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package logs
import (
"fmt"
"io"
"os"
"strings"
"sync"
"time"
"github.com/containers/podman/v2/libpod/logs/reversereader"
"github.com/hpcloud/tail"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
)
const (
// LogTimeFormat is the time format used in the log.
// It is a modified version of RFC3339Nano that guarantees trailing
// zeroes are not trimmed, taken from
// https://github.com/golang/go/issues/19635
LogTimeFormat = "2006-01-02T15:04:05.000000000Z07:00"
// PartialLogType signifies a log line that exceeded the buffer
// length and needed to spill into a new line
PartialLogType = "P"
// FullLogType signifies a log line is full
FullLogType = "F"
)
// LogOptions is the options you can use for logs
type LogOptions struct {
Details bool
Follow bool
Since time.Time
Tail int64
Timestamps bool
Multi bool
WaitGroup *sync.WaitGroup
UseName bool
}
// LogLine describes the information for each line of a log
type LogLine struct {
Device string
ParseLogType string
Time time.Time
Msg string
CID string
CName string
}
// GetLogFile returns an hp tail for a container given options
func GetLogFile(path string, options *LogOptions) (*tail.Tail, []*LogLine, error) {
var (
whence int
err error
logTail []*LogLine
)
// whence 0=origin, 2=end
if options.Tail >= 0 {
whence = 2
}
if options.Tail > 0 {
logTail, err = getTailLog(path, int(options.Tail))
if err != nil {
return nil, nil, err
}
}
seek := tail.SeekInfo{
Offset: 0,
Whence: whence,
}
t, err := tail.TailFile(path, tail.Config{MustExist: true, Poll: true, Follow: options.Follow, Location: &seek, Logger: tail.DiscardingLogger, ReOpen: options.Follow})
return t, logTail, err
}
func getTailLog(path string, tail int) ([]*LogLine, error) {
var (
nlls []*LogLine
nllCounter int
leftover string
partial string
tailLog []*LogLine
)
f, err := os.Open(path)
if err != nil {
return nil, err
}
rr, err := reversereader.NewReverseReader(f)
if err != nil {
return nil, err
}
inputs := make(chan []string)
go func() {
for {
s, err := rr.Read()
if err != nil {
if errors.Cause(err) == io.EOF {
inputs <- []string{leftover}
} else {
logrus.Error(err)
}
close(inputs)
if err := f.Close(); err != nil {
logrus.Error(err)
}
break
}
line := strings.Split(s+leftover, "\n")
if len(line) > 1 {
inputs <- line[1:]
}
leftover = line[0]
}
}()
for i := range inputs {
// the incoming array is FIFO; we want FIFO so
// reverse the slice read order
for j := len(i) - 1; j >= 0; j-- {
// lines that are "" are junk
if len(i[j]) < 1 {
continue
}
// read the content in reverse and add each nll until we have the same
// number of F type messages as the desired tail
nll, err := NewLogLine(i[j])
if err != nil {
return nil, err
}
nlls = append(nlls, nll)
if !nll.Partial() {
nllCounter++
}
}
// if we have enough log lines, we can hangup
if nllCounter >= tail {
break
}
}
// re-assemble the log lines and trim (if needed) to the
// tail length
for _, nll := range nlls {
if nll.Partial() {
partial += nll.Msg
} else {
nll.Msg += partial
// prepend because we need to reverse the order again to FIFO
tailLog = append([]*LogLine{nll}, tailLog...)
partial = ""
}
if len(tailLog) == tail {
break
}
}
return tailLog, nil
}
// String converts a log line to a string for output given whether a detail
// bool is specified.
func (l *LogLine) String(options *LogOptions) string {
var out string
if options.Multi {
if options.UseName {
out = l.CName + " "
} else {
cid := l.CID
if len(cid) > 12 {
cid = cid[:12]
}
out = fmt.Sprintf("%s ", cid)
}
}
if options.Timestamps {
out += fmt.Sprintf("%s ", l.Time.Format(LogTimeFormat))
}
return out + l.Msg
}
// Since returns a bool as to whether a log line occurred after a given time
func (l *LogLine) Since(since time.Time) bool {
return l.Time.After(since)
}
// NewLogLine creates a logLine struct from a container log string
func NewLogLine(line string) (*LogLine, error) {
splitLine := strings.Split(line, " ")
if len(splitLine) < 4 {
return nil, errors.Errorf("'%s' is not a valid container log line", line)
}
logTime, err := time.Parse(LogTimeFormat, splitLine[0])
if err != nil {
return nil, errors.Wrapf(err, "unable to convert time %s from container log", splitLine[0])
}
l := LogLine{
Time: logTime,
Device: splitLine[1],
ParseLogType: splitLine[2],
Msg: strings.Join(splitLine[3:], " "),
}
return &l, nil
}
// Partial returns a bool if the log line is a partial log type
func (l *LogLine) Partial() bool {
return l.ParseLogType == PartialLogType
}
func (l *LogLine) Write(stdout io.Writer, stderr io.Writer, logOpts *LogOptions) {
switch l.Device {
case "stdout":
if stdout != nil {
fmt.Fprintln(stdout, l.String(logOpts))
}
case "stderr":
if stderr != nil {
fmt.Fprintln(stderr, l.String(logOpts))
}
default:
// Warn the user if the device type does not match. Most likely the file is corrupted.
logrus.Warnf("unknown Device type '%s' in log file from Container %s", l.Device, l.CID)
}
}
|
