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Package logrus

import "github.com/Sirupsen/logrus"
Overview
Index
Subdirectories

Overview ▾

Package logrus is a structured logger for Go, completely API compatible with the standard library logger.

The simplest way to use Logrus is simply the package-level exported logger:

package main

import (
  log "github.com/Sirupsen/logrus"
)

func main() {
  log.WithFields(log.Fields{
    "animal": "walrus",
    "number": 1,
    "size":   10,
  }).Info("A walrus appears")
}

Output:

time="2015-09-07T08:48:33Z" level=info msg="A walrus appears" animal=walrus number=1 size=10

For a full guide visit https://github.com/Sirupsen/logrus

Index ▾

Constants
Variables
func AddHook(hook Hook)
func Debug(args ...interface{})
func Debugf(format string, args ...interface{})
func Debugln(args ...interface{})
func Error(args ...interface{})
func Errorf(format string, args ...interface{})
func Errorln(args ...interface{})
func Exit(code int)
func Fatal(args ...interface{})
func Fatalf(format string, args ...interface{})
func Fatalln(args ...interface{})
func Info(args ...interface{})
func Infof(format string, args ...interface{})
func Infoln(args ...interface{})
func IsTerminal() bool
func Panic(args ...interface{})
func Panicf(format string, args ...interface{})
func Panicln(args ...interface{})
func Print(args ...interface{})
func Printf(format string, args ...interface{})
func Println(args ...interface{})
func RegisterExitHandler(handler func())
func SetFormatter(formatter Formatter)
func SetLevel(level Level)
func SetOutput(out io.Writer)
func Warn(args ...interface{})
func Warnf(format string, args ...interface{})
func Warning(args ...interface{})
func Warningf(format string, args ...interface{})
func Warningln(args ...interface{})
func Warnln(args ...interface{})
type Entry
    func NewEntry(logger *Logger) *Entry
    func WithError(err error) *Entry
    func WithField(key string, value interface{}) *Entry
    func WithFields(fields Fields) *Entry
    func (entry *Entry) Debug(args ...interface{})
    func (entry *Entry) Debugf(format string, args ...interface{})
    func (entry *Entry) Debugln(args ...interface{})
    func (entry *Entry) Error(args ...interface{})
    func (entry *Entry) Errorf(format string, args ...interface{})
    func (entry *Entry) Errorln(args ...interface{})
    func (entry *Entry) Fatal(args ...interface{})
    func (entry *Entry) Fatalf(format string, args ...interface{})
    func (entry *Entry) Fatalln(args ...interface{})
    func (entry *Entry) Info(args ...interface{})
    func (entry *Entry) Infof(format string, args ...interface{})
    func (entry *Entry) Infoln(args ...interface{})
    func (entry *Entry) Panic(args ...interface{})
    func (entry *Entry) Panicf(format string, args ...interface{})
    func (entry *Entry) Panicln(args ...interface{})
    func (entry *Entry) Print(args ...interface{})
    func (entry *Entry) Printf(format string, args ...interface{})
    func (entry *Entry) Println(args ...interface{})
    func (entry *Entry) Reader() (*bytes.Buffer, error)
    func (entry *Entry) String() (string, error)
    func (entry *Entry) Warn(args ...interface{})
    func (entry *Entry) Warnf(format string, args ...interface{})
    func (entry *Entry) Warning(args ...interface{})
    func (entry *Entry) Warningf(format string, args ...interface{})
    func (entry *Entry) Warningln(args ...interface{})
    func (entry *Entry) Warnln(args ...interface{})
    func (entry *Entry) WithError(err error) *Entry
    func (entry *Entry) WithField(key string, value interface{}) *Entry
    func (entry *Entry) WithFields(fields Fields) *Entry
type FieldLogger
type Fields
type Formatter
type Hook
type JSONFormatter
    func (f *JSONFormatter) Format(entry *Entry) ([]byte, error)
type Level
    func GetLevel() Level
    func ParseLevel(lvl string) (Level, error)
    func (level Level) String() string
type LevelHooks
    func (hooks LevelHooks) Add(hook Hook)
    func (hooks LevelHooks) Fire(level Level, entry *Entry) error
type Logger
    func New() *Logger
    func StandardLogger() *Logger
    func (logger *Logger) Debug(args ...interface{})
    func (logger *Logger) Debugf(format string, args ...interface{})
    func (logger *Logger) Debugln(args ...interface{})
    func (logger *Logger) Error(args ...interface{})
    func (logger *Logger) Errorf(format string, args ...interface{})
    func (logger *Logger) Errorln(args ...interface{})
    func (logger *Logger) Fatal(args ...interface{})
    func (logger *Logger) Fatalf(format string, args ...interface{})
    func (logger *Logger) Fatalln(args ...interface{})
    func (logger *Logger) Info(args ...interface{})
    func (logger *Logger) Infof(format string, args ...interface{})
    func (logger *Logger) Infoln(args ...interface{})
    func (logger *Logger) Panic(args ...interface{})
    func (logger *Logger) Panicf(format string, args ...interface{})
    func (logger *Logger) Panicln(args ...interface{})
    func (logger *Logger) Print(args ...interface{})
    func (logger *Logger) Printf(format string, args ...interface{})
    func (logger *Logger) Println(args ...interface{})
    func (logger *Logger) Warn(args ...interface{})
    func (logger *Logger) Warnf(format string, args ...interface{})
    func (logger *Logger) Warning(args ...interface{})
    func (logger *Logger) Warningf(format string, args ...interface{})
    func (logger *Logger) Warningln(args ...interface{})
    func (logger *Logger) Warnln(args ...interface{})
    func (logger *Logger) WithError(err error) *Entry
    func (logger *Logger) WithField(key string, value interface{}) *Entry
    func (logger *Logger) WithFields(fields Fields) *Entry
    func (logger *Logger) Writer() *io.PipeWriter
    func (logger *Logger) WriterLevel(level Level) *io.PipeWriter
type StdLogger
type Termios
type TextFormatter
    func (f *TextFormatter) Format(entry *Entry) ([]byte, error)

