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build.flow.MatchBase.__init__()   B

Complexity

Conditions 1

Size

Total Lines 54
Code Lines 51

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 41
CRAP Score 1

Importance

Changes 0
Metric Value
eloc 51
dl 0
loc 54
ccs 41
cts 41
cp 1
rs 8.6036
c 0
b 0
f 0
cc 1
nop 41
crap 1

How to fix   Long Method    Many Parameters   

Long Method

Small methods make your code easier to understand, in particular if combined with a good name. Besides, if your method is small, finding a good name is usually much easier.

For example, if you find yourself adding comments to a method's body, this is usually a good sign to extract the commented part to a new method, and use the comment as a starting point when coming up with a good name for this new method.

Commonly applied refactorings include:

Many Parameters

Methods with many parameters are not only hard to understand, but their parameters also often become inconsistent when you need more, or different data.

There are several approaches to avoid long parameter lists:

1
"""High-level abstraction for Flows of multiple OpenFlow versions.
2
3
Use common fields of FlowStats/FlowMod of supported OF versions. ``match`` and
4
``actions`` fields are different, so Flow, Action and Match related classes are
5
inherited in v0x01 and v0x04 modules.
6
"""
7 1
import json
8 1
from abc import ABC, abstractmethod
9 1
from hashlib import md5
10
11
# Note: FlowModCommand is the same in both v0x01 and v0x04
12 1
from pyof.v0x04.controller2switch.flow_mod import FlowModCommand
13
14 1
from napps.kytos.of_core import v0x01, v0x04
15
16
17 1
class FlowFactory(ABC):  # pylint: disable=too-few-public-methods
18
    """Choose the correct Flow according to OpenFlow version."""
19
20 1
    @classmethod
21
    def from_of_flow_stats(cls, of_flow_stats, switch):
22
        """Return a Flow for the switch OpenFlow version."""
23 1
        flow_class = cls.get_class(switch)
24 1
        return flow_class.from_of_flow_stats(of_flow_stats, switch)
25
26 1
    @staticmethod
27
    def get_class(switch):
28
        """Return the Flow class for the switch OF version."""
29 1
        of_version = switch.connection.protocol.version
30 1
        if of_version == 0x01:
31 1
            return v0x01.flow.Flow
32 1
        if of_version == 0x04:
33 1
            return v0x04.flow.Flow
34
        raise NotImplementedError(f'Unsupported OpenFlow version {of_version}')
35
36
37 1
class FlowBase(ABC):  # pylint: disable=too-many-instance-attributes
38
    """Class to abstract a Flow to switches.
39
40
    This class represents a Flow installed or to be installed inside the
41
    switch. A flow, in this case is represented by a Match object and a set of
42
    actions that should occur in case any match happen.
43
    """
44
45
    # of_version number: 0x01, 0x04
46 1
    of_version = None
47
48
    # Subclasses must set their version-specific classes
49 1
    _action_factory = None
50 1
    _flow_mod_class = None
51 1
    _match_class = None
52
53 1
    def __init__(self, switch, table_id=0xff, match=None, priority=0x8000,
54
                 idle_timeout=0, hard_timeout=0, cookie=0, actions=None,
55
                 stats=None):
56
        """Assign parameters to attributes.
57
58
        Args:
59
            switch (kytos.core.switch.Switch): Switch ID is used to uniquely
60
                identify a flow.
61
            table_id (int): The index of a single table or 0xff for all tables.
62
            match (|match|): Match object.
63
            priority (int): Priority level of flow entry.
64
            idle_timeout (int): Idle time before discarding, in seconds.
65
            hard_timeout (int): Max time before discarding, in seconds.
66
            cookie (int): Opaque controller-issued identifier.
67
            actions (|list_of_actions|): List of actions to apply.
68
            stats (Stats): Latest flow statistics.
69
        """
70
        # pylint: disable=too-many-arguments,too-many-locals
71 1
        self.switch = switch
72 1
        self.table_id = table_id
73
        # Disable not-callable error as subclasses set a class
74 1
        self.match = match or self._match_class()  # pylint: disable=E1102
75 1
        self.priority = priority
76 1
        self.idle_timeout = idle_timeout
77 1
        self.hard_timeout = hard_timeout
78 1
        self.cookie = cookie
79 1
        self.actions = actions or []
80 1
        self.stats = stats or FlowStats()  # pylint: disable=E1102
81
82 1
    @property
83
    def id(self):  # pylint: disable=invalid-name
84
        """Return this flow unique identifier.
85
86
        Calculate an md5 hash based on this object's modified json string. The
