package logger import ( "io" "log" "os" "regexp" "time" "github.com/influxdata/wlog" ) var prefixRegex = regexp.MustCompile("^[DIWE]!") // newTelegrafWriter returns a logging-wrapped writer. func newTelegrafWriter(w io.Writer) io.Writer { return &telegrafLog{ writer: wlog.NewWriter(w), } } type telegrafLog struct { writer io.Writer } func (t *telegrafLog) Write(b []byte) (n int, err error) { var line []byte if !prefixRegex.Match(b) { line = append([]byte(time.Now().UTC().Format(time.RFC3339)+" I! "), b...) } else { line = append([]byte(time.Now().UTC().Format(time.RFC3339)+" "), b...) } return t.writer.Write(line) } // SetupLogging configures the logging output. // debug will set the log level to DEBUG // quiet will set the log level to ERROR // logfile will direct the logging output to a file. Empty string is // interpreted as stderr. If there is an error opening the file the // logger will fallback to stderr. func SetupLogging(debug, quiet bool, logfile string) { log.SetFlags(0) if debug { wlog.SetLevel(wlog.DEBUG) } if quiet { wlog.SetLevel(wlog.ERROR) } var oFile *os.File if logfile != "" { var err error if oFile, err = os.OpenFile(logfile, os.O_CREATE|os.O_APPEND|os.O_WRONLY, os.ModeAppend|0644); err != nil { log.Printf("E! Unable to open %s (%s), using stderr", logfile, err) oFile = os.Stderr } } else { oFile = os.Stderr } log.SetOutput(newTelegrafWriter(oFile)) }