build.main.Main.delete() - 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 18:05 UTC

build.main.Main.delete() A

↳ Parent: build.main

Complexity

Conditions

Size

Total Lines	10
Code Lines	6

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	6
CRAP Score	1

Importance

Changes

Metric	Value
eloc	6
dl	0
loc	10
rs	10
c	0
b	0
f	0
ccs	6
cts	6
cp	1
cc	1
nop	2
crap	1

"""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":[
        #             {"match_storage":{},
        #             "data":{"flows":[]}}
        #         ]
        #     }
        # }}
        # 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.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 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 = {}
        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

                    # 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		# Format of stored data
29		# {"flow_persistence":{
30		# "dpid_str":{
31		# "flow_list":[
32		# {"match_storage":{},
33		# "data":{"flows":[]}}
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.debug(f'Flow already resended to Switch {dpid}')
62		return None
63	1	if dpid in self.stored_flows:
64	1	try:
65	1	flow_list = self.stored_flows[dpid]['flow_list']
66		except KeyError as error:
67		log.info(f'Error to resend stored flow: {error}')
68		return None
69	1	for flow in flow_list:
70	1	command = flow.get('command')
71	1	flows_dict = flow.get('data')
72	1	self._install_flows(command, flows_dict, [switch])
73	1	self.resent_flows.add(dpid)
74	1	log.info(f'Flows resent to Switch {dpid}')
75	1	return None
76
77		# pylint: disable=attribute-defined-outside-init
78	1	def _load_flows(self):
79		"""Load stored flows."""
80	1	try:
81	1	data = self.storehouse.get_data()['flow_persistence']
82	1	if 'id' in data:
83		del data['id']
84	1	self.stored_flows = data
85
86		except KeyError as error:
87		log.debug(f'There are no flows to load: {error}')
88		else:
89	1	log.info('Flows loaded.')
90
91	1	@staticmethod
92		def _generate_match_fields(flows):
93		"""Generate flow match fields."""
94	1	match_fields = {}
95	1	for fields in flows.get('flows', {}):
96	1	if 'priority' in fields:
97	1	match_fields['priority'] = fields['priority']
98	1	if 'cookie' in fields:
99	1	match_fields['cookie'] = fields['cookie']
100	1	if 'match' in fields:
101	1	for field, value in fields['match'].items():
102	1	match_fields[field] = value
103	1	return match_fields
104
105	1	def _store_changed_flows(self, command, flows, switches):
106		"""Store changed flows."""
107	1	store_box_updated = self.stored_flows.copy()
108		# if the flow has a destination dpid it can be stored.
109	1	if not switches:
110		log.info('The Flow cannot be stored, the destination Switches '
111		f'have not been specified: {switches}')
112		return None
113	1	for switch in switches:
114	1	new_flow = {}
115	1	flow_list = []
116	1	new_flow['command'] = command
117		# The fields to check if the flow is already stored.
118	1	new_flow['match_fields'] = self._generate_match_fields(flows)
119	1	new_flow['data'] = flows
120
121	1	if switch.id not in store_box_updated:
122		# Switch not stored, add to box.
123	1	flow_list.append(new_flow)
124	1	store_box_updated[switch.id] = {"flow_list": flow_list}
125	1	continue
126
127	1	stored_flows = store_box_updated[switch.id].get('flow_list', [])
128
129		# Check if flow already stored
130	1	for stored_flow in stored_flows:
131
132	1	new_flow_match_fields = new_flow.get('match_fields')
133	1	stored_flow_match_fields = stored_flow.get('match_fields')
134
135	1	if new_flow_match_fields == stored_flow_match_fields:
136
137		new_flow_command = new_flow.get('command')
138		stored_flow_command = stored_flow.get('command')
139
140		if new_flow_command == stored_flow_command:
141		log.debug('Data already stored.')
142		return None
143
144		# Command conflict. Remove the old flow.
145		# Example: Instruction to add new flow but exist
146		# a stored instruction to remove this flow.
147		# Remove old, and save the new instruction.
148		stored_flow['command'] = new_flow.get('command')
149		stored_flows.remove(stored_flow)
150		break
151
152	1	stored_flows.append(new_flow)
153	1	store_box_updated[switch.id]['flow_list'] = stored_flows
154
155	1	store_box_updated['id'] = 'flow_persistence'
156	1	self.storehouse.save_flow(store_box_updated)
157	1	del store_box_updated['id']
158	1	self.stored_flows = store_box_updated.copy()
159	1	return None
160
161	1	@rest('v2/flows')
162	1	@rest('v2/flows/<dpid>')
163	1	def list(self, dpid=None):
164		"""Retrieve all flows from a switch identified by dpid.
165
166		If no dpid is specified, return all flows from all switches.
167		"""
168	1	if dpid is None:
169	1	switches = self.controller.switches.values()
170		else:
171	1	switches = [self.controller.get_switch_by_dpid(dpid)]
