check.py

    def check(self, request):                                                   
        """Nagios health check"""                                               
        start = {}                                                              
                                                                                
        def nagios_start(status, headers, exc_info=None):                       
            # save status for inspection                                        
            start['status'] = status                                            
            start['headers'] = headers                                          
                                                                                  
        response = self.app(request.environ, nagios_start)                      
        if start['status'].startswith('404'):                                   
            # app does not provide /_status/nagios endpoint                     
            return self._ok                                                     
        else:                                                                   
            # return app's response                                             
            return Response(response,                                           
                            status=start['status'],                             
                            headers=start['headers'])