photoplaces/backend/internal/log/log.go

package log

import (
	"context"
	"log/slog"
	"os"
	"runtime"
)

type ctxKey string

const loggerKey ctxKey = "logger"

var defaultLogger *slog.Logger

func Init(env string) *slog.Logger {
	var handler slog.Handler

	if env == "production" {
		handler = slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{
			Level:     slog.LevelInfo,
			AddSource: true,
			ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
				if a.Key == slog.TimeKey {
					return slog.Attr{Key: "timestamp", Value: a.Value}
				}
				if a.Key == slog.LevelKey {
					return slog.Attr{Key: "level", Value: a.Value}
				}
				if a.Key == slog.MessageKey {
					return slog.Attr{Key: "message", Value: a.Value}
				}
				return a
			},
		})
	} else {
		handler = slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{
			Level:     slog.LevelDebug,
			AddSource: true,
		})
	}

	defaultLogger = slog.New(handler)
	slog.SetDefault(defaultLogger)
	return defaultLogger
}

func Default() *slog.Logger {
	if defaultLogger == nil {
		return slog.Default()
	}
	return defaultLogger
}

func FromContext(ctx context.Context) *slog.Logger {
	if logger, ok := ctx.Value(loggerKey).(*slog.Logger); ok {
		return logger
	}
	return Default()
}

func WithContext(ctx context.Context, logger *slog.Logger) context.Context {
	return context.WithValue(ctx, loggerKey, logger)
}

func WithRequestID(ctx context.Context, requestID string) *slog.Logger {
	return FromContext(ctx).With("request_id", requestID)
}

func WithUserID(ctx context.Context, userID string) *slog.Logger {
	return FromContext(ctx).With("user_id", userID)
}

func WithError(err error) slog.Attr {
	return slog.String("error", err.Error())
}

func WithFields(fields map[string]any) []slog.Attr {
	attrs := make([]slog.Attr, 0, len(fields))
	for k, v := range fields {
		attrs = append(attrs, slog.Any(k, v))
	}
	return attrs
}

func LogError(ctx context.Context, msg string, err error, args ...any) {
	logger := FromContext(ctx)
	allArgs := append([]any{"error", err}, args...)
	logger.ErrorContext(ctx, msg, allArgs...)
}

func LogWarn(ctx context.Context, msg string, args ...any) {
	FromContext(ctx).WarnContext(ctx, msg, args...)
}

func LogInfo(ctx context.Context, msg string, args ...any) {
	FromContext(ctx).InfoContext(ctx, msg, args...)
}

func LogDebug(ctx context.Context, msg string, args ...any) {
	FromContext(ctx).DebugContext(ctx, msg, args...)
}

func callerInfo(skip int) slog.Attr {
	_, file, line, ok := runtime.Caller(skip + 1)
	if !ok {
		return slog.String("caller", "unknown")
	}
	return slog.String("caller", file+":"+string(rune(line)))
}