package logrus import ( "bytes" "fmt" "os" "reflect" "runtime" "strings" "sync" "time" ) 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 // 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 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} } // 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} } // 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 { break } } return f } // getCaller retrieves the name of the first non-logrus calling function func getCaller() *runtime.Frame { // Restrict the lookback frames to avoid runaway lookups pcs := make([]uintptr, maximumCallerDepth) depth := runtime.Callers(minimumCallerDepth, pcs) frames := runtime.CallersFrames(pcs[:depth]) // cache this package's fully-qualified name callerInitOnce.Do(func() { logrusPackage = getPackageName(runtime.FuncForPC(pcs[0]).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 store an entry in a logger interface minimumCallerDepth = knownLogrusFrames }) 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() } entry.fireHooks() buffer = bufferPool.Get().(*bytes.Buffer) buffer.Reset() defer bufferPool.Put(buffer) entry.Buffer = buffer entry.write() 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 { panic(&entry) } } func (entry *Entry) fireHooks() { entry.Logger.mu.Lock() defer entry.Logger.mu.Unlock() 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() { entry.Logger.mu.Lock() defer entry.Logger.mu.Unlock() 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{}) { entry.Info(args...) } 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{}) { entry.Warn(args...) } func (entry *Entry) Error(args ...interface{}) { entry.Log(ErrorLevel, args...) } func (entry *Entry) Fatal(args ...interface{}) { entry.Log(FatalLevel, args...) entry.Logger.Exit(1) } func (entry *Entry) Panic(args ...interface{}) { entry.Log(PanicLevel, args...) panic(fmt.Sprint(args...)) } // Entry Printf family functions func (entry *Entry) Logf(level Level, format string, args ...interface{}) { 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...) entry.Logger.Exit(1) } 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{}) { entry.Infoln(args...) } func (entry *Entry) Warnln(args ...interface{}) { entry.Logln(WarnLevel, args...) } func (entry *Entry) Warningln(args ...interface{}) { entry.Warnln(args...) } func (entry *Entry) Errorln(args ...interface{}) { entry.Logln(ErrorLevel, args...) } func (entry *Entry) Fatalln(args ...interface{}) { entry.Logln(FatalLevel, args...) entry.Logger.Exit(1) } 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] }