Package files

alt_exit.go doc.go entry.go exported.go formatter.go hooks.go json_formatter.go logger.go logrus.go terminal_linux.go terminal_notwindows.go text_formatter.go writer.go

Constants

const DefaultTimestampFormat = time.RFC3339

Variables

var AllLevels = []Level{
    PanicLevel,
    FatalLevel,
    ErrorLevel,
    WarnLevel,
    InfoLevel,
    DebugLevel,
}

A constant exposing all logging levels

var ErrorKey = "error"

Defines the key when adding errors using WithError.

func AddHook

func AddHook(hook Hook)

AddHook adds a hook to the standard logger hooks.

func Debug

func Debug(args ...interface{})

Debug logs a message at level Debug on the standard logger.

func Debugf

func Debugf(format string, args ...interface{})

Debugf logs a message at level Debug on the standard logger.

func Debugln

func Debugln(args ...interface{})

Debugln logs a message at level Debug on the standard logger.

func Error

func Error(args ...interface{})

Error logs a message at level Error on the standard logger.

func Errorf

func Errorf(format string, args ...interface{})

Errorf logs a message at level Error on the standard logger.

func Errorln

func Errorln(args ...interface{})

Errorln logs a message at level Error on the standard logger.

func Exit

func Exit(code int)

Exit runs all the Logrus atexit handlers and then terminates the program using os.Exit(code)

func Fatal

func Fatal(args ...interface{})

Fatal logs a message at level Fatal on the standard logger.

func Fatalf

func Fatalf(format string, args ...interface{})

Fatalf logs a message at level Fatal on the standard logger.

func Fatalln

func Fatalln(args ...interface{})

Fatalln logs a message at level Fatal on the standard logger.

func Info

func Info(args ...interface{})

Info logs a message at level Info on the standard logger.

