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