slog

Documentation

Overview

The slog package provides utilities for log/slog use cases.

Index

• Variables
• func NewSlogLogger(writer io.Writer, handler Handler, leveler slog.Leveler) *slog.Logger
• type Handler
  • func (h Handler) MarshalText() ([]byte, error)
  • func (h Handler) String() string
  • func (h *Handler) UnmarshalText(b []byte) error

Examples

• Handler.MarshalText
• Handler.String
• Handler.UnmarshalText
• NewSlogLogger
• NewSlogLogger (SetDefault)

Variables

var (
	// ErrUnknownHandlerName is returned when an unknown slog handler name is used.
	ErrUnknownHandlerName = errors.New("unknown handler name")
)

Errors used by the slog package.

Functions

func NewSlogLogger

func NewSlogLogger(writer io.Writer, handler Handler, leveler slog.Leveler) *slog.Logger

NewSlogLogger creates an slog Logger that outputs to writer, using the specified log handler and the specified leveler implementation (for minimum logging level). This function also renames the built-in slog.TimeKey attribute to "ts" for shorter log lines.

Example

package main

import (
	"log/slog"
	"os"

	tkslog "github.com/hhromic/go-toolkit/slog"
)

func main() {
	h := tkslog.HandlerText
	l := slog.LevelDebug
	logger := tkslog.NewSlogLogger(os.Stdout, h, l)

	version := "1.2.3"
	logger.Info("application started", "version", version)
}

Example (SetDefault)

package main

import (
	"log/slog"
	"os"

	tkslog "github.com/hhromic/go-toolkit/slog"
)

func main() {
	h := tkslog.HandlerText
	l := slog.LevelDebug
	logger := tkslog.NewSlogLogger(os.Stdout, h, l)

	slog.SetDefault(logger)

	version := "1.2.3"
	slog.Info("application started", "version", version)
}

Types

type Handler

type Handler int

Handler represents a supported slog handler.

const (
	// HandlerText is an slog TextHandler which outputs logs in key=value format.
	HandlerText Handler = iota
	// HandlerJSON is an slog JSONHandler which outputs logs in standard JSON format.
	HandlerJSON
	// HandlerTint is an slog Handler which outputs colorized logs in key=value format.
	HandlerTint
	// HandlerAuto uses HandlerTint if the output writer is a terminal or HandlerText otherwise.
	HandlerAuto
)

Supported slog handlers.

func (Handler) MarshalText

func (h Handler) MarshalText() ([]byte, error)

MarshalText implements encoding.TextMarshaler by calling Handler.String.

Example

package main

import (
	"fmt"

	tkslog "github.com/hhromic/go-toolkit/slog"
)

func main() {
	h := tkslog.HandlerText

	b, err := h.MarshalText()
	if err != nil {
		panic(err)
	}

	fmt.Println(b)
}

Output:

[116 101 120 116]

func (Handler) String

func (h Handler) String() string

String returns a name for the slog handler.

Example

package main

import (
	"fmt"

	tkslog "github.com/hhromic/go-toolkit/slog"
)

func main() {
	h := tkslog.HandlerText
	fmt.Println(h.String())
}

Output:

text

func (*Handler) UnmarshalText

func (h *Handler) UnmarshalText(b []byte) error

UnmarshalText implements encoding.TextUnmarshaler. It accepts any slice of bytes produced by Handler.MarshalText.

Example

package main

import (
	"fmt"

	tkslog "github.com/hhromic/go-toolkit/slog"
)

func main() {
	b := []byte{116, 101, 120, 116}

	var h tkslog.Handler
	if err := h.UnmarshalText(b); err != nil {
		panic(err)
	}

	fmt.Println(h.String())
}

Output:

text