build.main.Main._store_changed_flows() - Code Metrics - Inspection of "Add consistency" - kytos/flow_manager - Measure and Improve Code Quality continuously with Scrutinizer

Test Failed

Pull Request — master (#96)

by Jose

created 2020-11-16 17:55 UTC

build.main.Main._store_changed_flows() B

↳ Parent: build.main

Complexity

Conditions

Size

Total Lines	48
Code Lines	27

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	22
CRAP Score	6.0622

Importance

Changes

Metric	Value
cc	6
eloc	27
nop	4
dl	0
loc	48
ccs	22
cts	25
cp	0.88
crap	6.0622
rs	8.2986
c	0
b	0
f	0

"""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, CONSISTENCY_INTERVAL


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

        # Storehouse client to save and restore flow data:
        self.storehouse = StoreHouse(self.controller)

        # Format of stored flow data:
        # {'flow_persistence': {'dpid_str': {'flow_list': [
        #                                     {'command': '<add|delete>',
        #                                      'flow': {flow_dict}}]}}}
        self.stored_flows = {}
        self.resent_flows = set()
        self.execute_as_loop(CONSISTENCY_INTERVAL)

    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")

    def consistency_check(self):
        """Check the consistency of flows in each switch."""
        switches = self.controller.switches.values()

        for switch in switches:
            if switch.dpid in self.stored_flows:
                self.consistency_in_switch(switch)
            else:
                continue

    def consistency_in_switch(self, switch):
        """Check consistency for a specific switch."""
        switch_flows = {}

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

        dpid = switch.dpid

        flow_list = self.stored_flows[dpid]['flow_list']

        for stored_flow in flow_list:
            stored_flow = stored_flow['data']['flows'][0]
            for installed_flow in flows_dict:
                if self._is_equal_flows(stored_flow, installed_flow):
                    log.warning("A problem with consistency were dectected.")
                    command = stored_flow['command']
                    self._install_flows(command, stored_flow_data, [switch])


    # @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 None
    #     if dpid in self.stored_flows:
    #         flow_list = self.stored_flows[dpid]['flow_list']
    #         for flow in flow_list:
    #             command = flow.get('command')
    #             flows_dict = flow.get('data')
    #             self._install_flows(command, flows_dict, [switch])
    #         self.resent_flows.add(dpid)
    #         log.info(f'Flows resent to Switch {dpid}')
    #     return None

    # 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['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:
                match_fields.update(flow['match'])
        return match_fields

