+ # call this function repeatedly for streaming measurements\r
+ def get_rate(self, vnf_name, vnf_interface=None, direction='tx', metric='packets'):\r
+\r
+ key = self.metric_key\r
+\r
+ ret = self.REST_cmd('stats/port', self.switch_dpid)\r
+ port_stat_dict = ast.literal_eval(ret)\r
+ for port_stat in port_stat_dict[str(self.switch_dpid)]:\r
+ if port_stat['port_no'] == self.mon_port:\r
+ port_uptime = port_stat['duration_sec'] + port_stat['duration_nsec'] * 10 ** (-9)\r
+ this_measurement = port_stat[key]\r
+\r
+ if self.previous_monitor_time <= 0 or self.previous_monitor_time >= port_uptime:\r
+ self.previous_measurement = port_stat[key]\r
+ self.previous_monitor_time = port_uptime\r
+ # do first measurement\r
+ time.sleep(1)\r
+ byte_rate = self.get_rate(vnf_name, vnf_interface, direction, metric)\r
+ return byte_rate\r
+ else:\r
+ time_delta = (port_uptime - self.previous_monitor_time)\r
+ byte_rate = (this_measurement - self.previous_measurement) / float(time_delta)\r
+ #logging.info('uptime:{2} delta:{0} rate:{1}'.format(time_delta,byte_rate,port_uptime))\r
+\r
+ self.previous_measurement = this_measurement\r
+ self.previous_monitor_time = port_uptime\r
+ return byte_rate\r
+\r
+ return ret\r