// ReadLogs read the container log and redirect into stdout and stderr.
func ReadLogs(path string, apiOpts *api.PodLogOptions, stdout, stderr io.Writer) error {
f, err := os.Open(path)
if err != nil {
return fmt.Errorf("failed to open log file %q: %v", path, err)
}
defer f.Close()
// Convert api.PodLogOptions into internal log options.
opts := newLogOptions(apiOpts, time.Now())
// Search start point based on tail line.
start, err := tail(f, opts.tail)
if err != nil {
return fmt.Errorf("failed to tail %d lines of log file %q: %v", opts.tail, path, err)
}
if _, err := f.Seek(start, os.SEEK_SET); err != nil {
return fmt.Errorf("failed to seek %d in log file %q: %v", start, path, err)
}
// Start parsing the logs.
r := bufio.NewReader(f)
// Do not create watcher here because it is not needed if `Follow` is false.
var watcher *fsnotify.Watcher
var parse parseFunc
writer := newLogWriter(stdout, stderr, opts)
msg := &logMessage{}
for {
l, err := r.ReadBytes(eol[0])
if err != nil {
if err != io.EOF { // This is an real error
return fmt.Errorf("failed to read log file %q: %v", path, err)
}
if !opts.follow {
// Return directly when reading to the end if not follow.
if len(l) > 0 {
glog.Warningf("Incomplete line in log file %q: %q", path, l)
}
glog.V(2).Infof("Finish parsing log file %q", path)
return nil
}
// Reset seek so that if this is an incomplete line,
// it will be read again.
if _, err := f.Seek(-int64(len(l)), os.SEEK_CUR); err != nil {
return fmt.Errorf("failed to reset seek in log file %q: %v", path, err)
}
if watcher == nil {
// Intialize the watcher if it has not been initialized yet.
if watcher, err = fsnotify.NewWatcher(); err != nil {
return fmt.Errorf("failed to create fsnotify watcher: %v", err)
}
defer watcher.Close()
if err := watcher.Add(f.Name()); err != nil {
return fmt.Errorf("failed to watch file %q: %v", f.Name(), err)
}
}
// Wait until the next log change.
if err := waitLogs(watcher); err != nil {
return fmt.Errorf("failed to wait logs for log file %q: %v", path, err)
}
continue
}
if parse == nil {
// Intialize the log parsing function.
parse, err = getParseFunc(l)
if err != nil {
return fmt.Errorf("failed to get parse function: %v", err)
}
}
// Parse the log line.
msg.reset()
if err := parse(l, msg); err != nil {
glog.Errorf("Failed with err %v when parsing log for log file %q: %q", err, path, l)
continue
}
// Write the log line into the stream.
if err := writer.write(msg); err != nil {
if err == errMaximumWrite {
glog.V(2).Infof("Finish parsing log file %q, hit bytes limit %d(bytes)", path, opts.bytes)
return nil
}
glog.Errorf("Failed with err %v when writing log for log file %q: %+v", err, path, msg)
}
}
}