87
        json for ID calculation excludes ``stats`` attribute that changes over
88
        time.
89
90
        Returns:
91
            str: Flow unique identifier (md5sum).
92
93
        """
94 1
        flow_str = self.as_json(sort_keys=True, include_id=False)
95 1
        md5sum = md5()
96 1
        md5sum.update(flow_str.encode('utf-8'))
97 1
        return md5sum.hexdigest()
98
99 1
    def as_dict(self, include_id=True):
100
        """Return the Flow as a serializable Python dictionary.
101
102
        Args:
103
            include_id (bool): Default is ``True``. Internally, it is set to
104
                ``False`` when calculating the flow ID that is based in this
105
                dictionary's JSON string.
106
107
        Returns:
108
            dict: Serializable dictionary.
109
110
        """
111 1
        flow_dict = {
112
            'switch': self.switch.id,
113
            'table_id': self.table_id,
114
            'match': self.match.as_dict(),
115
            'priority': self.priority,
116
            'idle_timeout': self.idle_timeout,
117
            'hard_timeout': self.hard_timeout,
118
            'cookie': self.cookie,
119
            'actions': [action.as_dict() for action in self.actions]}
120 1
        if include_id:
121
            # Avoid infinite recursion
122 1
            flow_dict['id'] = self.id
123
            # Remove statistics that change over time
124 1
            flow_dict['stats'] = self.stats.as_dict()
125
126 1
        return flow_dict
127
128 1
    @classmethod
129
    def from_dict(cls, flow_dict, switch):
130
        """Return an instance with values from ``flow_dict``."""
131 1
        flow = cls(switch)
132
133
        # Set attributes found in ``flow_dict``
134 1
        for attr_name, attr_value in flow_dict.items():
135 1
            if attr_name in vars(flow):
136 1
                setattr(flow, attr_name, attr_value)
137
138 1
        flow.switch = switch
139 1
        if 'stats' in flow_dict:
140 1
            flow.stats = FlowStats.from_dict(flow_dict['stats'])
141
142
        # Version-specific attributes
143 1
        if 'match' in flow_dict:
144 1
            flow.match = cls._match_class.from_dict(flow_dict['match'])
145 1
        if 'actions' in flow_dict:
146 1
            flow.actions = []
147 1
            for action_dict in flow_dict['actions']:
148 1
                action = cls._action_factory.from_dict(action_dict)
149 1
                if action:
150 1
                    flow.actions.append(action)
151
152 1
        return flow
153
154 1
    def as_json(self, sort_keys=False, include_id=True):
155
        """Return the representation of a flow in JSON format.
156
157
        Args:
158
            sort_keys (bool): ``False`` by default (Python's default). Sorting
159
                is used, for example, to calculate the flow ID.
160
            include_id (bool): ``True`` by default. Internally, the ID is not
161
                included while calculating it.
162
163
        Returns:
164
            string: Flow JSON string representation.
165
166
        """
167 1
        return json.dumps(self.as_dict(include_id), sort_keys=sort_keys)
168
169 1
    def as_of_add_flow_mod(self):
170
        """Return an OpenFlow add FlowMod."""
171 1
        return self._as_of_flow_mod(FlowModCommand.OFPFC_ADD)
172
173 1
    def as_of_delete_flow_mod(self):
174
        """Return an OpenFlow delete FlowMod."""
175 1
        return self._as_of_flow_mod(FlowModCommand.OFPFC_DELETE)
176
177 1
    @abstractmethod
178
    def _as_of_flow_mod(self, command):
179
        """Return a pyof FlowMod with given ``command``."""
180
        # Disable not-callable error as subclasses will set a class
181 1
        flow_mod = self._flow_mod_class()  # pylint: disable=E1102
182 1
        flow_mod.match = self.match.as_of_match()
183 1
        flow_mod.cookie = self.cookie
184 1
        flow_mod.command = command
185 1
        flow_mod.idle_timeout = self.idle_timeout
186 1
        flow_mod.hard_timeout = self.hard_timeout
187 1
        flow_mod.priority = self.priority
188 1
        return flow_mod
189
190 1
    @staticmethod
191 1
    @abstractmethod
192
    def _get_of_actions(of_flow_stats):
193
        """Return pyof actions from pyof FlowStats."""
194
195 1
    @classmethod
196
    def from_of_flow_stats(cls, of_flow_stats, switch):
197
        """Create a flow with latest stats based on pyof FlowStats."""
198
        of_actions = cls._get_of_actions(of_flow_stats)
199
        actions = (cls._action_factory.from_of_action(of_action)
0 ignored issues
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200
                   for of_action in of_actions)