func Infof

func Infof(format string, args ...interface{})

Infof logs a message at level Info on the standard logger.

func Infoln

func Infoln(args ...interface{})

Infoln logs a message at level Info on the standard logger.

func IsTerminal

func IsTerminal() bool

IsTerminal returns true if stderr's file descriptor is a terminal.

func Panic

func Panic(args ...interface{})

Panic logs a message at level Panic on the standard logger.

func Panicf

func Panicf(format string, args ...interface{})

Panicf logs a message at level Panic on the standard logger.

func Panicln

func Panicln(args ...interface{})

Panicln logs a message at level Panic on the standard logger.

func Print

func Print(args ...interface{})

Print logs a message at level Info on the standard logger.

func Printf

func Printf(format string, args ...interface{})

Printf logs a message at level Info on the standard logger.

func Println

func Println(args ...interface{})

Println logs a message at level Info on the standard logger.

func RegisterExitHandler

func RegisterExitHandler(handler func())

RegisterExitHandler adds a Logrus Exit handler, call logrus.Exit to invoke all handlers. The handlers will also be invoked when any Fatal log entry is made.

This method is useful when a caller wishes to use logrus to log a fatal message but also needs to gracefully shutdown. An example usecase could be closing database connections, or sending a alert that the application is closing.

func SetFormatter

func SetFormatter(formatter Formatter)

SetFormatter sets the standard logger formatter.

func SetLevel

func SetLevel(level Level)

SetLevel sets the standard logger level.

func SetOutput

func SetOutput(out io.Writer)

SetOutput sets the standard logger output.

func Warn

func Warn(args ...interface{})

Warn logs a message at level Warn on the standard logger.

func Warnf

func Warnf(format string, args ...interface{})

Warnf logs a message at level Warn on the standard logger.

func Warning

func Warning(args ...interface{})

Warning logs a message at level Warn on the standard logger.

func Warningf

func Warningf(format string, args ...interface{})

Warningf logs a message at level Warn on the standard logger.

func Warningln

func Warningln(args ...interface{})

Warningln logs a message at level Warn on the standard logger.

func Warnln

func Warnln(args ...interface{})

Warnln logs a message at level Warn on the standard logger.

type Entry

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: Debug, Info, Warn, Error, Fatal or Panic
    Level Level

    // Message passed to Debug, Info, Warn, Error, Fatal or Panic
    Message string
}

An entry is the final or intermediate Logrus logging entry. It contains all the fields passed with WithField{,s}. It's finally logged when 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.

func NewEntry

func NewEntry(logger *Logger) *Entry

func WithError

func WithError(err error) *Entry

WithError creates an entry from the standard logger and adds an error to it, using the value defined in ErrorKey as key.

func WithField

func WithField(key string, value interface{}) *Entry

WithField creates an entry from the standard logger and adds a field to it. If you want multiple fields, use `WithFields`.

Note that it doesn't log until you call Debug, Print, Info, Warn, Fatal or Panic on the Entry it returns.

func WithFields

func WithFields(fields Fields) *Entry

WithFields creates an entry from the standard logger and adds multiple fields to it. This is simply a helper for `WithField`, invoking it once for each field.

Note that it doesn't log until you call Debug, Print, Info, Warn, Fatal or Panic on the Entry it returns.

func (*Entry) Debug

func (entry *Entry) Debug(args ...interface{})

func (*Entry) Debugf

func (entry *Entry) Debugf(format string, args ...interface{})

func (*Entry) Debugln

func (entry *Entry) Debugln(args ...interface{})

func (*Entry) Error

func (entry *Entry) Error(args ...interface{})

func (*Entry) Errorf

func (entry *Entry) Errorf(format string, args ...interface{})

func (*Entry) Errorln

func (entry *Entry) Errorln(args ...interface{})

func (*Entry) Fatal

func (entry *Entry) Fatal(args ...interface{})

func (*Entry) Fatalf

func (entry *Entry) Fatalf(format string, args ...interface{})

