log

Documentation

Index

• Constants
• func LevelName(level Level) string
• func NewTextHandler(options *Options) slog.Handler
• func WithHandler(handler slog.Handler) options.Option[Options]
• func WithLevel(level Level) options.Option[Options]
• func WithName(name string) options.Option[Options]
• func WithOutput(output io.Writer) options.Option[Options]
• func WithTimeFormat(timeFormat string) options.Option[Options]
• type Level
  • func LevelFromString(level string) (Level, error)
• type Logger
  • func NewLogger(opts ...options.Option[Options]) Logger
• type Options

Constants

const (
	// LevelTrace is the log level for trace messages.
	LevelTrace = slog.Level(-8)

	// LevelDebug is the log level for debug messages.
	LevelDebug = slog.LevelDebug

	// LevelInfo is the log level for info messages.
	LevelInfo = slog.LevelInfo

	// LevelWarning is the log level for warning messages.
	LevelWarning = slog.LevelWarn

	// LevelError is the log level for error messages.
	LevelError = slog.LevelError

	// LevelFatal is the log level for fatal messages.
	LevelFatal = slog.Level(12)

	// LevelPanic is the log level for panic messages.
	LevelPanic = slog.Level(16)
)

Functions

func LevelName

func LevelName(level Level) string

LevelName returns the name of the given log level.

func NewTextHandler

func NewTextHandler(options *Options) slog.Handler

NewTextHandler creates a new handler that writes human-readable log records to the given output.

func WithHandler

func WithHandler(handler slog.Handler) options.Option[Options]

WithHandler is an option to set the handler of a Logger.

func WithLevel

func WithLevel(level Level) options.Option[Options]

WithLevel is an option to set the log level of a Logger.

func WithName

func WithName(name string) options.Option[Options]

WithName is an option to set the name of a Logger.

func WithOutput

func WithOutput(output io.Writer) options.Option[Options]

WithOutput is an option to set the output of a Logger.

func WithTimeFormat

func WithTimeFormat(timeFormat string) options.Option[Options]

WithTimeFormat is an option to set the time format of a Logger.

Types

type Level

type Level = slog.Level

Level is the type of log levels.

func LevelFromString

func LevelFromString(level string) (Level, error)

LevelFromString returns the log level for the given string.

type Logger

type Logger interface {
	// LogName returns the name of the logger instance.
	LogName() string

	// LogPath returns the full path of the logger that is formed by a combination of the names of its ancestors and
	// its own name.
	LogPath() string

	// LogLevel returns the current log level of the logger.
	LogLevel() Level

	// SetLogLevel sets the log level of the logger.
	SetLogLevel(level Level)

	// OnLogLevelActive registers a callback that is triggered when the given log level is activated. The shutdown
	// function that is returned by the callback is automatically called when the log level is deactivated.
	OnLogLevelActive(logLevel Level, setup func() (shutdown func())) (unsubscribe func())

	// LogTrace emits a log message with the TRACE level.
	LogTrace(msg string, args ...any)

	// LogTracef emits a formatted log message with the TRACE level.
	LogTracef(fmtString string, args ...any)

	// LogTraceAttrs emits a log message with the TRACE level and the given attributes.
	LogTraceAttrs(msg string, args ...slog.Attr)

	// LogDebug emits a log message with the DEBUG level.
	LogDebug(msg string, args ...any)

	// LogDebugf emits a formatted log message with the DEBUG level.
	LogDebugf(fmtString string, args ...any)

	// LogDebugAttrs emits a log message with the DEBUG level and the given attributes.
	LogDebugAttrs(msg string, args ...slog.Attr)

	// LogInfo emits a log message with the INFO level.
	LogInfo(msg string, args ...any)

	// LogInfof emits a formatted log message with the INFO level.
	LogInfof(fmtString string, args ...any)

	// LogInfoAttrs emits a log message with the INFO level and the given attributes.
	LogInfoAttrs(msg string, args ...slog.Attr)

	// LogWarn emits a log message with the WARN level.
	LogWarn(msg string, args ...any)

	// LogWarnf emits a formatted log message with the WARN level.
	LogWarnf(fmtString string, args ...any)

	// LogWarnAttrs emits a log message with the WARN level and the given attributes.
	LogWarnAttrs(msg string, args ...slog.Attr)

	// LogError emits a log message with the ERROR level.
	LogError(msg string, args ...any)

	// LogErrorf emits a formatted log message with the ERROR level.
	LogErrorf(fmtString string, args ...any)

	// LogErrorAttrs emits a log message with the ERROR level and the given attributes.
	LogErrorAttrs(msg string, args ...slog.Attr)

	// LogFatal emits a log message with the FATAL level, then calls os.Exit(1).
	LogFatal(msg string, args ...any)

	// LogFatalf emits a formatted log message with the FATAL level, then calls os.Exit(1).
	LogFatalf(fmtString string, args ...any)

	// LogFatalAttrs emits a log message with the FATAL level and the given attributes, then calls os.Exit(1).
	LogFatalAttrs(fmtString string, args ...slog.Attr)

	// LogPanic emits a log message with the PANIC level, then panics.
	LogPanic(msg string, args ...any)

	// LogPanicf emits a formatted log message with the PANIC level, then panics.
	LogPanicf(fmtString string, args ...any)

	// LogPanicAttrs emits a log message with the PANIC level and the given attributes, then panics.
	LogPanicAttrs(fmtString string, args ...slog.Attr)

	// Log emits a log message with the given level.
	Log(msg string, level Level, args ...any)

	// Logf emits a formatted log message with the given level.
	Logf(fmtString string, level Level, args ...any)

	// LogAttrs emits a log message with the given level and attributes.
	LogAttrs(msg string, level Level, args ...slog.Attr)

	// NewChildLogger creates a new child logger with the given name. If enumerateChildren is true, the child logger
	// will extend the name with the number of existing child loggers with the same name.
	NewChildLogger(name string, enumerateChildren ...bool) Logger

	// ParentLogger returns the parent of this Logger (or nil if it is the root).
	ParentLogger() Logger

	// Shutdown shuts down the logger by either unsubscribing from its parent logger or shutting down the root logger.
	//
	// Note: It is important to call this method whenever we remove all references to a child logger, otherwise the
	// logger will not be garbage collected until the root logger is garbage collected.
	Shutdown()
}

Logger is a reactive logger that can be used to log messages with different log levels.

var EmptyLogger Logger = (*logger)(nil)

EmptyLogger is a logger that does not log anything.

func NewLogger

func NewLogger(opts ...options.Option[Options]) Logger

NewLogger creates a new logger with the given options. If no options are provided, the logger uses the info level and writes to stdout with rfc3339 time format.

type Options

type Options struct {
	// Name is the name of the logger.
	Name string

	// Level is the log level of the logger.
	Level Level

	// TimeFormat is the time format of the logger.
	TimeFormat string

	// Output is the output of the logger.
	Output io.Writer

	// Handler is the handler of the logger.
	Handler slog.Handler
}

Options contains the configuration options for a Logger.