201
        non_none_actions = [action for action in actions if action]
202
        return cls(switch,
203
                   table_id=of_flow_stats.table_id.value,
204
                   match=cls._match_class.from_of_match(of_flow_stats.match),
205
                   priority=of_flow_stats.priority.value,
206
                   idle_timeout=of_flow_stats.idle_timeout.value,
207
                   hard_timeout=of_flow_stats.hard_timeout.value,
208
                   cookie=of_flow_stats.cookie.value,
209
                   actions=non_none_actions,
210
                   stats=FlowStats.from_of_flow_stats(of_flow_stats))
211
212 1
    def __eq__(self, other):
213 1
        include_id = False
214 1
        if not isinstance(other, self.__class__):
215 1
            raise ValueError(f'Error comparing flows: {other} is not '
216
                             f'an instance of {self.__class__}')
217
218 1
        return self.as_dict(include_id) == other.as_dict(include_id)
219
220
221 1
class ActionBase(ABC):
222
    """Base class for a flow action."""
223
224 1
    def as_dict(self):
225
        """Return a dict that can be dumped as JSON."""
226 1
        return vars(self)
227
228 1
    @classmethod
229
    def from_dict(cls, action_dict):
230
        """Return an action instance from attributes in a dictionary."""
231 1
        action = cls(None)
232 1
        for attr_name, value in action_dict.items():
233 1
            if hasattr(action, attr_name):
234 1
                setattr(action, attr_name, value)
235 1
        return action
236
237 1
    @abstractmethod
238
    def as_of_action(self):
239
        """Return a pyof action to be used by a FlowMod."""
240
241 1
    @classmethod
242 1
    @abstractmethod
243
    def from_of_action(cls, of_action):
244
        """Return an action from a pyof action."""
245
246
247 1
class ActionFactoryBase(ABC):
248
    """Deal with different implementations of ActionBase."""
249
250
    # key: action_type or pyof class, value: ActionBase child
251 1
    _action_class = {
252
        'output': None,
253
        'set_vlan': None,
254
        # pyof class: ActionBase child
255
    }
256
257 1
    @classmethod
258
    def from_dict(cls, action_dict):
259
        """Build the proper Action from a dictionary.
260
261
        Args:
262
            action_dict (dict): Action attributes.
263
        """
264 1
        action_type = action_dict.get('action_type')
265 1
        action_class = cls._action_class[action_type]
266 1
        return action_class.from_dict(action_dict) if action_class else None
267
268 1
    @classmethod
269
    def from_of_action(cls, of_action):
270
        """Build the proper Action from a pyof action.
271
272
        Args:
273
            of_action (pyof action): Action from python-openflow.
274
        """
275
        of_class = type(of_action)
276
        action_class = cls._action_class.get(of_class)
277
        return action_class.from_of_action(of_action) if action_class else None
278
279
280 1
class MatchBase:  # pylint: disable=too-many-instance-attributes
281
    """Base class with common high-level Match fields."""
282
283 1
    def __init__(self, in_port=None, dl_src=None, dl_dst=None, dl_vlan=None,
284
                 dl_vlan_pcp=None, dl_type=None, nw_proto=None, nw_src=None,
285
                 nw_dst=None, tp_src=None, tp_dst=None, in_phy_port=None,
286
                 ip_dscp=None, ip_ecn=None, udp_src=None, udp_dst=None,
287
                 sctp_src=None, sctp_dst=None, icmpv4_type=None,
288
                 icmpv4_code=None, arp_op=None, arp_spa=None, arp_tpa=None,
289
                 arp_sha=None, arp_tha=None, ipv6_src=None, ipv6_dst=None,
290
                 ipv6_flabel=None, icmpv6_type=None, icmpv6_code=None,
291
                 nd_tar=None, nd_sll=None, nd_tll=None, mpls_lab=None,
292
                 mpls_tc=None, mpls_bos=None, pbb_isid=None, v6_hdr=None,
293
                 metadata=None, tun_id=None):
294
        """Make it possible to set all attributes from the constructor."""
295
        # pylint: disable=too-many-arguments
296
        # pylint: disable=too-many-locals
297 1
        self.in_port = in_port
298 1
        self.dl_src = dl_src
299 1
        self.dl_dst = dl_dst
300 1
        self.dl_vlan = dl_vlan
301 1
        self.dl_vlan_pcp = dl_vlan_pcp
302 1
        self.dl_type = dl_type
303 1
        self.nw_proto = nw_proto
304 1
        self.nw_src = nw_src
305 1
        self.nw_dst = nw_dst
306 1
        self.tp_src = tp_src
307 1
        self.tp_dst = tp_dst
308 1
        self.in_phy_port = in_phy_port
309 1
        self.ip_dscp = ip_dscp
310 1
        self.ip_ecn = ip_ecn
311 1
        self.udp_src = udp_src
312 1
