build.main.Main.resend_stored_flows() - 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 2020-10-22 15:03 UTC

build.main.Main.resend_stored_flows() B

↳ Parent: build.main

Complexity

Conditions

Size

Total Lines	22
Code Lines	20

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	14
CRAP Score	5.4558

Importance

Changes

Metric	Value
cc	5
eloc	20
nop	2
dl	0
loc	22
ccs	14
cts	19
cp	0.7368
crap	5.4558
rs	8.9332
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


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

        # object to save and load flows
        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.debug(f'Flow already resended to Switch {dpid}')
            return None
        if dpid in self.stored_flows:
            try:
                flow_list = self.stored_flows[dpid]['flow_list']
            except KeyError as error:
                log.info(f'Error to resend stored flow: {error}')
                return None
            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 resended 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.info(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 = {}
        for fields in flows.get('flows', {}):
            if 'priority' in fields:
                match_fields['priority'] = fields['priority']
            if 'cookie' in fields:
                match_fields['cookie'] = fields['cookie']
            if 'match' in fields:
                for field, value in fields['match'].items():
                    match_fields[field] = value
        return match_fields

    def _store_changed_flows(self, command, flows, switches):
        """Store changed flows."""
        store_box_updated = self.stored_flows.copy()
        # if the flow has a destination dpid it can be stored.
        if not switches:
            log.info('The Flow cannot be stored, the destination Switches '
                     f'have not been specified: {switches}')
            return None
        for switch in switches:
            new_flow = {}
            flow_list = []
            new_flow['command'] = command
            # The fields to check if the flow is already stored.
            new_flow['match_fields'] = self._generate_match_fields(flows)
            new_flow['data'] = flows

            if switch.id not in store_box_updated:
                # Switch not stored, add to box.
                flow_list.append(new_flow)
                store_box_updated[switch.id] = {"flow_list": flow_list}
                continue

            stored_flows = store_box_updated[switch.id].get('flow_list', [])

            # Check if flow already stored
            for stored_flow in stored_flows:

                new_flow_match_fields = new_flow.get('match_fields')
                stored_flow_match_fields = stored_flow.get('match_fields')

                if new_flow_match_fields == stored_flow_match_fields:

                    new_flow_command = new_flow.get('command')
                    stored_flow_command = stored_flow.get('command')

                    if new_flow_command == stored_flow_command:
                        log.debug('Data already stored.')
                        return None
                    else:
                        # Command conflict. Remove the old flow.
                        # Example: Instruction to add new flow but exist
                        # a stored instruction to remove this flow.
                        # Remove old, and save the new instruction.
                        stored_flow['command'] = new_flow.get('command')
                        stored_flows.remove(stored_flow)
                        break

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

        store_box_updated['id'] = 'flow_persistence'
        self.storehouse.save_flow(store_box_updated)
        del store_box_updated['id']
        self.stored_flows = store_box_updated.copy()
        return None

    @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)

                self._send_napp_event(switch, flow, command)
        self._store_changed_flows(command, flows_dict, switches)

    def _add_flow_mod_sent(self, xid, flow):
        """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

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

kytos / flow_manager

Pull Request — master (#90)

build.main.Main.resend_stored_flows() B

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