feat: global error handler with template rendering

internal/proxy/director/director.go

@@ -22,6 +22,8 @@ type Director struct {
 
 	proxyCache cache.Cache[string, []*store.Proxy]
 	layerCache cache.Cache[string, []*store.Layer]
+
+	handleError HandleErrorFunc
 }
 
 func (d *Director) rewriteRequest(r *http.Request) (*http.Request, error) {
@@ -33,7 +35,6 @@ func (d *Director) rewriteRequest(r *http.Request) (*http.Request, error) {
 	}
 
 	url := getRequestURL(r)
-
 	ctx = withOriginalURL(ctx, url)
 	ctx = logger.With(ctx, logger.F("url", url.String()))
 
@@ -169,6 +170,7 @@ func (d *Director) getLayers(ctx context.Context, proxyName store.ProxyName) ([]
 func (d *Director) RequestTransformer() proxy.RequestTransformer {
 	return func(r *http.Request) {
 		ctx := r.Context()
+
 		layers, err := ctxLayers(ctx)
 		if err != nil {
 			if errors.Is(err, errContextKeyNotFound) {
@@ -225,15 +227,16 @@ func (d *Director) ResponseTransformer() proxy.ResponseTransformer {
 func (d *Director) Middleware() proxy.Middleware {
 	return func(next http.Handler) http.Handler {
 		fn := func(w http.ResponseWriter, r *http.Request) {
+			ctx := withHandleError(r.Context(), d.handleError)
+			r = r.WithContext(ctx)
+
 			r, err := d.rewriteRequest(r)
 			if err != nil {
-				logger.Error(r.Context(), "could not rewrite request", logger.CapturedE(errors.WithStack(err)))
-				http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
-
+				HandleError(ctx, w, r, http.StatusInternalServerError, errors.Wrap(err, "could not rewrite request"))
 				return
 			}
 
-			ctx := r.Context()
+			ctx = r.Context()
 
 			layers, err := ctxLayers(ctx)
 			if err != nil {
@@ -241,9 +244,7 @@ func (d *Director) Middleware() proxy.Middleware {
 					return
 				}
 
-				logger.Error(ctx, "could not retrieve proxy and layers from context", logger.CapturedE(errors.WithStack(err)))
-				http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
-
+				HandleError(ctx, w, r, http.StatusInternalServerError, errors.Wrap(err, "could not retrieve proxy and layers from context"))
 				return
 			}
 
@@ -278,5 +279,6 @@ func New(proxyRepository store.ProxyRepository, layerRepository store.LayerRepos
 		layerRegistry:   registry,
 		proxyCache:      opts.ProxyCache,
 		layerCache:      opts.LayerCache,
+		handleError:     opts.HandleError,
 	}
 }