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Push — master ( c6f858...535d0d )
by Humberto
02:22
created

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
213 1
class ActionBase(ABC):
214
    """Base class for a flow action."""
215
216 1
    def as_dict(self):
217
        """Return a dict that can be dumped as JSON."""
218 1
        return vars(self)
219
220 1
    @classmethod
221
    def from_dict(cls, action_dict):
222
        """Return an action instance from attributes in a dictionary."""
223 1
        action = cls(None)
224 1
        for attr_name, value in action_dict.items():
225 1
            if hasattr(action, attr_name):
226 1
                setattr(action, attr_name, value)
227 1
        return action
228
229 1
    @abstractmethod
230
    def as_of_action(self):
231
        """Return a pyof action to be used by a FlowMod."""
232
233 1
    @classmethod
234 1
    @abstractmethod
235
    def from_of_action(cls, of_action):
236
        """Return an action from a pyof action."""
237
238
239 1
class ActionFactoryBase(ABC):
240
    """Deal with different implementations of ActionBase."""
241
242
    # key: action_type or pyof class, value: ActionBase child
243 1
    _action_class = {
244
        'output': None,
245
        'set_vlan': None,
246
        # pyof class: ActionBase child
247
    }
248
249 1
    @classmethod
250
    def from_dict(cls, action_dict):
251
        """Build the proper Action from a dictionary.
252
253
        Args:
254
            action_dict (dict): