telegraf/logger/logger.go

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package logger
import (
"io"
"log"
"os"
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"regexp"
"time"
"github.com/influxdata/wlog"
)
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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) {
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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 != "" {
if _, err := os.Stat(logfile); os.IsNotExist(err) {
if oFile, err = os.Create(logfile); err != nil {
log.Printf("E! Unable to create %s (%s), using stderr", logfile, err)
oFile = os.Stderr
}
} else {
if oFile, err = os.OpenFile(logfile, os.O_APPEND|os.O_WRONLY, os.ModeAppend); err != nil {
log.Printf("E! Unable to append to %s (%s), using stderr", logfile, err)
oFile = os.Stderr
}
}
} else {
oFile = os.Stderr
}
log.SetOutput(newTelegrafWriter(oFile))
}