Skip to content
Branch: master
Find file Copy path
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
148 lines (126 sloc) 4.47 KB
// RAINBOND, Application Management Platform
// Copyright (C) 2014-2017 Goodrain Co., Ltd.
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version. For any non-GPL usage of Rainbond,
// one or multiple Commercial Licenses authorized by Goodrain Co., Ltd.
// must be obtained first.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <>.
package logger
import (
// ErrReadLogsNotSupported is returned when the logger does not support reading logs.
var ErrReadLogsNotSupported = errors.New("configured logging driver does not support reading")
const (
logWatcherBufferSize = 4096
var messagePool = &sync.Pool{New: func() interface{} { return &Message{Line: make([]byte, 0, 256)} }}
// NewMessage returns a new message from the message sync.Pool
func NewMessage() *Message {
return messagePool.Get().(*Message)
// PutMessage puts the specified message back n the message pool.
// The message fields are reset before putting into the pool.
func PutMessage(msg *Message) {
// Message is datastructure that represents piece of output produced by some
// container. The Line member is a slice of an array whose contents can be
// changed after a log driver's Log() method returns.
// Any changes made to this struct must also be updated in the `reset` function
type Message struct {
Line []byte
Source string
Timestamp time.Time
Attrs LogAttributes
Partial bool
// reset sets the message back to default values
// This is used when putting a message back into the message pool.
// Any changes to the `Message` struct should be reflected here.
func (m *Message) reset() {
m.Line = m.Line[:0]
m.Source = ""
m.Attrs = nil
m.Partial = false
// LogAttributes is used to hold the extra attributes available in the log message
// Primarily used for converting the map type to string and sorting.
type LogAttributes map[string]string
// LogWatcher is used when consuming logs read from the LogReader interface.
type LogWatcher struct {
// For sending log messages to a reader.
Msg chan *Message
// For sending error messages that occur while while reading logs.
Err chan error
closeOnce sync.Once
closeNotifier chan struct{}
consumerGone chan struct{}
consumerOnce sync.Once
producerOnce sync.Once
producerGone chan struct{}
// NewLogWatcher returns a new LogWatcher.
func NewLogWatcher() *LogWatcher {
return &LogWatcher{
Msg: make(chan *Message, logWatcherBufferSize),
Err: make(chan error, 1),
closeNotifier: make(chan struct{}),
producerGone: make(chan struct{}),
consumerGone: make(chan struct{}),
// Close notifies the underlying log reader to stop.
func (w *LogWatcher) Close() {
// only close if not already closed
w.closeOnce.Do(func() {
// WatchConsumerGone returns a channel receiver that receives notification
// when the log watcher consumer is gone.
func (w *LogWatcher) WatchConsumerGone() <-chan struct{} {
return w.consumerGone
// ConsumerGone notifies that the logs consumer is gone.
func (w *LogWatcher) ConsumerGone() {
// only close if not already closed
w.consumerOnce.Do(func() {
// WatchClose returns a channel receiver that receives notification
// when the watcher has been closed. This should only be called from
// one goroutine.
func (w *LogWatcher) WatchClose() <-chan struct{} {
return w.closeNotifier
// ProducerGone notifies the underlying log reader that
// the logs producer (a container) is gone.
func (w *LogWatcher) ProducerGone() {
// only close if not already closed
w.producerOnce.Do(func() {
// WatchProducerGone returns a channel receiver that receives notification
// once the logs producer (a container) is gone.
func (w *LogWatcher) WatchProducerGone() <-chan struct{} {
return w.producerGone
// Logger is the interface for docker logging drivers.
type Logger interface {
Log(*Message) error
Name() string
Close() error
You can’t perform that action at this time.