build.main.Main._is_flows_equal() - Code Metrics - Inspection of "Added flow persistence" - kytos/flow_manager - Measure and Improve Code Quality continuously with Scrutinizer

Passed

Pull Request — master (#90)

by Carlos

created 2020-11-12 14:56 UTC

build.main.Main._is_flows_equal() A

↳ Parent: build.main

Complexity

Conditions

Size

Total Lines	7
Code Lines	6

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	5
CRAP Score	2.0185

Importance

Changes

Metric	Value
cc	2
eloc	6
nop	3
dl	0
loc	7
rs	10
c	0
b	0
f	0
ccs	5
cts	6
cp	0.8333
crap	2.0185

"""kytos/flow_manager NApp installs, lists and deletes switch flows."""
from collections import OrderedDict

from flask import jsonify, request

from kytos.core import KytosEvent, KytosNApp, log, rest
from kytos.core.helpers import listen_to
from napps.kytos.flow_manager.storehouse import StoreHouse
from napps.kytos.of_core.flow import FlowFactory

from .exceptions import InvalidCommandError
from .settings import FLOWS_DICT_MAX_SIZE


class Main(KytosNApp):
    """Main class to be used by Kytos controller."""

    def setup(self):
        """Replace the 'init' method for the KytosApp subclass.

        The setup method is automatically called by the run method.
        Users shouldn't call this method directly.
        """
        log.debug("flow-manager starting")
        self._flow_mods_sent = OrderedDict()
        self._flow_mods_sent_max_size = FLOWS_DICT_MAX_SIZE

        # Format of stored data
        # {"flow_persistence":{
        #     "dpid_str":{
        #         "flow_list":[
        #             {"command":<add|delete>}
        #             "flow":{flow_dict},
        #         ]
        #     }
        # }}
        # client to load and save data in storehouse
        self.storehouse = StoreHouse(self.controller)
        self.stored_flows = {}
        self.resent_flows = set()

    def execute(self):
        """Run once on NApp 'start' or in a loop.

        The execute method is called by the run method of KytosNApp class.
        Users shouldn't call this method directly.
        """
        self._load_flows()

    def shutdown(self):
        """Shutdown routine of the NApp."""
        log.debug("flow-manager stopping")

    @listen_to('kytos/topology.port.created')
    def resend_stored_flows(self, event):
        """Resend stored Flows."""
        dpid = str(event.content['switch'])
        switch = self.controller.get_switch_by_dpid(dpid)
        # This can be a problem because this code is running a thread
        if dpid in self.resent_flows:
            log.info(f'Flow already resended to Switch {dpid}')
            return
        if dpid in self.stored_flows:
            flow_list = self.stored_flows[dpid]['flow_list']
            for flow in flow_list:
                command = flow['command']
                flows_dict = {"flows": [flow['flow']]}
                self._install_flows(command, flows_dict, [switch])
            self.resent_flows.add(dpid)
            log.info(f'Flows resent to Switch {dpid}')

    # pylint: disable=attribute-defined-outside-init
    def _load_flows(self):
        """Load stored flows."""
        try:
            data = self.storehouse.get_data()['flow_persistence']
            if 'id' in data:
                del data['id']
            self.stored_flows = data

        except KeyError as error:
            log.debug(f'There are no flows to load: {error}')
        else:
            log.info('Flows loaded.')

    @staticmethod
    def _generate_match_fields(flows):
        """Generate flow match fields."""
        match_fields = {}
        flow = flows.get('flow')
        print(flow)
        for field in flow:
            if 'priority' in field:
                match_fields['priority'] = flow['priority']
            if 'cookie' in field:
                match_fields['cookie'] = flow['cookie']
            if 'match' in field:
                for m_field, value in flow['match'].items():
                    match_fields[m_field] = value
        return match_fields

    def _is_flows_equal(self, flow_1, flow_2):
        """Check if two flows are equal."""
        flow_1_match_fields = self._generate_match_fields(flow_1)
        flow_2_match_fields = self._generate_match_fields(flow_2)
        if flow_1_match_fields == flow_2_match_fields:
            return True
        return False

    def _store_changed_flows(self, command, flow, switch):
        """Store changed flows.