        self.udp_dst = udp_dst
313 1
        self.sctp_src = sctp_src
314 1
        self.sctp_dst = sctp_dst
315 1
        self.icmpv4_type = icmpv4_type
316 1
        self.icmpv4_code = icmpv4_code
317 1
        self.arp_op = arp_op
318 1
        self.arp_spa = arp_spa
319 1
        self.arp_tpa = arp_tpa
320 1
        self.arp_sha = arp_sha
321 1
        self.arp_tha = arp_tha
322 1
        self.ipv6_src = ipv6_src
323 1
        self.ipv6_dst = ipv6_dst
324 1
        self.ipv6_flabel = ipv6_flabel
325 1
        self.icmpv6_type = icmpv6_type
326 1
        self.icmpv6_code = icmpv6_code
327 1
        self.nd_tar = nd_tar
328 1
        self.nd_sll = nd_sll
329 1
        self.nd_tll = nd_tll
330 1
        self.mpls_lab = mpls_lab
331 1
        self.mpls_tc = mpls_tc
332 1
        self.mpls_bos = mpls_bos
333 1
        self.pbb_isid = pbb_isid
334 1
        self.v6_hdr = v6_hdr
335 1
        self.metadata = metadata
336 1
        self.tun_id = tun_id
337
338 1
    def as_dict(self):
339
        """Return a dictionary excluding ``None`` values."""
340 1
        return {k: v for k, v in self.__dict__.items() if v is not None}
341
342 1
    @classmethod
343
    def from_dict(cls, match_dict):
344
        """Return a Match instance from a dictionary."""
345 1
        match = cls()
346 1
        for key, value in match_dict.items():
347 1
            if key in match.__dict__:
348 1
                setattr(match, key, value)
349 1
        return match
350
351 1
    @classmethod
352 1
    @abstractmethod
353
    def from_of_match(cls, of_match):
354
        """Return a Match instance from a pyof Match."""
355
356 1
    @abstractmethod
357
    def as_of_match(self):
358
        """Return a python-openflow Match."""
359
360
361 1
class Stats:
362
    """Simple class to store statistics as attributes and values."""
363
364 1
    def as_dict(self):
365
        """Return a dict excluding attributes with ``None`` value."""
366 1
        return {attribute: value
367
                for attribute, value in vars(self).items()
368
                if value is not None}
369
370 1
    @classmethod
371
    def from_dict(cls, stats_dict):
372
        """Return a statistics object from a dictionary."""
373 1
        stats = cls()
374 1
        cls._update(stats, stats_dict.items())
375 1
        return stats
376
377 1
    @classmethod
378
    def from_of_flow_stats(cls, of_stats):
379
        """Create an instance from a pyof FlowStats."""
380
        stats = cls()
381
        stats.update(of_stats)
382
        return stats
383
384 1
    def update(self, of_stats):
385
        """Given a pyof stats object, update attributes' values.
386
387
        Avoid object creation and memory leak. pyof values are GenericType
388
        instances whose native values can be accessed by `.value`.
389
        """
390
        # Generator for GenericType values
391
        attr_name_value = ((attr_name, gen_type.value)
0 ignored issues
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Comprehensibility Best Practice introduced by
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Comprehensibility Best Practice introduced by
The variable gen_type does not seem to be defined.
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392
                           for attr_name, gen_type in vars(of_stats).items()
393
                           if attr_name in vars(self))
394
        self._update(self, attr_name_value)
395
396 1
    @staticmethod
397
    def _update(obj, iterable):
398
        """From attribute name and value pairs, update ``obj``."""
399 1
        for attr_name, value in iterable:
400
            if hasattr(obj, attr_name):
401
                setattr(obj, attr_name, value)
402
403
404 1
class FlowStats(Stats):
405
    """Common fields for 1.0 and 1.3 FlowStats."""
406
407 1
    def __init__(self):
408
        """Initialize all statistics as ``None``."""
409 1
        self.byte_count = None
410 1
        self.duration_sec = None
411 1
        self.duration_nsec = None
412 1
        self.packet_count = None
413
414
415 1
class PortStats(Stats):  # pylint: disable=too-many-instance-attributes
416
    """Common fields for 1.0 and 1.3 PortStats."""
417
418 1
    def __init__(self):
419
        """Initialize all statistics as ``None``."""
420
        self.rx_packets = None
421
        self.tx_packets = None
422
        self.rx_bytes = None
423
        self.tx_bytes = None
424
        self.rx_dropped = None
425
        self.tx_dropped = None
426
        self.rx_errors = None
427
        self.tx_errors = None
428
        self.rx_frame_err = None
429
        self.rx_over_err = None
430
        self.rx_crc_err = None
431
        self.collisions = None
432