func (*Entry) Fatalln

func (entry *Entry) Fatalln(args ...interface{})

func (*Entry) Info

func (entry *Entry) Info(args ...interface{})

func (*Entry) Infof

func (entry *Entry) Infof(format string, args ...interface{})

func (*Entry) Infoln

func (entry *Entry) Infoln(args ...interface{})

func (*Entry) Panic

func (entry *Entry) Panic(args ...interface{})

func (*Entry) Panicf

func (entry *Entry) Panicf(format string, args ...interface{})

func (*Entry) Panicln

func (entry *Entry) Panicln(args ...interface{})

func (*Entry) Print

func (entry *Entry) Print(args ...interface{})

func (*Entry) Printf

func (entry *Entry) Printf(format string, args ...interface{})

func (*Entry) Println

func (entry *Entry) Println(args ...interface{})

func (*Entry) Reader

func (entry *Entry) Reader() (*bytes.Buffer, error)

Returns a reader for the entry, which is a proxy to the formatter.

func (*Entry) String

func (entry *Entry) String() (string, error)

Returns the string representation from the reader and ultimately the formatter.

func (*Entry) Warn

func (entry *Entry) Warn(args ...interface{})

func (*Entry) Warnf

func (entry *Entry) Warnf(format string, args ...interface{})

func (*Entry) Warning

func (entry *Entry) Warning(args ...interface{})

func (*Entry) Warningf

func (entry *Entry) Warningf(format string, args ...interface{})

func (*Entry) Warningln

func (entry *Entry) Warningln(args ...interface{})

func (*Entry) Warnln

func (entry *Entry) Warnln(args ...interface{})

func (*Entry) WithError

func (entry *Entry) WithError(err error) *Entry

Add an error as single field (using the key defined in ErrorKey) to the Entry.

func (*Entry) WithField

func (entry *Entry) WithField(key string, value interface{}) *Entry

Add a single field to the Entry.

func (*Entry) WithFields

func (entry *Entry) WithFields(fields Fields) *Entry

Add a map of fields to the Entry.

type FieldLogger

type FieldLogger interface {
    WithField(key string, value interface{}) *Entry
    WithFields(fields Fields) *Entry
    WithError(err error) *Entry

    Debugf(format string, args ...interface{})
    Infof(format string, args ...interface{})
    Printf(format string, args ...interface{})
    Warnf(format string, args ...interface{})
    Warningf(format string, args ...interface{})
    Errorf(format string, args ...interface{})
    Fatalf(format string, args ...interface{})
    Panicf(format string, args ...interface{})

    Debug(args ...interface{})
    Info(args ...interface{})
    Print(args ...interface{})
    Warn(args ...interface{})
    Warning(args ...interface{})
    Error(args ...interface{})
    Fatal(args ...interface{})
    Panic(args ...interface{})

    Debugln(args ...interface{})
    Infoln(args ...interface{})
    Println(args ...interface{})
    Warnln(args ...interface{})
    Warningln(args ...interface{})
    Errorln(args ...interface{})
    Fatalln(args ...interface{})
    Panicln(args ...interface{})
}

The FieldLogger interface generalizes the Entry and Logger types

type Fields

type Fields map[string]interface{}

Fields type, used to pass to `WithFields`.

type Formatter

type Formatter interface {
    Format(*Entry) ([]byte, error)
}

The Formatter interface is used to implement a custom Formatter. It takes an `Entry`. It exposes all the fields, including the default ones:

* `entry.Data["msg"]`. The message passed from Info, Warn, Error .. * `entry.Data["time"]`. The timestamp. * `entry.Data["level"]. The level the entry was logged at.

