levelwriter.go

package golog

import (
	"context"
	"fmt"
	"log"
)

// LevelWriter writes unstructured messages to a Logger with a fixed Level.
// It can be used as a shim/wrapper for third party packages
// that need a standard log.Logger, an io.Writer,
// or an an interface implementation with a Printf method.
type LevelWriter struct {
	logger *Logger
	level  Level
}

// Write implements io.Writer
func (w *LevelWriter) Write(data []byte) (int, error) {
	w.WriteMessage(context.Background(), string(data))
	return len(data), nil
}

// WriteMessage writes a string message.
func (w *LevelWriter) WriteMessage(ctx context.Context, msg string) {
	if w.logger == nil {
		return
	}
	// Remove newline at end
	if last := len(msg) - 1; last >= 0 && msg[last] == '\n' {
		msg = msg[:last]
	}
	w.logger.NewMessage(ctx, w.level, msg).Log()
}

func (w *LevelWriter) Print(v ...any) {
	w.WriteMessage(context.Background(), fmt.Sprint(v...))
}

func (w *LevelWriter) Println(v ...any) {
	w.WriteMessage(context.Background(), fmt.Sprintln(v...))
}

func (w *LevelWriter) Printf(format string, v ...any) {
	w.WriteMessage(context.Background(), fmt.Sprintf(format, v...))
}

// Func returns a function with the log.Printf call signature.
func (w *LevelWriter) Func() func(format string, v ...any) {
	return func(format string, v ...any) {
		w.Printf(format, v...)
	}
}

// StdLogger returns a new log.Logger that writes to the LevelWriter.
// See https://golang.org/pkg/log/
func (w *LevelWriter) StdLogger() *log.Logger {
	return log.New(w, "", 0)
}