        Args:
            command: Flow command to be installed
            flow: Flows to be stored
            switch: Switch target
        """
        stored_flows_box = self.stored_flows.copy()
        # if the flow has a destination dpid it can be stored.
        if not switch:
            log.info('The Flow cannot be stored, the destination switch '
                     f'have not been specified: {switch}')
            return

        new_flow = {}
        flow_list = []
        new_flow['command'] = command
        new_flow['flow'] = flow

        if switch.id not in stored_flows_box:
            # Switch not stored, add to box.
            flow_list.append(new_flow)
            stored_flows_box[switch.id] = {"flow_list": flow_list}
        else:
            stored_flows = stored_flows_box[switch.id].get('flow_list', [])
            # Check if flow already stored
            for stored_flow in stored_flows:
                if self._is_flows_equal(new_flow, stored_flow):
                    if stored_flow['command'] == new_flow['command']:
                        log.debug('Data already stored.')
                        return
                    # Command conflict. Remove the old flow.
                    # Stored instruction to install a flow but, the new is to
                    # remove.
                    stored_flow['command'] = new_flow.get('command')
                    stored_flows.remove(stored_flow)
                    break

            stored_flows.append(new_flow)
            stored_flows_box[switch.id]['flow_list'] = stored_flows

        stored_flows_box['id'] = 'flow_persistence'
        self.storehouse.save_flow(stored_flows_box)
        del stored_flows_box['id']
        self.stored_flows = stored_flows_box.copy()

    @rest('v2/flows')
    @rest('v2/flows/<dpid>')
    def list(self, dpid=None):
        """Retrieve all flows from a switch identified by dpid.

        If no dpid is specified, return all flows from all switches.
        """
        if dpid is None:
            switches = self.controller.switches.values()
        else:
            switches = [self.controller.get_switch_by_dpid(dpid)]

        switch_flows = {}

        for switch in switches:
            flows_dict = [flow.as_dict() for flow in switch.flows]
            switch_flows[switch.dpid] = {'flows': flows_dict}

        return jsonify(switch_flows)

    @rest('v2/flows', methods=['POST'])
    @rest('v2/flows/<dpid>', methods=['POST'])
    def add(self, dpid=None):
        """Install new flows in the switch identified by dpid.

        If no dpid is specified, install flows in all switches.
        """
        return self._send_flow_mods_from_request(dpid, "add")

    @rest('v2/delete', methods=['POST'])
    @rest('v2/delete/<dpid>', methods=['POST'])
    @rest('v2/flows', methods=['DELETE'])
    @rest('v2/flows/<dpid>', methods=['DELETE'])
    def delete(self, dpid=None):
        """Delete existing flows in the switch identified by dpid.

        If no dpid is specified, delete flows from all switches.
        """
        return self._send_flow_mods_from_request(dpid, "delete")

    def _get_all_switches_enabled(self):
        """Get a list of all switches enabled."""
        switches = self.controller.switches.values()
        return [switch for switch in switches if switch.is_enabled()]

    def _send_flow_mods_from_request(self, dpid, command, flows_dict=None):
        """Install FlowsMods from request."""
        if flows_dict is None:
            flows_dict = request.get_json()
            if flows_dict is None:
                return jsonify({"response": 'flows dict is none.'}), 404

        if dpid:
            switch = self.controller.get_switch_by_dpid(dpid)
            if not switch:
                return jsonify({"response": 'dpid not found.'}), 404
            elif switch.is_enabled() is False:
                return jsonify({"response": 'switch is disabled.'}), 404
            else:
                self._install_flows(command, flows_dict, [switch])
        else:
            self._install_flows(command, flows_dict,
                                self._get_all_switches_enabled())

        return jsonify({"response": "FlowMod Messages Sent"})

    def _install_flows(self, command, flows_dict, switches=[]):
        """Execute all procedures to install flows in the switches.

        Args:
            command: Flow command to be installed
            flows_dict: Dictionary with flows to be installed in the switches.
            switches: A list of switches
        """
        for switch in switches:
            serializer = FlowFactory.get_class(switch)
            flows = flows_dict.get('flows', [])
            for flow_dict in flows:
                flow = serializer.from_dict(flow_dict, switch)
                if command == "delete":
                    flow_mod = flow.as_of_delete_flow_mod()
                elif command == "add":
                    flow_mod = flow.as_of_add_flow_mod()
                else:
                    raise InvalidCommandError
                self._send_flow_mod(flow.switch, flow_mod)
                self._add_flow_mod_sent(flow_mod.header.xid, flow, command)

                self._send_napp_event(switch, flow, command)
                self._store_changed_flows(command, flow_dict, switch)

