build.main.Main._resolve_inconsistency() - 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 2020-11-17 16:41 UTC

build.main.Main._resolve_inconsistency() A

↳ Parent: build.main

Complexity

Conditions

Size

Total Lines	5
Code Lines	4

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	5
CRAP Score	1

Importance

Changes

Metric	Value
cc	1
eloc	4
nop	5
dl	0
loc	5
ccs	5
cts	5
cp	1
crap	1
rs	10
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()
        if CONSISTENCY_INTERVAL > 0:
            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()

        if CONSISTENCY_INTERVAL > 0:
            self.consistency_check()

    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:
            command = stored_flow['command']

            # flow to send to switch and resolve the inconsistency
            flow = {'flows': [stored_flow['flow']]}

            if not self._is_flow_in_switch(flows_dict, stored_flow['flow']):
                if command == 'add':
                    msg = f'Flow forwarded to switch {dpid} to be installed.'
                    self._resolve_inconsistency(command, flow, [switch], msg)
            elif command == 'delete':
                msg = f'Flow forwarded to switch {dpid} to be deleted.'
                self._resolve_inconsistency(command, flow, [switch], msg)

    def _resolve_inconsistency(self, command, flow, switch, msg):
        """Forward flow to be installed resolving the inconsistency."""
        log.info('A problem with consistency were dectected.')
        self._install_flows(command, flow, switch)
        log.info(msg)

    def _is_flow_in_switch(self, switch_flows, flow):
        """Check if the flow is installed in switch."""
        for switch_flow in switch_flows:
            if self._is_equal_flows(flow, switch_flow):
                return True
        return False

