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}) 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} close(inputs) break } logrus.Error(err) close(inputs) } 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 loglines, we can hangup if nllCounter >= tail { if err := f.Close(); err != nil { logrus.Error(err) } 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 logline 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 }