    def _add_flow_mod_sent(self, xid, flow, command):
        """Add the flow mod to the list of flow mods sent."""
        if len(self._flow_mods_sent) >= self._flow_mods_sent_max_size:
            self._flow_mods_sent.popitem(last=False)
        self._flow_mods_sent[xid] = (flow, command)

    def _send_flow_mod(self, switch, flow_mod):
        event_name = 'kytos/flow_manager.messages.out.ofpt_flow_mod'

        content = {'destination': switch.connection,
                   'message': flow_mod}

        event = KytosEvent(name=event_name, content=content)
        self.controller.buffers.msg_out.put(event)

    def _send_napp_event(self, switch, flow, command, **kwargs):
        """Send an Event to other apps informing about a FlowMod."""
        if command == 'add':
            name = 'kytos/flow_manager.flow.added'
        elif command == 'delete':
            name = 'kytos/flow_manager.flow.removed'
        elif command == 'error':
            name = 'kytos/flow_manager.flow.error'
        else:
            raise InvalidCommandError
        content = {'datapath': switch,
                   'flow': flow}
        content.update(kwargs)
        event_app = KytosEvent(name, content)
        self.controller.buffers.app.put(event_app)

    @listen_to('.*.of_core.*.ofpt_error')
    def handle_errors(self, event):
        """Receive OpenFlow error and send a event.

        The event is sent only if the error is related to a request made
        by flow_manager.
        """
        xid = event.content["message"].header.xid.value
        error_type = event.content["message"].error_type
        error_code = event.content["message"].code
        try:
            flow, error_command = self._flow_mods_sent[xid]
        except KeyError:
            pass
        else:
            self._send_napp_event(flow.switch, flow, 'error',
                                  error_command=error_command,
                                  error_type=error_type, error_code=error_code)


