logger

README

logger

A configurable structure leveled logger stored in context with an adapter interface for logger libraries allows not to depend on any of them directly.

Documentation

Index

• Constants
• Variables
• func ContextWithLogger(ctx context.Context, l Logger) context.Context
• func Debug(ctx context.Context, msg string)
• func Error(ctx context.Context, msg string)
• func Fatal(ctx context.Context, msg string)
• func Info(ctx context.Context, msg string)
• func Warn(ctx context.Context, msg string)
• type Fields
• type Level
  • func ParseLevel(lvl string) (Level, error)
• type Logger
  • func FromContext(ctx context.Context) Logger
  • func Init(ctx context.Context, p Params) Logger
  • func WithError(ctx context.Context, err error) Logger
  • func WithField(ctx context.Context, key string, value interface{}) Logger
  • func WithFields(ctx context.Context, fields map[string]interface{}) Logger
• type Params

Constants

const (
	// LevelDebug is a debug level.
	LevelDebug = slog.LevelDebug
	// LevelInfo is an info level.
	LevelInfo = slog.LevelInfo
	// LevelWarn is a warn level.
	LevelWarn = slog.LevelWarn
	// LevelError is an error level.
	LevelError = slog.LevelError
	// LevelFatal is a fatal level.
	LevelFatal = slog.Level(12)
)

Variables

var AllLevels = []Level{
	LevelDebug,
	LevelInfo,
	LevelWarn,
	LevelError,
	LevelFatal,
}

AllLevels is a slice of all levels.

Functions

func ContextWithLogger

func ContextWithLogger(ctx context.Context, l Logger) context.Context

ContextWithLogger adds Logger to context and returns new context.

func Debug

func Debug(ctx context.Context, msg string)

Debug prints debug-level log message. Usually very verbose and shown only when debug level is enabled.

func Error

func Error(ctx context.Context, msg string)

Error prints error-level log message.

func Fatal

func Fatal(ctx context.Context, msg string)

Fatal prints fatal-level log message and exit the program with code 1.

func Info

func Info(ctx context.Context, msg string)

Info prints info-level log message.

func Warn

func Warn(ctx context.Context, msg string)

Warn prints warn-level log message.

Types

type Fields

type Fields map[string]interface{}

Fields type, used to pass to `WithFields`.

type Level

type Level = slog.Level

Level type.

func ParseLevel

func ParseLevel(lvl string) (Level, error)

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

type Logger

type Logger interface {
	Debug(msg string)
	Info(msg string)
	Warn(msg string)
	Error(msg string)
	Fatal(msg string)

	WithError(err error) Logger
	WithField(key string, value interface{}) Logger
	WithFields(fields Fields) Logger
}

Logger serves as an adapter interface for logger libraries so that we not depend on any of them directly.

func FromContext

func FromContext(ctx context.Context) Logger

FromContext extracts Logger from context. If no instance found - returns Logger from default logInstance.

func Init

func Init(ctx context.Context, p Params) Logger

Init initiates logger and add format options. Should be called only once, on start of app.

func WithError

func WithError(ctx context.Context, err error) Logger

WithError adds an error as single field to the Logger Entry.

func WithField

func WithField(ctx context.Context, key string, value interface{}) Logger

WithField adds s single field to the Logger Entry.

func WithFields

func WithFields(ctx context.Context, fields map[string]interface{}) Logger

WithFields adds fields key-value to the Logger Entry.

type Params

type Params struct {
	// Writer is a writer to write logs to. By default, it's os.Stderr.
	Writer io.WriteCloser
	// Level is one of "debug", "info", "warn", "error", "fatal".
	Level string
	// Format is one of "json" or "text".
	Format string
	// WithSource enables source code info in logs.
	WithSource bool
}

Params holds logger specific params.