blob: 63e25583cb03f46285b4852f84d9e4d7e53c5d82 [file] [log] [blame]
package logrus
import (
var (
bufferPool *sync.Pool
// qualified package name, cached at first use
logrusPackage string
// Positions in the call stack when tracing to report the calling method
minimumCallerDepth int
// Used for caller information initialisation
callerInitOnce sync.Once
const (
maximumCallerDepth int = 25
knownLogrusFrames int = 4
func init() {
bufferPool = &sync.Pool{
New: func() interface{} {
return new(bytes.Buffer)
// start at the bottom of the stack before the package-name cache is primed
minimumCallerDepth = 1
// Defines the key when adding errors using WithError.
var ErrorKey = "error"
// An entry is the final or intermediate Logrus logging entry. It contains all
// the fields passed with WithField{,s}. It's finally logged when Trace, Debug,
// Info, Warn, Error, Fatal or Panic is called on it. These objects can be
// reused and passed around as much as you wish to avoid field duplication.
type Entry struct {
Logger *Logger
// Contains all the fields set by the user.
Data Fields
// Time at which the log entry was created
Time time.Time
// Level the log entry was logged at: Trace, Debug, Info, Warn, Error, Fatal or Panic
// This field will be set on entry firing and the value will be equal to the one in Logger struct field.
Level Level
// Calling method, with package name
Caller *runtime.Frame
// Message passed to Trace, Debug, Info, Warn, Error, Fatal or Panic
Message string
// When formatter is called in entry.log(), a Buffer may be set to entry
Buffer *bytes.Buffer
// Contains the context set by the user. Useful for hook processing etc.
Context context.Context
// err may contain a field formatting error
err string
func NewEntry(logger *Logger) *Entry {
return &Entry{
Logger: logger,
// Default is three fields, plus one optional. Give a little extra room.
Data: make(Fields, 6),
// Returns the string representation from the reader and ultimately the
// formatter.
func (entry *Entry) String() (string, error) {
serialized, err := entry.Logger.Formatter.Format(entry)
if err != nil {
return "", err
str := string(serialized)
return str, nil
// Add an error as single field (using the key defined in ErrorKey) to the Entry.
func (entry *Entry) WithError(err error) *Entry {
return entry.WithField(ErrorKey, err)
// Add a context to the Entry.
func (entry *Entry) WithContext(ctx context.Context) *Entry {
return &Entry{Logger: entry.Logger, Data: entry.Data, Time: entry.Time, err: entry.err, Context: ctx}
// Add a single field to the Entry.
func (entry *Entry) WithField(key string, value interface{}) *Entry {
return entry.WithFields(Fields{key: value})
// Add a map of fields to the Entry.
func (entry *Entry) WithFields(fields Fields) *Entry {
data := make(Fields, len(entry.Data)+len(fields))
for k, v := range entry.Data {
data[k] = v
fieldErr := entry.err
for k, v := range fields {
isErrField := false
if t := reflect.TypeOf(v); t != nil {
switch t.Kind() {
case reflect.Func:
isErrField = true
case reflect.Ptr:
isErrField = t.Elem().Kind() == reflect.Func
if isErrField {
tmp := fmt.Sprintf("can not add field %q", k)
if fieldErr != "" {
fieldErr = entry.err + ", " + tmp
} else {
fieldErr = tmp
} else {
data[k] = v
return &Entry{Logger: entry.Logger, Data: data, Time: entry.Time, err: fieldErr, Context: entry.Context}
// Overrides the time of the Entry.
func (entry *Entry) WithTime(t time.Time) *Entry {
return &Entry{Logger: entry.Logger, Data: entry.Data, Time: t, err: entry.err, Context: entry.Context}
// getPackageName reduces a fully qualified function name to the package name
// There really ought to be to be a better way...
func getPackageName(f string) string {
for {
lastPeriod := strings.LastIndex(f, ".")
lastSlash := strings.LastIndex(f, "/")
if lastPeriod > lastSlash {
f = f[:lastPeriod]
} else {
return f
// getCaller retrieves the name of the first non-logrus calling function
func getCaller() *runtime.Frame {
// cache this package's fully-qualified name
callerInitOnce.Do(func() {
pcs := make([]uintptr, 2)
_ = runtime.Callers(0, pcs)
logrusPackage = getPackageName(runtime.FuncForPC(pcs[1]).Name())
// now that we have the cache, we can skip a minimum count of known-logrus functions
// XXX this is dubious, the number of frames may vary
minimumCallerDepth = knownLogrusFrames
// Restrict the lookback frames to avoid runaway lookups
pcs := make([]uintptr, maximumCallerDepth)
depth := runtime.Callers(minimumCallerDepth, pcs)
frames := runtime.CallersFrames(pcs[:depth])
for f, again := frames.Next(); again; f, again = frames.Next() {
pkg := getPackageName(f.Function)
// If the caller isn't part of this package, we're done
if pkg != logrusPackage {
return &f
// if we got here, we failed to find the caller's context
return nil
func (entry Entry) HasCaller() (has bool) {
return entry.Logger != nil &&
entry.Logger.ReportCaller &&
entry.Caller != nil
// This function is not declared with a pointer value because otherwise
// race conditions will occur when using multiple goroutines
func (entry Entry) log(level Level, msg string) {
var buffer *bytes.Buffer
// Default to now, but allow users to override if they want.