1		"""kytos/flow_manager NApp installs, lists and deletes switch flows."""
2	1	from collections import OrderedDict
3
4	1	from flask import jsonify, request
5
6	1	from kytos.core import KytosEvent, KytosNApp, log, rest
7	1	from kytos.core.helpers import listen_to
8	1	from napps.kytos.flow_manager.storehouse import StoreHouse
9	1	from napps.kytos.of_core.flow import FlowFactory
10
11	1	from .exceptions import InvalidCommandError
12	1	from .settings import FLOWS_DICT_MAX_SIZE
13
14
15	1	class Main(KytosNApp):
16		"""Main class to be used by Kytos controller."""
17
18	1	def setup(self):
19		"""Replace the 'init' method for the KytosApp subclass.
20
21		The setup method is automatically called by the run method.
22		Users shouldn't call this method directly.
23		"""
24	1	log.debug("flow-manager starting")
25	1	self._flow_mods_sent = OrderedDict()
26	1	self._flow_mods_sent_max_size = FLOWS_DICT_MAX_SIZE
27
28		# Format of stored data
29		# {"flow_persistence":{
30		# "dpid_str":{
31		# "flow_list":[
32		# {"command":<add\|delete>}
33		# "flow":{flow_dict},
34		# ]
35		# }
36		# }}
37		# client to load and save data in storehouse
38	1	self.storehouse = StoreHouse(self.controller)
39	1	self.stored_flows = {}
40	1	self.resent_flows = set()
41
42	1	def execute(self):
43		"""Run once on NApp 'start' or in a loop.
44
45		The execute method is called by the run method of KytosNApp class.
46		Users shouldn't call this method directly.
47		"""
48		self._load_flows()
49
50	1	def shutdown(self):
51		"""Shutdown routine of the NApp."""
52		log.debug("flow-manager stopping")
53
54	1	@listen_to('kytos/topology.port.created')
55		def resend_stored_flows(self, event):
56		"""Resend stored Flows."""
57	1	dpid = str(event.content['switch'])
58	1	switch = self.controller.get_switch_by_dpid(dpid)
59		# This can be a problem because this code is running a thread
60	1	if dpid in self.resent_flows:
61		log.info(f'Flow already resended to Switch {dpid}')
62		return
63	1	if dpid in self.stored_flows:
64	1	flow_list = self.stored_flows[dpid]['flow_list']
65	1	for flow in flow_list:
66	1	command = flow['command']
67	1	flows_dict = {"flows": [flow['flow']]}
68	1	self._install_flows(command, flows_dict, [switch])
69	1	self.resent_flows.add(dpid)
70	1	log.info(f'Flows resent to Switch {dpid}')
71
72		# pylint: disable=attribute-defined-outside-init
73	1	def _load_flows(self):
74		"""Load stored flows."""
75	1	try:
76	1	data = self.storehouse.get_data()['flow_persistence']
77	1	if 'id' in data:
78		del data['id']
79	1	self.stored_flows = data
80
81		except KeyError as error:
82		log.debug(f'There are no flows to load: {error}')
83		else:
84	1	log.info('Flows loaded.')
85
86	1	@staticmethod
87		def _generate_match_fields(flows):
88		"""Generate flow match fields."""
89	1	match_fields = {}
90	1	flow = flows.get('flow')
91	1	print(flow)
92	1	for field in flow:
93	1	if 'priority' in field:
94	1	match_fields['priority'] = flow['priority']
95	1	if 'cookie' in field:
96	1	match_fields['cookie'] = flow['cookie']
97	1	if 'match' in field:
98	1	for m_field, value in flow['match'].items():
99	1	match_fields[m_field] = value
100	1	return match_fields
101
102	1	def _is_flows_equal(self, flow_1, flow_2):
103		"""Check if two flows are equal."""
104	1	flow_1_match_fields = self._generate_match_fields(flow_1)
105	1	flow_2_match_fields = self._generate_match_fields(flow_2)
106	1	if flow_1_match_fields == flow_2_match_fields:
107		return True
108	1	return False
109
110	1	def _store_changed_flows(self, command, flow, switch):
111		"""Store changed flows.
112
113		Args:
114		command: Flow command to be installed
115		flow: Flows to be stored
116		switch: Switch target
117		"""
118	1	stored_flows_box = self.stored_flows.copy()
119		# if the flow has a destination dpid it can be stored.
120	1	if not switch:
121		log.info('The Flow cannot be stored, the destination switch '
122		f'have not been specified: {switch}')
123		return
124
125	1	new_flow = {}
126	1	flow_list = []
127	1	new_flow['command'] = command
128	1	new_flow['flow'] = flow
129
130	1	if switch.id not in stored_flows_box:
131		# Switch not stored, add to box.
132	1	flow_list.append(new_flow)
133	1	stored_flows_box[switch.id] = {"flow_list": flow_list}
134		else:
135	1	stored_flows = stored_flows_box[switch.id].get('flow_list', [])
136		# Check if flow already stored
137	1	for stored_flow in stored_flows:
138	1	if self._is_flows_equal(new_flow, stored_flow):
139		if stored_flow['command'] == new_flow['command']:
140		log.debug('Data already stored.')
141		return
142		# Command conflict. Remove the old flow.
143		# Stored instruction to install a flow but, the new is to
144		# remove.
145		stored_flow['command'] = new_flow.get('command')
146		stored_flows.remove(stored_flow)
147		break
148
149	1	stored_flows.append(new_flow)
150	1	stored_flows_box[switch.id]['flow_list'] = stored_flows
151
152	1	stored_flows_box['id'] = 'flow_persistence'
153	1	self.storehouse.save_flow(stored_flows_box)
154	1	del stored_flows_box['id']
155	1	self.stored_flows = stored_flows_box.copy()
156
157	1	@rest('v2/flows')
158	1	@rest('v2/flows/<dpid>')
159	1	def list(self, dpid=None):
