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

Passed

Pull Request — master (#90)

by Humberto

created 2020-10-14 19:00 UTC

build.main.Main.shutdown() A

↳ Parent: build.main

Complexity

Conditions

Size

Total Lines	3
Code Lines	2

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	1
CRAP Score	1.125

Importance

Changes

Metric	Value
eloc	2
dl	0
loc	3
ccs	1
cts	2
cp	0.5
rs	10
c	0
b	0
f	0
cc	1
nop	1
crap	1.125

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

kytos / flow_manager

Pull Request — master (#90)

build.main.Main.shutdown() A

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