middleware.go

package main

import (
	"context"
	"log/slog"
	"net/http"
	"time"

	"github.com/google/uuid"
)

type contextKey string

const requestIDKey contextKey = "requestID"

func RequestIDMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		requestID := r.Header.Get("X-Request-ID")
		if requestID == "" {
			requestID = uuid.New().String()
		}

		ctx := context.WithValue(r.Context(), requestIDKey, requestID)

		w.Header().Set("X-Request-ID", requestID)

		next.ServeHTTP(w, r.WithContext(ctx))
	})
}

func GetRequestID(ctx context.Context) string {
	if id, ok := ctx.Value(requestIDKey).(string); ok {
		return id
	}
	return ""
}

type responseWriter struct {
	http.ResponseWriter
	statusCode int
}

func newResponseWriter(w http.ResponseWriter) *responseWriter {
	return &responseWriter{
		ResponseWriter: w,
		statusCode:     http.StatusOK, // по умолчанию 200 если WriteHeader не вызвали
	}
}

func (rw *responseWriter) WriteHeader(statusCode int) {
	rw.statusCode = statusCode
	rw.ResponseWriter.WriteHeader(statusCode)
}

func LoggerMiddleware(logger *slog.Logger) func(http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			start := time.Now()

			wrapped := newResponseWriter(w)

			next.ServeHTTP(wrapped, r)

			logger.Info("request",
				slog.String("method", r.Method),
				slog.String("path", r.URL.Path),
				slog.Int("status", wrapped.statusCode),
				slog.Duration("latency", time.Since(start)),
				slog.String("request_id", GetRequestID(r.Context())),
				slog.String("remote_addr", r.RemoteAddr),
			)
		})
	}
}

func RecoverMiddleware(logger *slog.Logger) func(http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			defer func() {
				if err := recover(); err != nil {
					logger.Error("panic recovered",
						slog.Any("error", err),
						slog.String("request_id", GetRequestID(r.Context())),
						slog.String("path", r.URL.Path),
					)

					http.Error(w, "internal server error", http.StatusInternalServerError)
				}
			}()

			next.ServeHTTP(w, r)
		})
	}
}