172
173	1	switch_flows = {}
174
175	1	for switch in switches:
176	1	flows_dict = [flow.as_dict() for flow in switch.flows]
177	1	switch_flows[switch.dpid] = {'flows': flows_dict}
178
179	1	return jsonify(switch_flows)
180
181	1	@rest('v2/flows', methods=['POST'])
182	1	@rest('v2/flows/<dpid>', methods=['POST'])
183	1	def add(self, dpid=None):
184		"""Install new flows in the switch identified by dpid.
185
186		If no dpid is specified, install flows in all switches.
187		"""
188	1	return self._send_flow_mods_from_request(dpid, "add")
189
190	1	@rest('v2/delete', methods=['POST'])
191	1	@rest('v2/delete/<dpid>', methods=['POST'])
192	1	@rest('v2/flows', methods=['DELETE'])
193	1	@rest('v2/flows/<dpid>', methods=['DELETE'])
194	1	def delete(self, dpid=None):
195		"""Delete existing flows in the switch identified by dpid.
196
197		If no dpid is specified, delete flows from all switches.
198		"""
199	1	return self._send_flow_mods_from_request(dpid, "delete")
200
201	1	def _get_all_switches_enabled(self):
202		"""Get a list of all switches enabled."""
203	1	switches = self.controller.switches.values()
204	1	return [switch for switch in switches if switch.is_enabled()]
205
206	1	def _send_flow_mods_from_request(self, dpid, command, flows_dict=None):
207		"""Install FlowsMods from request."""
208	1	if flows_dict is None:
209	1	flows_dict = request.get_json()
210	1	if flows_dict is None:
211	1	return jsonify({"response": 'flows dict is none.'}), 404
212
213	1	if dpid:
214	1	switch = self.controller.get_switch_by_dpid(dpid)
215	1	if not switch:
216	1	return jsonify({"response": 'dpid not found.'}), 404
217	1	elif switch.is_enabled() is False:
218	1	return jsonify({"response": 'switch is disabled.'}), 404
219		else:
220	1	self._install_flows(command, flows_dict, [switch])
221		else:
222	1	self._install_flows(command, flows_dict,
223		self._get_all_switches_enabled())
224
225	1	return jsonify({"response": "FlowMod Messages Sent"})
226
227	1	def _install_flows(self, command, flows_dict, switches=[]):
228		"""Execute all procedures to install flows in the switches.
229
230		Args:
231		command: Flow command to be installed
232		flows_dict: Dictionary with flows to be installed in the switches.
233		switches: A list of switches
234		"""
235	1	for switch in switches:
236	1	serializer = FlowFactory.get_class(switch)
237	1	flows = flows_dict.get('flows', [])
238	1	for flow_dict in flows:
239	1	flow = serializer.from_dict(flow_dict, switch)
240	1	if command == "delete":
241		flow_mod = flow.as_of_delete_flow_mod()
242	1	elif command == "add":
243	1	flow_mod = flow.as_of_add_flow_mod()
244		else:
245		raise InvalidCommandError
246	1	self._send_flow_mod(flow.switch, flow_mod)
247	1	self._add_flow_mod_sent(flow_mod.header.xid, flow)
248
249	1	self._send_napp_event(switch, flow, command)
250	1	self._store_changed_flows(command, flows_dict, switches)
251
252	1	def _add_flow_mod_sent(self, xid, flow):
253		"""Add the flow mod to the list of flow mods sent."""
254	1	if len(self._flow_mods_sent) >= self._flow_mods_sent_max_size:
255		self._flow_mods_sent.popitem(last=False)
256	1	self._flow_mods_sent[xid] = flow
257
258	1	def _send_flow_mod(self, switch, flow_mod):
259	1	event_name = 'kytos/flow_manager.messages.out.ofpt_flow_mod'
260
261	1	content = {'destination': switch.connection,
262		'message': flow_mod}
263
264	1	event = KytosEvent(name=event_name, content=content)
265	1	self.controller.buffers.msg_out.put(event)
266
267	1	def _send_napp_event(self, switch, flow, command, **kwargs):
268		"""Send an Event to other apps informing about a FlowMod."""
269	1	if command == 'add':
270	1	name = 'kytos/flow_manager.flow.added'
271	1	elif command == 'delete':
272	1	name = 'kytos/flow_manager.flow.removed'
273	1	elif command == 'error':
274	1	name = 'kytos/flow_manager.flow.error'
275		else:
276		raise InvalidCommandError
277	1	content = {'datapath': switch,
278		'flow': flow}
279	1	content.update(kwargs)
280	1	event_app = KytosEvent(name, content)
281	1	self.controller.buffers.app.put(event_app)
282
283	1	@listen_to('..of_core..ofpt_error')
284		def handle_errors(self, event):
285		"""Receive OpenFlow error and send a event.
286
287		The event is sent only if the error is related to a request made
288		by flow_manager.
289		"""
290	1	xid = event.content["message"].header.xid.value
291	1	error_type = event.content["message"].error_type
292	1	error_code = event.content["message"].code
293	1	try:
294	1	flow = self._flow_mods_sent[xid]
295		except KeyError:
296		pass
297		else:
298	1	self._send_napp_event(flow.switch, flow, 'error',
299		error_type=error_type, error_code=error_code)
300

kytos / flow_manager

Pull Request — master (#90)

build.main.Main.delete() A

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