wip refactoring: better logging and error systems

internal/app/api/pkg/middleware/cleanup.go

@@ -0,0 +1,38 @@
+package middleware
+
+import (
+	"github.com/labstack/echo/v4"
+	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/context"
+	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/resource"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/standarderror"
+)
+
+// Cleanup helps removing a resource at the end of a request.
+func Cleanup() echo.MiddlewareFunc {
+	return func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(c echo.Context) error {
+			const op = "middleware.Cleanup"
+			err := next(c)
+			ctx := context.MustCastFromEchoContext(c)
+			r := ctx.Resource()
+			if r == nil {
+				return err
+			}
+			// if a webhook URL has been given,
+			// do not remove the resource here because
+			// we don't know if the result file has been
+			// generated or sent.
+			if r.Has(resource.WebhookURLFormField) {
+				return err
+			}
+			// a resource is associated with our custom context.
+			if resourceErr := r.Close(); resourceErr != nil {
+				ctx.StandardLogger().ErrorOp(op, &standarderror.Error{
+					Op:  op,
+					Err: resourceErr,
+				})
+			}
+			return err
+		}
+	}
+}