Any additional fields added with `WithField` or `WithFields` are also in `entry.Data`. Format is expected to return an array of bytes which are then logged to `logger.Out`.

type Hook

type Hook interface {
    Levels() []Level
    Fire(*Entry) error
}

A hook to be fired when logging on the logging levels returned from `Levels()` on your implementation of the interface. Note that this is not fired in a goroutine or a channel with workers, you should handle such functionality yourself if your call is non-blocking and you don't wish for the logging calls for levels returned from `Levels()` to block.

type JSONFormatter

type JSONFormatter struct {
    // TimestampFormat sets the format used for marshaling timestamps.
    TimestampFormat string
}

func (*JSONFormatter) Format

func (f *JSONFormatter) Format(entry *Entry) ([]byte, error)

type Level

type Level uint8

Level type

const (
    // PanicLevel level, highest level of severity. Logs and then calls panic with the
    // message passed to Debug, Info, ...
    PanicLevel Level = iota
    // FatalLevel level. Logs and then calls `os.Exit(1)`. It will exit even if the
    // logging level is set to Panic.
    FatalLevel
    // ErrorLevel level. Logs. Used for errors that should definitely be noted.
    // Commonly used for hooks to send errors to an error tracking service.
    ErrorLevel
    // WarnLevel level. Non-critical entries that deserve eyes.
    WarnLevel
    // InfoLevel level. General operational entries about what's going on inside the
    // application.
    InfoLevel
    // DebugLevel level. Usually only enabled when debugging. Very verbose logging.
    DebugLevel
)

These are the different logging levels. You can set the logging level to log on your instance of logger, obtained with `logrus.New()`.

func GetLevel

func GetLevel() Level

GetLevel returns the standard logger level.

func ParseLevel

func ParseLevel(lvl string) (Level, error)

ParseLevel takes a string level and returns the Logrus log level constant.

func (Level) String

func (level Level) String() string

Convert the Level to a string. E.g. PanicLevel becomes "panic".

type LevelHooks

type LevelHooks map[Level][]Hook

Internal type for storing the hooks on a logger instance.

func (LevelHooks) Add

func (hooks LevelHooks) Add(hook Hook)

Add a hook to an instance of logger. This is called with `log.Hooks.Add(new(MyHook))` where `MyHook` implements the `Hook` interface.

func (LevelHooks) Fire

func (hooks LevelHooks) Fire(level Level, entry *Entry) error

Fire all the hooks for the passed level. Used by `entry.log` to fire appropriate hooks for a log entry.

type Logger

type Logger struct {
    // The logs are `io.Copy`'d to this in a mutex. It's common to set this to a
    // file, or leave it default which is `os.Stderr`. You can also set this to
    // something more adventorous, such as logging to Kafka.
    Out io.Writer
    // Hooks for the logger instance. These allow firing events based on logging
    // levels and log entries. For example, to send errors to an error tracking
    // service, log to StatsD or dump the core on fatal errors.
    Hooks LevelHooks
    // All log entries pass through the formatter before logged to Out. The
    // included formatters are `TextFormatter` and `JSONFormatter` for which
    // TextFormatter is the default. In development (when a TTY is attached) it
    // logs with colors, but to a file it wouldn't. You can easily implement your
    // own that implements the `Formatter` interface, see the `README` or included
    // formatters for examples.
    Formatter Formatter
    // The logging level the logger should log at. This is typically (and defaults
    // to) `logrus.Info`, which allows Info(), Warn(), Error() and Fatal() to be
    // logged. `logrus.Debug` is useful in
    Level Level
    // contains filtered or unexported fields
}

func New

func New() *Logger

Creates a new logger. Configuration should be set by changing `Formatter`, `Out` and `Hooks` directly on the default logger instance. You can also just instantiate your own:

var log = &Logger{
  Out: os.Stderr,
  Formatter: new(JSONFormatter),
  Hooks: make(LevelHooks),
  Level: logrus.DebugLevel,
}

It's recommended to make this a global instance called `log`.