160		"""Retrieve all flows from a switch identified by dpid.
161
162		If no dpid is specified, return all flows from all switches.
163		"""
164	1	if dpid is None:
165	1	switches = self.controller.switches.values()
166		else:
167	1	switches = [self.controller.get_switch_by_dpid(dpid)]
168
169	1	switch_flows = {}
170
171	1	for switch in switches:
172	1	flows_dict = [flow.as_dict() for flow in switch.flows]
173	1	switch_flows[switch.dpid] = {'flows': flows_dict}
174
175	1	return jsonify(switch_flows)
176
177	1	@rest('v2/flows', methods=['POST'])
178	1	@rest('v2/flows/<dpid>', methods=['POST'])
179	1	def add(self, dpid=None):
180		"""Install new flows in the switch identified by dpid.
181
182		If no dpid is specified, install flows in all switches.
183		"""
184	1	return self._send_flow_mods_from_request(dpid, "add")
185
186	1	@rest('v2/delete', methods=['POST'])
187	1	@rest('v2/delete/<dpid>', methods=['POST'])
188	1	@rest('v2/flows', methods=['DELETE'])
189	1	@rest('v2/flows/<dpid>', methods=['DELETE'])
190	1	def delete(self, dpid=None):
191		"""Delete existing flows in the switch identified by dpid.
192
193		If no dpid is specified, delete flows from all switches.
194		"""
195	1	return self._send_flow_mods_from_request(dpid, "delete")
196
197	1	def _get_all_switches_enabled(self):
198		"""Get a list of all switches enabled."""
199	1	switches = self.controller.switches.values()
200	1	return [switch for switch in switches if switch.is_enabled()]
201
202	1	def _send_flow_mods_from_request(self, dpid, command, flows_dict=None):
203		"""Install FlowsMods from request."""
204	1	if flows_dict is None:
205	1	flows_dict = request.get_json()
206	1	if flows_dict is None:
207	1	return jsonify({"response": 'flows dict is none.'}), 404
208
209	1	if dpid:
210	1	switch = self.controller.get_switch_by_dpid(dpid)
211	1	if not switch:
212	1	return jsonify({"response": 'dpid not found.'}), 404
213	1	elif switch.is_enabled() is False:
214	1	return jsonify({"response": 'switch is disabled.'}), 404
215		else:
216	1	self._install_flows(command, flows_dict, [switch])
217		else:
218	1	self._install_flows(command, flows_dict,
219		self._get_all_switches_enabled())
220
221	1	return jsonify({"response": "FlowMod Messages Sent"})
222
223	1	def _install_flows(self, command, flows_dict, switches=[]):
224		"""Execute all procedures to install flows in the switches.
225
226		Args:
227		command: Flow command to be installed
228		flows_dict: Dictionary with flows to be installed in the switches.
229		switches: A list of switches
230		"""
231	1	for switch in switches:
232	1	serializer = FlowFactory.get_class(switch)
233	1	flows = flows_dict.get('flows', [])
234	1	for flow_dict in flows:
235	1	flow = serializer.from_dict(flow_dict, switch)
236	1	if command == "delete":
237		flow_mod = flow.as_of_delete_flow_mod()
238	1	elif command == "add":
239	1	flow_mod = flow.as_of_add_flow_mod()
240		else:
241		raise InvalidCommandError
242	1	self._send_flow_mod(flow.switch, flow_mod)
243	1	self._add_flow_mod_sent(flow_mod.header.xid, flow, command)
244
245	1	self._send_napp_event(switch, flow, command)
246	1	self._store_changed_flows(command, flow_dict, switch)
247
248	1	def _add_flow_mod_sent(self, xid, flow, command):
249		"""Add the flow mod to the list of flow mods sent."""
250	1	if len(self._flow_mods_sent) >= self._flow_mods_sent_max_size:
251		self._flow_mods_sent.popitem(last=False)
252	1	self._flow_mods_sent[xid] = (flow, command)
253
254	1	def _send_flow_mod(self, switch, flow_mod):
255	1	event_name = 'kytos/flow_manager.messages.out.ofpt_flow_mod'
256
257	1	content = {'destination': switch.connection,
258		'message': flow_mod}
259
260	1	event = KytosEvent(name=event_name, content=content)
261	1	self.controller.buffers.msg_out.put(event)
262
263	1	def _send_napp_event(self, switch, flow, command, **kwargs):
264		"""Send an Event to other apps informing about a FlowMod."""
265	1	if command == 'add':
266	1	name = 'kytos/flow_manager.flow.added'
267	1	elif command == 'delete':
268	1	name = 'kytos/flow_manager.flow.removed'
269	1	elif command == 'error':
270	1	name = 'kytos/flow_manager.flow.error'
271		else:
272		raise InvalidCommandError
273	1	content = {'datapath': switch,
274		'flow': flow}
275	1	content.update(kwargs)
276	1	event_app = KytosEvent(name, content)
277	1	self.controller.buffers.app.put(event_app)
278
279	1	@listen_to('..of_core..ofpt_error')
280		def handle_errors(self, event):
281		"""Receive OpenFlow error and send a event.
282
283		The event is sent only if the error is related to a request made
284		by flow_manager.
285		"""
286	1	xid = event.content["message"].header.xid.value
287	1	error_type = event.content["message"].error_type
288	1	error_code = event.content["message"].code
289	1	try:
290	1	flow, error_command = self._flow_mods_sent[xid]
291		except KeyError:
292		pass
293		else:
294	1	self._send_napp_event(flow.switch, flow, 'error',
295		error_command=error_command,
296		error_type=error_type, error_code=error_code)
297

kytos / flow_manager

Pull Request — master (#90)

build.main.Main._is_flows_equal() A

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