// We don't have to worry about polluting future calls to Entry#log()
// with this assignment because this function is declared with a
// non-pointer receiver.
if entry.Time.IsZero() {
entry.Time = time.Now()
entry.Level = level
entry.Message = msg
if entry.Logger.ReportCaller {
entry.Caller = getCaller()
buffer = bufferPool.Get().(*bytes.Buffer)
defer bufferPool.Put(buffer)
entry.Buffer = buffer
entry.Buffer = nil
// To avoid Entry#log() returning a value that only would make sense for
// panic() to use in Entry#Panic(), we avoid the allocation by checking
// directly here.
if level <= PanicLevel {
func (entry *Entry) fireHooks() {
err := entry.Logger.Hooks.Fire(entry.Level, entry)
if err != nil {
fmt.Fprintf(os.Stderr, "Failed to fire hook: %v\n", err)
func (entry *Entry) write() {
serialized, err := entry.Logger.Formatter.Format(entry)
if err != nil {
fmt.Fprintf(os.Stderr, "Failed to obtain reader, %v\n", err)
} else {
_, err = entry.Logger.Out.Write(serialized)
if err != nil {
fmt.Fprintf(os.Stderr, "Failed to write to log, %v\n", err)
func (entry *Entry) Log(level Level, args ...interface{}) {
if entry.Logger.IsLevelEnabled(level) {
entry.log(level, fmt.Sprint(args...))
func (entry *Entry) Trace(args ...interface{}) {
entry.Log(TraceLevel, args...)
func (entry *Entry) Debug(args ...interface{}) {
entry.Log(DebugLevel, args...)
func (entry *Entry) Print(args ...interface{}) {
func (entry *Entry) Info(args ...interface{}) {
entry.Log(InfoLevel, args...)
func (entry *Entry) Warn(args ...interface{}) {
entry.Log(WarnLevel, args...)
func (entry *Entry) Warning(args ...interface{}) {
func (entry *Entry) Error(args ...interface{}) {
entry.Log(ErrorLevel, args...)
func (entry *Entry) Fatal(args ...interface{}) {
entry.Log(FatalLevel, args...)
func (entry *Entry) Panic(args ...interface{}) {
entry.Log(PanicLevel, args...)
// Entry Printf family functions
func (entry *Entry) Logf(level Level, format string, args ...interface{}) {
if entry.Logger.IsLevelEnabled(level) {
entry.Log(level, fmt.Sprintf(format, args...))
func (entry *Entry) Tracef(format string, args ...interface{}) {
entry.Logf(TraceLevel, format, args...)
func (entry *Entry) Debugf(format string, args ...interface{}) {
entry.Logf(DebugLevel, format, args...)
func (entry *Entry) Infof(format string, args ...interface{}) {
entry.Logf(InfoLevel, format, args...)
func (entry *Entry) Printf(format string, args ...interface{}) {
entry.Infof(format, args...)
func (entry *Entry) Warnf(format string, args ...interface{}) {
entry.Logf(WarnLevel, format, args...)
func (entry *Entry) Warningf(format string, args ...interface{}) {
entry.Warnf(format, args...)
func (entry *Entry) Errorf(format string, args ...interface{}) {
entry.Logf(ErrorLevel, format, args...)
func (entry *Entry) Fatalf(format string, args ...interface{}) {
entry.Logf(FatalLevel, format, args...)
func (entry *Entry) Panicf(format string, args ...interface{}) {
entry.Logf(PanicLevel, format, args...)
// Entry Println family functions
func (entry *Entry) Logln(level Level, args ...interface{}) {
if entry.Logger.IsLevelEnabled(level) {
entry.Log(level, entry.sprintlnn(args...))
func (entry *Entry) Traceln(args ...interface{}) {
entry.Logln(TraceLevel, args...)
func (entry *Entry) Debugln(args ...interface{}) {
entry.Logln(DebugLevel, args...)
func (entry *Entry) Infoln(args ...interface{}) {
entry.Logln(InfoLevel, args...)
func (entry *Entry) Println(args ...interface{}) {
func (entry *Entry) Warnln(args ...interface{}) {
entry.Logln(WarnLevel, args...)
func (entry *Entry) Warningln(args ...interface{}) {
func (entry *Entry) Errorln(args ...interface{}) {
entry.Logln(ErrorLevel, args...)
func (entry *Entry) Fatalln(args ...interface{}) {
entry.Logln(FatalLevel, args...)
func (entry *Entry) Panicln(args ...interface{}) {
entry.Logln(PanicLevel, args...)
// Sprintlnn => Sprint no newline. This is to get the behavior of how
// fmt.Sprintln where spaces are always added between operands, regardless of
// their type. Instead of vendoring the Sprintln implementation to spare a
// string allocation, we do the simplest thing.
func (entry *Entry) sprintlnn(args ...interface{}) string {
msg := fmt.Sprintln(args...)
return msg[:len(msg)-1]