humane

Documentation

Overview

Package humane provides a log/slog.Handler for a human-friendly version of logfmt. The idea for this format comes from Brandur Leach in his original post about logfmt. (In particular, this is the inspiration.)

Examples:

1. Get a slog logger using humane's handler with default options:

logger := slog.New(humane.NewHandler(os.Stdout, nil))
logger.Info("Message", "foo", "bar", "bizz", "buzz")

2. Get a slog logger using humane's handler with customized options:

func trimSource(_ []string, a slog.Attr) slog.Attr {
	if a.Key == slog.SourceKey {
		return slog.String(
			slog.SourceKey,
			filepath.Base(a.Value.String()),
		)
	}
	return a
}

func main() {
	opts := &humane.Options{
		Level:       slog.LevelError,
		ReplaceAttr: trimSource,
		TimeFormat:  time.Kitchen,
		AddSource:   true,
	}
	logger := slog.New(humane.NewHandler(os.Stderr, opts))
	// ... later
	logger.Error("Message", "error", err, "response", respStatus)
}

Index

• func NewHandler(w io.Writer, opts *Options) slog.Handler
• type Options

Functions

func NewHandler

func NewHandler(w io.Writer, opts *Options) slog.Handler

NewHandler returns a log/slog.Handler using the receiver's options. Default options are used if opts is nil.

Types

type Options

type Options struct {
	Level       slog.Leveler
	ReplaceAttr func(groups []string, a slog.Attr) slog.Attr
	TimeFormat  string
	AddSource   bool
}

Options are options for Humane's log/slog.Handler.

Level reports the minimum level to log. Humane uses log/slog.LevelInfo as its default level. In order to set a different level, use one of the built-in choices for log/slog.Level or implement a log/slog.Leveler.

ReplaceAttr is a user-defined function that receives each non-group Attr before it is logged. By default, ReplaceAttr is nil, and no changes are made to Attrs. Note: Humane's handler does not apply ReplaceAttr to the level or message Attrs because the handler already formats these items in a specific way. However, Humane does apply ReplaceAttr to the time Attr (unless it's zero) and to the source Attr if AddSource is true.

TimeFormat defaults to "2006-01-02T03:04.05 MST". Set a format option to customize the presentation of the time. (See time.Time.Format for details about the format string.)

AddSource defaults to false. If AddSource is true, the handler adds to each log event an Attr with log/slog.SourceKey as the key and "file:line" as the value.