    def _is_equal_flows(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_equal_flows(new_flow, stored_flow):
                    if stored_flow['command'] == new_flow['command']:
                        log.debug('Data already stored.')
                        return
                    # Flow with inconsistency in "command" fields : Remove the
                    # old instruction. This happens when there is a stored
                    # instruction to install the flow, but the new instruction
                    # is to remove it. In this case, the old instruction is
                    # removed and the new one is stored.
                    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		from napps.kytos.of_core.flow import FlowFactory
10	1
11	1	from .exceptions import InvalidCommandError
12		from .settings import FLOWS_DICT_MAX_SIZE, CONSISTENCY_INTERVAL
13
14	1
15		class Main(KytosNApp):
16		"""Main class to be used by Kytos controller."""
17	1
18		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	1	"""
24	1	log.debug("flow-manager starting")
25	1	self._flow_mods_sent = OrderedDict()
26		self._flow_mods_sent_max_size = FLOWS_DICT_MAX_SIZE
27	1
28		# Storehouse client to save and restore flow data:
29		self.storehouse = StoreHouse(self.controller)
30
31		# Format of stored flow data:
32		# {'flow_persistence': {'dpid_str': {'flow_list': [
33		# {'command': '<add\|delete>',
34	1	# 'flow': {flow_dict}}]}}}
35		self.stored_flows = {}
36		self.resent_flows = set()
37		self.execute_as_loop(CONSISTENCY_INTERVAL)
38	1
39	1	def execute(self):
40	1	"""Run once on NApp 'start' or in a loop.
41
42		The execute method is called by the run method of KytosNApp class.
43		Users shouldn't call this method directly.
44		"""
45	1	self._load_flows()
46	1
47		def shutdown(self):
48	1	"""Shutdown routine of the NApp."""
49		log.debug("flow-manager stopping")
50	1
51		def consistency_check(self):
52	1	"""Check the consistency of flows in each switch."""
53	1	switches = self.controller.switches.values()
54	1
55		for switch in switches:
56	1	if switch.dpid in self.stored_flows:
57		self.consistency_in_switch(switch)
58	1	else:
59	1	continue
60	1
61		def consistency_in_switch(self, switch):
62		"""Check consistency for a specific switch."""
63		switch_flows = {}
64
65	1	flows_dict = [flow.as_dict() for flow in switch.flows]
66		switch_flows[switch.dpid] = {'flows': flows_dict}
67	1
68	1	dpid = switch.dpid
69	1
70	1	flow_list = self.stored_flows[dpid]['flow_list']
71	1
72		for stored_flow in flow_list:
73		stored_flow = stored_flow['data']['flows'][0]
74		for installed_flow in flows_dict:
75		if self._is_equal_flows(stored_flow, installed_flow):
76	1	log.warning("A problem with consistency were dectected.")
77		command = stored_flow['command']
78	1	self._install_flows(command, stored_flow_data, [switch])
		0 ignored issues – show Comprehensibility Best Practice introduced 2020-11-16 17:57 UTC by Report Bug Copy Issue Report The variable `stored_flow_data` does not seem to be defined. Loading history...
79
80	1	# @listen_to('kytos/topology.port.created')
81	1	# def resend_stored_flows(self, event):
82		# """Resend stored Flows."""
83	1	# dpid = str(event.content['switch'])
84		# switch = self.controller.get_switch_by_dpid(dpid)
85	1	# # This can be a problem because this code is running a thread
86		# if dpid in self.resent_flows:
87	1	# log.info(f'Flow already resended to Switch {dpid}')
88	1	# return None
89		# if dpid in self.stored_flows:
90	1	# flow_list = self.stored_flows[dpid]['flow_list']
91	1	# for flow in flow_list:
92	1	# command = flow.get('command')
93	1	# flows_dict = flow.get('data')
94	1	# self._install_flows(command, flows_dict, [switch])
95	1	# self.resent_flows.add(dpid)
96		# log.info(f'Flows resent to Switch {dpid}')
97	1	# return None
98
99	1	# pylint: disable=attribute-defined-outside-init
100		def _load_flows(self):
101		"""Load stored flows."""
102	1	try:
103		data = self.storehouse.get_data()['flow_persistence']
104	1	if 'id' in data:
105		del data['id']
106		self.stored_flows = data
107
108		except KeyError as error:
109		log.debug(f'There are no flows to load: {error}')
110		else:
111		log.info('Flows loaded.')
112	1
113	1	@staticmethod
114	1	def _generate_match_fields(flows):
115	1	"""Generate flow match fields."""
116	1	match_fields = {}
117	1	flow = flows['flow']
118		for field in flow:
119	1	if 'priority' in field:
120	1	match_fields['priority'] = flow['priority']
121		if 'cookie' in field:
122		match_fields['cookie'] = flow['cookie']
123	1	if 'match' in field:
124	1	match_fields.update(flow['match'])
125		return match_fields
126	1
127		def _is_equal_flows(self, flow_1, flow_2):
128	1	"""Check if two flows are equal."""
129		flow_1_match_fields = self._generate_match_fields(flow_1)
130	1	flow_2_match_fields = self._generate_match_fields(flow_2)
131		if flow_1_match_fields == flow_2_match_fields:
132	1	return True
133		return False
134	1
135	1	def _store_changed_flows(self, command, flow, switch):
136		"""Store changed flows.
137	1
138		Args:
139		command: Flow command to be installed
140	1	flow: Flows to be stored
141	1	switch: Switch target
142		"""
143	1	stored_flows_box = self.stored_flows.copy()
144		# if the flow has a destination dpid it can be stored.
145	1	if not switch:
146	1	log.info('The Flow cannot be stored, the destination switch '
147	1	f'have not been specified: {switch}')
148	1	return
149	1
150	1	new_flow = {}
151		flow_list = []
152		new_flow['command'] = command
153	1	new_flow['flow'] = flow
154
155	1	if switch.id not in stored_flows_box:
156	1	# Switch not stored, add to box.
157	1	flow_list.append(new_flow)
158		stored_flows_box[switch.id] = {"flow_list": flow_list}
159	1	else:
160		stored_flows = stored_flows_box[switch.id].get('flow_list', [])
161		# Check if flow already stored
162		for stored_flow in stored_flows:
163		if self._is_equal_flows(new_flow, stored_flow):
