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moby--moby/pkg/broadcastwriter/broadcastwriter.go
unclejack 153f98bad5 pkg/broadcastwriter: reset after 4 KB w/o stream
Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com>
2015-04-01 01:26:19 +03:00

122 lines
2.7 KiB
Go

package broadcastwriter
import (
"bytes"
"io"
"sync"
"time"
"github.com/Sirupsen/logrus"
"github.com/docker/docker/pkg/jsonlog"
"github.com/docker/docker/pkg/timeutils"
)
// BroadcastWriter accumulate multiple io.WriteCloser by stream.
type BroadcastWriter struct {
sync.Mutex
buf *bytes.Buffer
jsLogBuf *bytes.Buffer
streams map[string](map[io.WriteCloser]struct{})
}
// AddWriter adds new io.WriteCloser for stream.
// If stream is "", then all writes proceed as is. Otherwise every line from
// input will be packed to serialized jsonlog.JSONLog.
func (w *BroadcastWriter) AddWriter(writer io.WriteCloser, stream string) {
w.Lock()
if _, ok := w.streams[stream]; !ok {
w.streams[stream] = make(map[io.WriteCloser]struct{})
}
w.streams[stream][writer] = struct{}{}
w.Unlock()
}
// Write writes bytes to all writers. Failed writers will be evicted during
// this call.
func (w *BroadcastWriter) Write(p []byte) (n int, err error) {
w.Lock()
if writers, ok := w.streams[""]; ok {
for sw := range writers {
if n, err := sw.Write(p); err != nil || n != len(p) {
// On error, evict the writer
delete(writers, sw)
}
}
if len(w.streams) == 1 {
if w.buf.Len() >= 4096 {
w.buf.Reset()
} else {
w.buf.Write(p)
}
w.Unlock()
return len(p), nil
}
}
if w.jsLogBuf == nil {
w.jsLogBuf = new(bytes.Buffer)
w.jsLogBuf.Grow(1024)
}
var timestamp string
created := time.Now().UTC()
w.buf.Write(p)
for {
if n := w.buf.Len(); n == 0 {
break
}
i := bytes.IndexByte(w.buf.Bytes(), '\n')
if i < 0 {
break
}
lineBytes := w.buf.Next(i + 1)
if timestamp == "" {
timestamp, err = timeutils.FastMarshalJSON(created)
if err != nil {
continue
}
}
for stream, writers := range w.streams {
if stream == "" {
continue
}
jsonLog := jsonlog.JSONLogBytes{Log: lineBytes, Stream: stream, Created: timestamp}
err = jsonLog.MarshalJSONBuf(w.jsLogBuf)
if err != nil {
logrus.Errorf("Error making JSON log line: %s", err)
continue
}
w.jsLogBuf.WriteByte('\n')
b := w.jsLogBuf.Bytes()
for sw := range writers {
if _, err := sw.Write(b); err != nil {
delete(writers, sw)
}
}
}
w.jsLogBuf.Reset()
}
w.jsLogBuf.Reset()
w.Unlock()
return len(p), nil
}
// Clean closes and removes all writers. Last non-eol-terminated part of data
// will be saved.
func (w *BroadcastWriter) Clean() error {
w.Lock()
for _, writers := range w.streams {
for w := range writers {
w.Close()
}
}
w.streams = make(map[string](map[io.WriteCloser]struct{}))
w.Unlock()
return nil
}
func New() *BroadcastWriter {
return &BroadcastWriter{
streams: make(map[string](map[io.WriteCloser]struct{})),
buf: bytes.NewBuffer(nil),
}
}