    # def resend_stored_flows(self, event):
    # Add the new version here

    # 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(flow):
        """Generate flow match fields."""
        match_fields = {}
        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['flow'], stored_flow['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		if CONSISTENCY_INTERVAL > 0:
38	1	self.execute_as_loop(CONSISTENCY_INTERVAL)
39	1
40	1	def execute(self):
41		"""Run once on NApp 'start' or in a loop.
42
43		The execute method is called by the run method of KytosNApp class.
44		Users shouldn't call this method directly.
45	1	"""
46	1	self._load_flows()
47
48	1	if CONSISTENCY_INTERVAL > 0:
49		self.consistency_check()
50	1
51		def shutdown(self):
52	1	"""Shutdown routine of the NApp."""
53	1	log.debug("flow-manager stopping")
54	1
55		def consistency_check(self):
56	1	"""Check the consistency of flows in each switch."""
57		switches = self.controller.switches.values()
58	1
59	1	for switch in switches:
60	1	if switch.dpid in self.stored_flows:
61		self.consistency_in_switch(switch)
62		else:
63		continue
64
65	1	def consistency_in_switch(self, switch):
66		"""Check consistency for a specific switch."""
67	1	switch_flows = {}
68	1
69	1	flows_dict = [flow.as_dict() for flow in switch.flows]
70	1	switch_flows[switch.dpid] = {'flows': flows_dict}
71	1
72		dpid = switch.dpid
73
74		flow_list = self.stored_flows[dpid]['flow_list']
75
76	1	for stored_flow in flow_list:
77		command = stored_flow['command']
78	1
79		# flow to send to switch and resolve the inconsistency
80	1	flow = {'flows': [stored_flow['flow']]}
81	1
82		if not self._is_flow_in_switch(flows_dict, stored_flow['flow']):
83	1	if command == 'add':
84		msg = f'Flow forwarded to switch {dpid} to be installed.'
85	1	self._resolve_inconsistency(command, flow, [switch], msg)
86		elif command == 'delete':
87	1	msg = f'Flow forwarded to switch {dpid} to be deleted.'
88	1	self._resolve_inconsistency(command, flow, [switch], msg)
89
90	1	def _resolve_inconsistency(self, command, flow, switch, msg):
91	1	"""Forward flow to be installed resolving the inconsistency."""
92	1	log.info('A problem with consistency were dectected.')
93	1	self._install_flows(command, flow, switch)
94	1	log.info(msg)
95	1
96		def _is_flow_in_switch(self, switch_flows, flow):
97	1	"""Check if the flow is installed in switch."""
98		for switch_flow in switch_flows:
99	1	if self._is_equal_flows(flow, switch_flow):
100		return True
101		return False
102	1
103		# def resend_stored_flows(self, event):
104	1	# Add the new version here
105
106		# pylint: disable=attribute-defined-outside-init
107		def _load_flows(self):
108		"""Load stored flows."""
109		try:
110		data = self.storehouse.get_data()['flow_persistence']
111		if 'id' in data:
112	1	del data['id']
113	1	self.stored_flows = data
114	1
115	1	except KeyError as error:
116	1	log.debug(f'There are no flows to load: {error}')
117	1	else:
118		log.info('Flows loaded.')
119	1
120	1	@staticmethod
121		def _generate_match_fields(flow):
122		"""Generate flow match fields."""
123	1	match_fields = {}
124	1	for field in flow:
125		if 'priority' in field:
126	1	match_fields['priority'] = flow['priority']
127		if 'cookie' in field:
128	1	match_fields['cookie'] = flow['cookie']
129		if 'match' in field:
130	1	match_fields.update(flow['match'])
131		return match_fields
132	1
133		def _is_equal_flows(self, flow_1, flow_2):
134	1	"""Check if two flows are equal."""
135	1	flow_1_match_fields = self._generate_match_fields(flow_1)
136		flow_2_match_fields = self._generate_match_fields(flow_2)
137	1	if flow_1_match_fields == flow_2_match_fields:
138		return True
139		return False
140	1
141	1	def _store_changed_flows(self, command, flow, switch):
142		"""Store changed flows.
143	1
144		Args:
145	1	command: Flow command to be installed
146	1	flow: Flows to be stored
147	1	switch: Switch target
148	1	"""
149	1	stored_flows_box = self.stored_flows.copy()
150	1	# if the flow has a destination dpid it can be stored.
151		if not switch:
152		log.info('The Flow cannot be stored, the destination switch '
153	1	f'have not been specified: {switch}')
154		return
155	1
156	1	new_flow = {}
157	1	flow_list = []
158		new_flow['command'] = command
159	1	new_flow['flow'] = flow
160
161		if switch.id not in stored_flows_box:
162		# Switch not stored, add to box.
163		flow_list.append(new_flow)
164		stored_flows_box[switch.id] = {'flow_list': flow_list}
165		else:
166	1	stored_flows = stored_flows_box[switch.id].get('flow_list', [])
167	1	# Check if flow already stored
168	1	for stored_flow in stored_flows:
169	1	if self._is_equal_flows(new_flow['flow'], stored_flow['flow']):
170	1	if stored_flow['command'] == new_flow['command']:
171		log.debug('Data already stored.')
172		return
173		# Flow with inconsistency in "command" fields : Remove the
174	1	# old instruction. This happens when there is a stored
175		# instruction to install the flow, but the new instruction
176		# is to remove it. In this case, the old instruction is
177		# removed and the new one is stored.
178		stored_flow['command'] = new_flow.get('command')
179		stored_flows.remove(stored_flow)
180		break
181
182		stored_flows.append(new_flow)
183		stored_flows_box[switch.id]['flow_list'] = stored_flows
184
