Set up am implicit tween to log exception information that is generated by your Pyramid application. The logging data will be sent to the Python logger named exc_logger.
This tween configured to be placed ‘below’ the exception view tween. It will log all exceptions (even those eventually caught by a Pyramid exception view) except ‘http exceptions’ (any exception that derives from pyramid.httpexceptions.WSGIHTTPException such as HTTPFound). You can instruct pyramid_exclog to ignore custom exception types by using the excview.ignore configuration setting.