inventory-plus-plus/logging/logger.go

package logging

import (
	"context"
	"fmt"
	"log/slog"
	"runtime"
	"time"
)

// Logger creates a *slog.Logger wrap with a few more methods wrapped on top.
// It recreates a number of methods to allow replacing a *slog.Logger functionally.
// It also implements a number of methods to support formatted messages and
// tracing.
type Logger struct {
	*slog.Logger
}

func New(h slog.Handler) *Logger {
	return &Logger{
		Logger: slog.New(h),
	}
}

func From(l *slog.Logger) *Logger {
	return &Logger{
		Logger: l,
	}
}

func (l *Logger) With(args ...any) *Logger {
	return From(l.Logger.With(args...))
}

func (l *Logger) WithGroup(name string) *Logger {
	return From(l.Logger.WithGroup(name))
}

func (l *Logger) Debugf(format string, args ...any) {
	l.logContextf(context.Background(), slog.LevelDebug, format, args...)
}

func (l *Logger) DebugContextf(ctx context.Context, format string, args ...any) {
	l.logContextf(ctx, slog.LevelDebug, format, args...)
}

func (l *Logger) DebugDeferf(format string, args ...any) func(func() (string, []any)) {
	return l.logContextDeferf(context.Background(), slog.LevelDebug, format, args...)
}

func (l *Logger) DebugContextDeferf(ctx context.Context, format string, args ...any) func(func() (string, []any)) {
	return l.logContextDeferf(ctx, slog.LevelDebug, format, args...)
}

func (l *Logger) DebugCallf(method string) func() {
	return l.logContextCallf(context.Background(), slog.LevelDebug, method)
}

func (l *Logger) DebugContextCallf(ctx context.Context, method string) func() {
	return l.logContextCallf(ctx, slog.LevelDebug, method)
}

func (l *Logger) Errorf(format string, args ...any) {
	l.logContextf(context.Background(), slog.LevelError, format, args...)
}

func (l *Logger) ErrorContextf(ctx context.Context, format string, args ...any) {
	l.logContextf(ctx, slog.LevelError, format, args...)
}

func (l *Logger) ErrorDeferf(format string, args ...any) func(func() (string, []any)) {
	return l.logContextDeferf(context.Background(), slog.LevelError, format, args...)
}

func (l *Logger) ErrorContextDeferf(ctx context.Context, format string, args ...any) func(func() (string, []any)) {
	return l.logContextDeferf(ctx, slog.LevelError, format, args...)
}

func (l *Logger) ErrorCallf(method string) func() {
	return l.logContextCallf(context.Background(), slog.LevelError, method)
}

func (l *Logger) ErrorContextCallf(ctx context.Context, method string) func() {
	return l.logContextCallf(ctx, slog.LevelError, method)
}

func (l *Logger) Infof(format string, args ...any) {
	l.logContextf(context.Background(), slog.LevelInfo, format, args...)
}

func (l *Logger) InfoContextf(ctx context.Context, format string, args ...any) {
	l.logContextf(ctx, slog.LevelInfo, format, args...)
}

func (l *Logger) InfoDeferf(format string, args ...any) func(func() (string, []any)) {
	return l.logContextDeferf(context.Background(), slog.LevelInfo, format, args...)
}

func (l *Logger) InfoContextDeferf(ctx context.Context, format string, args ...any) func(func() (string, []any)) {
	return l.logContextDeferf(ctx, slog.LevelInfo, format, args...)
}

func (l *Logger) InfoCallf(method string) func() {
	return l.logContextCallf(context.Background(), slog.LevelInfo, method)
}

func (l *Logger) InfoContextCallf(ctx context.Context, method string) func() {
	return l.logContextCallf(ctx, slog.LevelInfo, method)
}

func (l *Logger) Warnf(format string, args ...any) {
	l.logContextf(context.Background(), slog.LevelWarn, format, args...)
}

func (l *Logger) WarnContextf(ctx context.Context, format string, args ...any) {
	l.logContextf(ctx, slog.LevelWarn, format, args...)
}

func (l *Logger) WarnDeferf(format string, args ...any) func(func() (string, []any)) {
	return l.logContextDeferf(context.Background(), slog.LevelWarn, format, args...)
}

func (l *Logger) WarnContextDeferf(ctx context.Context, format string, args ...any) func(func() (string, []any)) {
	return l.logContextDeferf(ctx, slog.LevelWarn, format, args...)
}

func (l *Logger) WarnCallf(method string) func() {
	return l.logContextCallf(context.Background(), slog.LevelWarn, method)
}

func (l *Logger) WarnContextCallf(ctx context.Context, method string) func() {
	return l.logContextCallf(ctx, slog.LevelWarn, method)
}

func (l *Logger) logContextf(ctx context.Context, lvl slog.Level, format string, args ...any) {
	if !l.Enabled(ctx, slog.LevelInfo) {
		return
	}

	var pcs [1]uintptr
	runtime.Callers(3, pcs[:]) // skip [Callers, Infof]

	_ = l.Handler().Handle(
		ctx,
		slog.NewRecord(time.Now(), lvl, fmt.Sprintf(format, args...), pcs[0]),
	)
}

func (l *Logger) logContextCallf(ctx context.Context, lvl slog.Level, method string) func() {
	fn := l.With("method", method).logContextDeferf(ctx, lvl, "%s called", method)
	return func() {
		fn(func() (string, []any) {
			return "%s returned", []any{method}
		})
	}
}

func (l *Logger) logContextDeferf(ctx context.Context, lvl slog.Level, format string, args ...any) func(func() (msg string, args []any)) {
	if !l.Enabled(ctx, slog.LevelInfo) {
		return func(func() (string, []any)) {
		}
	}

	var pcs [1]uintptr
	runtime.Callers(3, pcs[:]) // skip [Callers, Infof]
	pc := pcs[0]

	_ = l.Handler().Handle(ctx, slog.NewRecord(time.Now(), lvl, fmt.Sprintf(format, args...), pc))
	return func(deferred func() (newFormat string, moreArgs []any)) {
		if !l.Enabled(ctx, slog.LevelInfo) {
			return
		}

		if deferred != nil {
			format, args = deferred()
		}

		_ = l.Handler().Handle(ctx, slog.NewRecord(time.Now(), lvl, fmt.Sprintf(format, args...), pc))
	}
}