185		stored_flows_box['id'] = 'flow_persistence'
186		self.storehouse.save_flow(stored_flows_box)
187		del stored_flows_box['id']
188		self.stored_flows = stored_flows_box.copy()
189
190		@rest('v2/flows')
191		@rest('v2/flows/<dpid>')
192		def list(self, dpid=None):
193		"""Retrieve all flows from a switch identified by dpid.
194
195		If no dpid is specified, return all flows from all switches.
196		"""
197		if dpid is None:
198		switches = self.controller.switches.values()
199		else:
200		switches = [self.controller.get_switch_by_dpid(dpid)]
201
202		switch_flows = {}
203
204		for switch in switches:
205		flows_dict = [flow.as_dict() for flow in switch.flows]
206		switch_flows[switch.dpid] = {'flows': flows_dict}
207
208		return jsonify(switch_flows)
209
210		@rest('v2/flows', methods=['POST'])
211		@rest('v2/flows/<dpid>', methods=['POST'])
212		def add(self, dpid=None):
213		"""Install new flows in the switch identified by dpid.
214
215		If no dpid is specified, install flows in all switches.
216		"""
217		return self._send_flow_mods_from_request(dpid, "add")
218
219		@rest('v2/delete', methods=['POST'])
220		@rest('v2/delete/<dpid>', methods=['POST'])
221		@rest('v2/flows', methods=['DELETE'])
222		@rest('v2/flows/<dpid>', methods=['DELETE'])
223		def delete(self, dpid=None):
224		"""Delete existing flows in the switch identified by dpid.
225
226		If no dpid is specified, delete flows from all switches.
227		"""
228		return self._send_flow_mods_from_request(dpid, "delete")
229
230		def _get_all_switches_enabled(self):
231		"""Get a list of all switches enabled."""
232		switches = self.controller.switches.values()
233		return [switch for switch in switches if switch.is_enabled()]
234
235		def _send_flow_mods_from_request(self, dpid, command, flows_dict=None):
236		"""Install FlowsMods from request."""
237		if flows_dict is None:
238		flows_dict = request.get_json()
239		if flows_dict is None:
240		return jsonify({"response": 'flows dict is none.'}), 404
241
242		if dpid:
243		switch = self.controller.get_switch_by_dpid(dpid)
244		if not switch:
245		return jsonify({"response": 'dpid not found.'}), 404
246		elif switch.is_enabled() is False:
247		return jsonify({"response": 'switch is disabled.'}), 404
248		else:
249		self._install_flows(command, flows_dict, [switch])
250		else:
251		self._install_flows(command, flows_dict,
252		self._get_all_switches_enabled())
253
254		return jsonify({"response": "FlowMod Messages Sent"})
255
256		def _install_flows(self, command, flows_dict, switches=[]):
257		"""Execute all procedures to install flows in the switches.
258
259		Args:
260		command: Flow command to be installed
261		flows_dict: Dictionary with flows to be installed in the switches.
262		switches: A list of switches
263		"""
264		for switch in switches:
265		serializer = FlowFactory.get_class(switch)
266		flows = flows_dict.get('flows', [])
267		for flow_dict in flows:
268		flow = serializer.from_dict(flow_dict, switch)
269		if command == "delete":
270		flow_mod = flow.as_of_delete_flow_mod()
271		elif command == "add":
272		flow_mod = flow.as_of_add_flow_mod()
273		else:
274		raise InvalidCommandError
275		self._send_flow_mod(flow.switch, flow_mod)
276		self._add_flow_mod_sent(flow_mod.header.xid, flow, command)
277
278		self._send_napp_event(switch, flow, command)
279		self._store_changed_flows(command, flow_dict, switch)
280
281		def _add_flow_mod_sent(self, xid, flow, command):
282		"""Add the flow mod to the list of flow mods sent."""
283		if len(self._flow_mods_sent) >= self._flow_mods_sent_max_size:
284		self._flow_mods_sent.popitem(last=False)
285		self._flow_mods_sent[xid] = (flow, command)
286
287		def _send_flow_mod(self, switch, flow_mod):
288		event_name = 'kytos/flow_manager.messages.out.ofpt_flow_mod'
289
290		content = {'destination': switch.connection,
291		'message': flow_mod}
292
293		event = KytosEvent(name=event_name, content=content)
294		self.controller.buffers.msg_out.put(event)
295
296		def _send_napp_event(self, switch, flow, command, **kwargs):
297		"""Send an Event to other apps informing about a FlowMod."""
298		if command == 'add':
299		name = 'kytos/flow_manager.flow.added'
300		elif command == 'delete':
301		name = 'kytos/flow_manager.flow.removed'
302		elif command == 'error':
303		name = 'kytos/flow_manager.flow.error'
304		else:
305		raise InvalidCommandError
306		content = {'datapath': switch,
307		'flow': flow}
308		content.update(kwargs)
309		event_app = KytosEvent(name, content)
310		self.controller.buffers.app.put(event_app)
311
312		@listen_to('..of_core..ofpt_error')
313		def handle_errors(self, event):
314		"""Receive OpenFlow error and send a event.
315
316		The event is sent only if the error is related to a request made
317		by flow_manager.
318		"""
319		xid = event.content["message"].header.xid.value
320		error_type = event.content["message"].error_type
321		error_code = event.content["message"].code
322		try:
323		flow, error_command = self._flow_mods_sent[xid]
324		except KeyError:
325		pass
326		else:
327		self._send_napp_event(flow.switch, flow, 'error',
328		error_command=error_command,
329		error_type=error_type, error_code=error_code)
330

kytos / flow_manager

Pull Request — master (#96)

build.main.Main._resolve_inconsistency() A

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