in glog.go [671:740]
func (l *loggingT) output(s severity, buf *buffer, file string, line int, alsoToStderr bool) {
l.mu.Lock()
if l.traceLocation.isSet() {
if l.traceLocation.match(file, line) {
buf.Write(stacks(false))
}
}
data := buf.Bytes()
if !flag.Parsed() {
os.Stderr.Write([]byte("ERROR: logging before flag.Parse: "))
os.Stderr.Write(data)
} else if l.toStderr {
os.Stderr.Write(data)
} else {
if alsoToStderr || l.alsoToStderr || s >= l.stderrThreshold.get() {
os.Stderr.Write(data)
}
if l.file[s] == nil {
if err := l.createFiles(s); err != nil {
os.Stderr.Write(data) // Make sure the message appears somewhere.
l.exit(err)
}
}
switch s {
case fatalLog:
l.file[fatalLog].Write(data)
fallthrough
case errorLog:
l.file[errorLog].Write(data)
fallthrough
case warningLog:
l.file[warningLog].Write(data)
fallthrough
case infoLog:
l.file[infoLog].Write(data)
}
}
if s == fatalLog {
// If we got here via Exit rather than Fatal, print no stacks.
if atomic.LoadUint32(&fatalNoStacks) > 0 {
l.mu.Unlock()
timeoutFlush(10 * time.Second)
os.Exit(1)
}
// Dump all goroutine stacks before exiting.
// First, make sure we see the trace for the current goroutine on standard error.
// If -logtostderr has been specified, the loop below will do that anyway
// as the first stack in the full dump.
if !l.toStderr {
os.Stderr.Write(stacks(false))
}
// 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-- {
if f := l.file[log]; f != nil { // Can be nil if -logtostderr is set.
f.Write(trace)
}
}
l.mu.Unlock()
timeoutFlush(10 * time.Second)
os.Exit(255) // C++ uses -1, which is silly because it's anded with 255 anyway.
}
l.putBuffer(buf)
l.mu.Unlock()
if stats := severityStats[s]; stats != nil {
atomic.AddInt64(&stats.lines, 1)
atomic.AddInt64(&stats.bytes, int64(len(data)))
}
}