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

build.main.Main._send_flow_mod() A

↳ Parent: build.main

Complexity

Conditions

Size

Total Lines	8
Code Lines	6

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	5
CRAP Score	1

Importance

Changes

Metric	Value
eloc	6
dl	0
loc	8
rs	10
c	0
b	0
f	0
ccs	5
cts	5
cp	1
cc	1
nop	3
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

        # 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()

    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.info(f'Flow already resended to Switch {dpid}')
            return
        if dpid in self.stored_flows:
            flow_list = self.stored_flows[dpid]['flow_list']
            for flow in flow_list:
                command = flow['command']
                flows_dict = {"flows": [flow['flow']]}
                self._install_flows(command, flows_dict, [switch])
            self.resent_flows.add(dpid)
            log.info(f'Flows resent to Switch {dpid}')

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

kytos / flow_manager

Pull Request — master (#90)

build.main.Main._send_flow_mod() A

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