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moby--moby/daemon/logger/copier.go
Ankush Agarwal 41d85c014d Doc fixes in logger, update NewCopier method
Signed-off-by: Ankush Agarwal <ankushagarwal11@gmail.com>
2015-07-29 10:05:46 -07:00

71 lines
1.6 KiB
Go

package logger
import (
"bufio"
"bytes"
"io"
"sync"
"time"
"github.com/Sirupsen/logrus"
)
// Copier can copy logs from specified sources to Logger and attach
// ContainerID and Timestamp.
// Writes are concurrent, so you need implement some sync in your logger
type Copier struct {
// cid is the container id for which we are copying logs
cid string
// srcs is map of name -> reader pairs, for example "stdout", "stderr"
srcs map[string]io.Reader
dst Logger
copyJobs sync.WaitGroup
}
// NewCopier creates a new Copier
func NewCopier(cid string, srcs map[string]io.Reader, dst Logger) *Copier {
return &Copier{
cid: cid,
srcs: srcs,
dst: dst,
}
}
// Run starts logs copying
func (c *Copier) Run() {
for src, w := range c.srcs {
c.copyJobs.Add(1)
go c.copySrc(src, w)
}
}
func (c *Copier) copySrc(name string, src io.Reader) {
defer c.copyJobs.Done()
reader := bufio.NewReader(src)
for {
line, err := reader.ReadBytes('\n')
line = bytes.TrimSuffix(line, []byte{'\n'})
// ReadBytes can return full or partial output even when it failed.
// e.g. it can return a full entry and EOF.
if err == nil || len(line) > 0 {
if logErr := c.dst.Log(&Message{ContainerID: c.cid, Line: line, Source: name, Timestamp: time.Now().UTC()}); logErr != nil {
logrus.Errorf("Failed to log msg %q for logger %s: %s", line, c.dst.Name(), logErr)
}
}
if err != nil {
if err != io.EOF {
logrus.Errorf("Error scanning log stream: %s", err)
}
return
}
}
}
// Wait waits until all copying is done
func (c *Copier) Wait() {
c.copyJobs.Wait()
}