Getting flow infos from switch and copy the info in csv file (Ryu controller) - sdn

Question

Hope you help me, I want to get flow info from switch and that by sending a request every 10s and the switch reply with the info but I get the following error when the controller receive the reply by using a flow request reply handler The error is occuring because of flow matching 'eth_type'
CollectTrainingStatsApp: Exception occurred during handler processing. Backtrace from offending handler [_flow_stats_reply_handler] servicing event [EventOFPFlowStatsReply] follows.
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/ryu/base/app_manager.py", line 290, in _event_loop
handler(ev)
File "/home/guenfaf/Documents/Training ryu/data_to_csv/data_to_csv.py", line 59, in _flow_stats_reply_handler
for stat in sorted([flow for flow in body if (flow.priority == 1) ], key=lambda flow:
File "/home/guenfaf/Documents/Training ryu/data_to_csv/data_to_csv.py", line 60, in <lambda>
(flow.match['eth_type'],flow.match['ipv4_src'],flow.match['ipv4_dst'],flow.match['ip_proto'])):
File "/usr/local/lib/python2.7/dist-packages/ryu/ofproto/ofproto_v1_3_parser.py", line 904, in __getitem__
return dict(self._fields2)[key]
KeyError: 'eth_type'
Here is my code :
from ryu.app import simple_switch_13
from ryu.controller import ofp_event
from ryu.controller.handler import MAIN_DISPATCHER, DEAD_DISPATCHER
from ryu.controller.handler import set_ev_cls
from ryu.lib import hub
from time import time
# class CollectTrainingStatsApp(simple_switch_13.SimpleSwitch13):
class CollectTrainingStatsApp(simple_switch_13.SimpleSwitch13):
def __init__(self, *args, **kwargs):
super(CollectTrainingStatsApp, self).__init__(*args, **kwargs)
self.datapaths = {}
self.monitor_thread = hub.spawn(self.monitor)
file0 = open("FlowStatsfile.csv","w")
file0.write('datapath_id,flow_id,ip_src,tp_src,ip_dst,tp_dst,ip_proto,flow_duration_sec,flow_duration_nsec,idle_timeout,hard_timeout,flags,packet_count,byte_count,packet_count_per_second,packet_count_per_nsecond,byte_count_per_second,byte_count_per_nsecond,label\n')
file0.close()
#Asynchronous message
#set_ev_cls(ofp_event.EventOFPStateChange,[MAIN_DISPATCHER, DEAD_DISPATCHER])
def state_change_handler(self, ev):
datapath = ev.datapath
if ev.state == MAIN_DISPATCHER:
if datapath.id not in self.datapaths:
self.logger.debug('register datapath: %016x', datapath.id)
self.datapaths[datapath.id] = datapath
elif ev.state == DEAD_DISPATCHER:
if datapath.id in self.datapaths:
self.logger.debug('unregister datapath: %016x', datapath.id)
del self.datapaths[datapath.id]
def monitor(self):
while True:
for dp in self.datapaths.values():
self.request_stats(dp)
hub.sleep(10)
def request_stats(self, datapath):
self.logger.debug('send stats request: %016x', datapath.id)
parser = datapath.ofproto_parser
req = parser.OFPFlowStatsRequest(datapath)
datapath.send_msg(req)
#set_ev_cls(ofp_event.EventOFPFlowStatsReply, MAIN_DISPATCHER)
def _flow_stats_reply_handler(self, ev):
#timestamp = time.time()
tp_src = 0
tp_dst = 0
file0 = open("FlowStatsfile.csv","a+")
body = ev.msg.body
for stat in sorted([flow for flow in body if (flow.priority == 1) ], key=lambda flow:
(flow.match['eth_type'],flow.match['ipv4_src'],flow.match['ipv4_dst'],flow.match['ip_proto'])):
ip_src = stat.match['ipv4_src']
ip_dst = stat.match['ipv4_dst']
ip_proto = stat.match['ip_proto']
if stat.match['ip_proto'] == 1:
icmp_code = stat.match['icmpv4_code']
icmp_type = stat.match['icmpv4_type']
elif stat.match['ip_proto'] == 6:
tp_src = stat.match['tcp_src']
tp_dst = stat.match['tcp_dst']
elif stat.match['ip_proto'] == 17:
tp_src = stat.match['udp_src']
tp_dst = stat.match['udp_dst']
flow_id = str(ip_src) + str(tp_src) + str(ip_dst) + str(tp_dst) + str(ip_proto)
try:
packet_count_per_second = stat.packet_count/stat.duration_sec
packet_count_per_nsecond = stat.packet_count/stat.duration_nsec
except:
packet_count_per_second = 0
packet_count_per_nsecond = 0
try:
byte_count_per_second = stat.byte_count/stat.duration_sec
byte_count_per_nsecond = stat.byte_count/stat.duration_nsec
except:
byte_count_per_second = 0
byte_count_per_nsecond = 0
file0.write("{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{}\n"
.format(ev.msg.datapath.id, flow_id, ip_src, tp_src,ip_dst, tp_dst,
stat.match['ip_proto'],
stat.duration_sec, stat.duration_nsec,
stat.idle_timeout, stat.hard_timeout,
stat.flags, stat.packet_count,stat.byte_count,
packet_count_per_second,packet_count_per_nsecond,
byte_count_per_second,byte_count_per_nsecond,0))
file0.close()