add debug level for glog

glog.go

@@ -98,16 +98,18 @@ type severity int32 // sync/atomic int32
 // A message written to a high-severity log file is also written to each
 // lower-severity log file.
 const (
-	infoLog severity = iota
+	debugLog severity = iota
+	infoLog
 	warningLog
 	errorLog
 	fatalLog
-	numSeverity = 4
+	numSeverity = 5
 )
 
-const severityChar = "IWEF"
+const severityChar = "DIWEF"
 
 var severityName = []string{
+	debugLog:   "DEBUG",
 	infoLog:    "INFO",
 	warningLog: "WARNING",
 	errorLog:   "ERROR",
@@ -180,10 +182,11 @@ func (s *OutputStats) Bytes() int64 {
 // Stats tracks the number of lines of output and number of bytes
 // per severity level. Values must be read with atomic.LoadInt64.
 var Stats struct {
-	Info, Warning, Error OutputStats
+	Debug, Info, Warning, Error OutputStats
 }
 
 var severityStats = [numSeverity]*OutputStats{
+	debugLog:   &Stats.Debug,
 	infoLog:    &Stats.Info,
 	warningLog: &Stats.Warning,
 	errorLog:   &Stats.Error,
@@ -703,6 +706,8 @@ func (l *loggingT) output(s severity, buf *buffer, file string, line int, alsoTo
 			fallthrough
 		case infoLog:
 			l.file[infoLog].Write(data)
+		case debugLog:
+			l.file[debugLog].Write(data)
 		}
 	}
 	if s == fatalLog {
@@ -722,7 +727,7 @@ func (l *loggingT) output(s severity, buf *buffer, file string, line int, alsoTo
 		// Write the stack trace for all goroutines to the files.
 		trace := stacks(true)
 		logExitFunc = func(error) {} // If we get a write error, we'll still exit below.
-		for log := fatalLog; log >= infoLog; log-- {
+		for log := fatalLog; log >= debugLog; log-- {
 			if f := l.file[log]; f != nil { // Can be nil if -logtostderr is set.
 				f.Write(trace)
 			}
@@ -862,7 +867,7 @@ func (l *loggingT) createFiles(sev severity) error {
 	now := time.Now()
 	// Files are created in decreasing severity order, so as soon as we find one
 	// has already been created, we can stop.
-	for s := sev; s >= infoLog && l.file[s] == nil; s-- {
+	for s := sev; s >= debugLog && l.file[s] == nil; s-- {
 		sb := &syncBuffer{
 			logger: l,
 			sev:    s,
@@ -895,7 +900,7 @@ func (l *loggingT) lockAndFlushAll() {
 // l.mu is held.
 func (l *loggingT) flushAll() {
 	// Flush from fatal down, in case there's trouble flushing.
-	for s := fatalLog; s >= infoLog; s-- {
+	for s := fatalLog; s >= debugLog; s-- {
 		file := l.file[s]
 		if file != nil {
 			file.Flush() // ignore error
@@ -1049,6 +1054,22 @@ func (v Verbose) Infof(format string, args ...interface{}) {
 	}
 }
 
+func Debug(args ...interface{}) {
+	logging.print(debugLog, args...)
+}
+
+func DebugDepth(depth int, args ...interface{}) {
+	logging.printDepth(debugLog, depth, args...)
+}
+
+func Debugln(args ...interface{}) {
+	logging.println(debugLog, args...)
+}
+
+func Debugf(format string, args ...interface{}) {
+	logging.printf(debugLog, format, args...)
+}
+
 // Info logs to the INFO log.
 // Arguments are handled in the manner of fmt.Print; a newline is appended if missing.
 func Info(args ...interface{}) {