Function logCriuErrors

libcontainer/criu_linux.go:821–867

logCriuErrors tries to find and log errors from a criu log file. The output is similar to what "grep -n -B5 Error" does.

(dir, file string)

// logCriuErrors tries to find and log errors from a criu log file.
// The output is similar to what "grep -n -B5 Error" does.
func logCriuErrors(dir, file string) {
	lookFor := []byte("Error") // Print the line that contains this...
	const max = 5 + 1          // ... and a few preceding lines.

	logFile := filepath.Join(dir, file)
	f, err := os.Open(logFile)
	if err != nil {
		logrus.Warn(err)
		return
	}
	defer f.Close()

	var lines [max][]byte
	var idx, lineNo, printedLineNo int
	s := bufio.NewScanner(f)
	for s.Scan() {
		lineNo++
		lines[idx] = s.Bytes()
		idx = (idx + 1) % max
		if !bytes.Contains(s.Bytes(), lookFor) {
			continue
		}
		// Found an error.
		if printedLineNo == 0 {
			logrus.Warnf("--- Quoting %q", logFile)
		} else if lineNo-max > printedLineNo {
			// Mark the gap.
			logrus.Warn("...")
		}
		// Print the last lines.
		for add := range max {
			i := (idx + add) % max
			s := lines[i]
			actLineNo := lineNo + add - max + 1
			if len(s) > 0 && actLineNo > printedLineNo {
				logrus.Warnf("%d:%s", actLineNo, s)
				printedLineNo = actLineNo
			}
		}
	}
	if printedLineNo != 0 {
		logrus.Warn("---") // End of "Quoting ...".
	}
	if err := s.Err(); err != nil {
		logrus.Warnf("read %q: %v", logFile, err)
	}
}

func (c *Container) criuApplyCgroups(pid int, req *criurpc.CriuReq) error {
	// need to apply cgroups only on restore