func StandardLogger

func StandardLogger() *Logger

func (*Logger) Debug

func (logger *Logger) Debug(args ...interface{})

func (*Logger) Debugf

func (logger *Logger) Debugf(format string, args ...interface{})

func (*Logger) Debugln

func (logger *Logger) Debugln(args ...interface{})

func (*Logger) Error

func (logger *Logger) Error(args ...interface{})

func (*Logger) Errorf

func (logger *Logger) Errorf(format string, args ...interface{})

func (*Logger) Errorln

func (logger *Logger) Errorln(args ...interface{})

func (*Logger) Fatal

func (logger *Logger) Fatal(args ...interface{})

func (*Logger) Fatalf

func (logger *Logger) Fatalf(format string, args ...interface{})

func (*Logger) Fatalln

func (logger *Logger) Fatalln(args ...interface{})

func (*Logger) Info

func (logger *Logger) Info(args ...interface{})

func (*Logger) Infof

func (logger *Logger) Infof(format string, args ...interface{})

func (*Logger) Infoln

func (logger *Logger) Infoln(args ...interface{})

func (*Logger) Panic

func (logger *Logger) Panic(args ...interface{})

func (*Logger) Panicf

func (logger *Logger) Panicf(format string, args ...interface{})

func (*Logger) Panicln

func (logger *Logger) Panicln(args ...interface{})

func (*Logger) Print

func (logger *Logger) Print(args ...interface{})

func (*Logger) Printf

func (logger *Logger) Printf(format string, args ...interface{})

func (*Logger) Println

func (logger *Logger) Println(args ...interface{})

func (*Logger) Warn

func (logger *Logger) Warn(args ...interface{})

func (*Logger) Warnf

func (logger *Logger) Warnf(format string, args ...interface{})

func (*Logger) Warning

func (logger *Logger) Warning(args ...interface{})

func (*Logger) Warningf

func (logger *Logger) Warningf(format string, args ...interface{})

func (*Logger) Warningln

func (logger *Logger) Warningln(args ...interface{})

func (*Logger) Warnln

func (logger *Logger) Warnln(args ...interface{})

func (*Logger) WithError

func (logger *Logger) WithError(err error) *Entry

Add an error as single field to the log entry. All it does is call `WithError` for the given `error`.

func (*Logger) WithField

func (logger *Logger) WithField(key string, value interface{}) *Entry

Adds a field to the log entry, note that it doesn't log until you call Debug, Print, Info, Warn, Fatal or Panic. It only creates a log entry. If you want multiple fields, use `WithFields`.

func (*Logger) WithFields

func (logger *Logger) WithFields(fields Fields) *Entry

Adds a struct of fields to the log entry. All it does is call `WithField` for each `Field`.

func (*Logger) Writer

func (logger *Logger) Writer() *io.PipeWriter

func (*Logger) WriterLevel

func (logger *Logger) WriterLevel(level Level) *io.PipeWriter

type StdLogger

type StdLogger interface {
    Print(...interface{})
    Printf(string, ...interface{})
    Println(...interface{})

    Fatal(...interface{})
    Fatalf(string, ...interface{})
    Fatalln(...interface{})

    Panic(...interface{})
    Panicf(string, ...interface{})
    Panicln(...interface{})
}

StdLogger is what your logrus-enabled library should take, that way it'll accept a stdlib logger and a logrus logger. There's no standard interface, this is the closest we get, unfortunately.

type Termios

type Termios syscall.Termios

type TextFormatter

type TextFormatter struct {
    // Set to true to bypass checking for a TTY before outputting colors.
    ForceColors bool

    // Force disabling colors.
    DisableColors bool

    // Disable timestamp logging. useful when output is redirected to logging
    // system that already adds timestamps.
    DisableTimestamp bool

    // Enable logging the full timestamp when a TTY is attached instead of just
    // the time passed since beginning of execution.
    FullTimestamp bool

    // TimestampFormat to use for display when a full timestamp is printed
    TimestampFormat string

    // The fields are sorted by default for a consistent output. For applications
    // that log extremely frequently and don't use the JSON formatter this may not
    // be desired.
    DisableSorting bool
}

func (*TextFormatter) Format

func (f *TextFormatter) Format(entry *Entry) ([]byte, error)

Subdirectories