resp.is_locally_generated

BOOL, read-only.

Available indeliverlog

Whether request handling went through vcl_error.

Request handling will go through vcl_error and a response will be generated locally when the VCL executes the error action or when Varnish encounters a problem while handling the request, such as a communication failure with the backend. This VCL variable allows you to distinguish locally generated error responses from error responses received from upstream (from the origin or from a shield pop).

All synthetic responses are generated in vcl_error, not only error responses. If you use vcl_error to generate synthetic responses in non-error cases, you might need to check resp.status in combination with resp.is_locally_generated to determine that a response is a locally generated error response.