164		if stored_flow['command'] == new_flow['command']:
165		log.debug('Data already stored.')
166	1	return
167	1	# Flow with inconsistency in "command" fields : Remove the
168	1	# old instruction. This happens when there is a stored
169	1	# instruction to install the flow, but the new instruction
170	1	# is to remove it. In this case, the old instruction is
171		# removed and the new one is stored.
172		stored_flow['command'] = new_flow.get('command')
173		stored_flows.remove(stored_flow)
174	1	break
175
176		stored_flows.append(new_flow)
177		stored_flows_box[switch.id]['flow_list'] = stored_flows
178
179		stored_flows_box['id'] = 'flow_persistence'
180		self.storehouse.save_flow(stored_flows_box)
181		del stored_flows_box['id']
182		self.stored_flows = stored_flows_box.copy()
183
184		@rest('v2/flows')
185		@rest('v2/flows/<dpid>')
186		def list(self, dpid=None):
187		"""Retrieve all flows from a switch identified by dpid.
188
189		If no dpid is specified, return all flows from all switches.
190		"""
191		if dpid is None:
192		switches = self.controller.switches.values()
193		else:
194		switches = [self.controller.get_switch_by_dpid(dpid)]
195
196		switch_flows = {}
197
198		for switch in switches:
199		flows_dict = [flow.as_dict() for flow in switch.flows]
200		switch_flows[switch.dpid] = {'flows': flows_dict}
201
202		return jsonify(switch_flows)
203
204		@rest('v2/flows', methods=['POST'])
205		@rest('v2/flows/<dpid>', methods=['POST'])
206		def add(self, dpid=None):
207		"""Install new flows in the switch identified by dpid.
208
209		If no dpid is specified, install flows in all switches.
210		"""
211		return self._send_flow_mods_from_request(dpid, "add")
212
213		@rest('v2/delete', methods=['POST'])
214		@rest('v2/delete/<dpid>', methods=['POST'])
215		@rest('v2/flows', methods=['DELETE'])
216		@rest('v2/flows/<dpid>', methods=['DELETE'])
217		def delete(self, dpid=None):
218		"""Delete existing flows in the switch identified by dpid.
219
220		If no dpid is specified, delete flows from all switches.
221		"""
222		return self._send_flow_mods_from_request(dpid, "delete")
223
224		def _get_all_switches_enabled(self):
225		"""Get a list of all switches enabled."""
226		switches = self.controller.switches.values()
227		return [switch for switch in switches if switch.is_enabled()]
228
229		def _send_flow_mods_from_request(self, dpid, command, flows_dict=None):
230		"""Install FlowsMods from request."""
231		if flows_dict is None:
232		flows_dict = request.get_json()
233		if flows_dict is None:
234		return jsonify({"response": 'flows dict is none.'}), 404
235
236		if dpid:
237		switch = self.controller.get_switch_by_dpid(dpid)
238		if not switch:
239		return jsonify({"response": 'dpid not found.'}), 404
240		elif switch.is_enabled() is False:
241		return jsonify({"response": 'switch is disabled.'}), 404
242		else:
243		self._install_flows(command, flows_dict, [switch])
244		else:
245		self._install_flows(command, flows_dict,
246		self._get_all_switches_enabled())
247
248		return jsonify({"response": "FlowMod Messages Sent"})
249
250		def _install_flows(self, command, flows_dict, switches=[]):
251		"""Execute all procedures to install flows in the switches.
252
253		Args:
254		command: Flow command to be installed
255		flows_dict: Dictionary with flows to be installed in the switches.
256		switches: A list of switches
257		"""
258		for switch in switches:
259		serializer = FlowFactory.get_class(switch)
260		flows = flows_dict.get('flows', [])
261		for flow_dict in flows:
262		flow = serializer.from_dict(flow_dict, switch)
263		if command == "delete":
264		flow_mod = flow.as_of_delete_flow_mod()
265		elif command == "add":
266		flow_mod = flow.as_of_add_flow_mod()
267		else:
268		raise InvalidCommandError
269		self._send_flow_mod(flow.switch, flow_mod)
270		self._add_flow_mod_sent(flow_mod.header.xid, flow, command)
271
272		self._send_napp_event(switch, flow, command)
273		self._store_changed_flows(command, flow_dict, switch)
274
275		def _add_flow_mod_sent(self, xid, flow, command):
276		"""Add the flow mod to the list of flow mods sent."""
277		if len(self._flow_mods_sent) >= self._flow_mods_sent_max_size:
278		self._flow_mods_sent.popitem(last=False)
279		self._flow_mods_sent[xid] = (flow, command)
280
281		def _send_flow_mod(self, switch, flow_mod):
282		event_name = 'kytos/flow_manager.messages.out.ofpt_flow_mod'
283
284		content = {'destination': switch.connection,
285		'message': flow_mod}
286
287		event = KytosEvent(name=event_name, content=content)
288		self.controller.buffers.msg_out.put(event)
289
290		def _send_napp_event(self, switch, flow, command, **kwargs):
291		"""Send an Event to other apps informing about a FlowMod."""
292		if command == 'add':
293		name = 'kytos/flow_manager.flow.added'
294		elif command == 'delete':
295		name = 'kytos/flow_manager.flow.removed'
296		elif command == 'error':
297		name = 'kytos/flow_manager.flow.error'
298		else:
299		raise InvalidCommandError
300		content = {'datapath': switch,
301		'flow': flow}
302		content.update(kwargs)
303		event_app = KytosEvent(name, content)
304		self.controller.buffers.app.put(event_app)
305
306		@listen_to('..of_core..ofpt_error')
307		def handle_errors(self, event):
308		"""Receive OpenFlow error and send a event.
309
310		The event is sent only if the error is related to a request made
311		by flow_manager.
312		"""
313		xid = event.content["message"].header.xid.value
314		error_type = event.content["message"].error_type
315		error_code = event.content["message"].code
316		try:
317		flow, error_command = self._flow_mods_sent[xid]
318		except KeyError:
319		pass
320		else:
321		self._send_napp_event(flow.switch, flow, 'error',
322		error_command=error_command,
323		error_type=error_type, error_code=error_code)
324

kytos / flow_manager

Pull Request — master (#96)

build.main.Main._store_changed_flows() B

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