m.startTime, m.stopTime, m.pos, len(m.idx), len(m.prevBuffers.buffers)) for i, prevBuf := range m.prevBuffers.buffers { fmt.Printf(" prev %d : %s\n", i, prevBuf.String()) } */
if lastReadTime.Equal(m.stopTime) { return nil } if lastReadTime.After(m.stopTime) { // glog.Fatalf("unexpected last read time %v, older than latest %v", lastReadTime, m.stopTime)
return nil } if lastReadTime.Before(m.startTime) { // println("checking ", lastReadTime.UnixNano())
for i, buf := range m.prevBuffers.buffers { if buf.startTime.After(lastReadTime) { if i == 0 { // println("return the earliest in memory", buf.startTime.UnixNano())
return copiedBytes(buf.buf[:buf.size]) } // println("return the", i, "th in memory", buf.startTime.UnixNano())
return copiedBytes(buf.buf[:buf.size]) } if !buf.startTime.After(lastReadTime) && buf.stopTime.After(lastReadTime) { pos := buf.locateByTs(lastReadTime) // fmt.Printf("locate buffer[%d] pos %d\n", i, pos)
return copiedBytes(buf.buf[pos:buf.size]) } } // println("return the current buf", lastReadTime.UnixNano())
return 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.SubscribeMetadataResponse{} 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, pos) 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 { // fmt.Printf("found l=%d, m-1=%d(ts=%d), m=%d(ts=%d), h=%d [%d, %d) \n", l, mid-1, prevT, mid, t, h, pos, m.pos)
return copiedBytes(m.buf[pos:m.pos]) } h = mid } // fmt.Printf("l=%d, h=%d\n", l, h)
}
// FIXME: this could be that the buffer has been flushed already
return nil
} func (m *LogBuffer) ReleaseMemory(b *bytes.Buffer) { bufferPool.Put(b) }
var bufferPool = sync.Pool{ New: func() interface{} { return new(bytes.Buffer) }, }
func copiedBytes(buf []byte) (copied *bytes.Buffer) { copied = bufferPool.Get().(*bytes.Buffer) copied.Reset() copied.Write(buf) return }
func readTs(buf []byte, pos int) (size int, ts int64) {
size = int(util.BytesToUint32(buf[pos : pos+4])) entryData := buf[pos+4 : pos+4+size] logEntry := &filer_pb.LogEntry{}
err := proto.Unmarshal(entryData, logEntry) if err != nil { glog.Fatalf("unexpected unmarshal filer_pb.LogEntry: %v", err) } return size, logEntry.TsNs
}
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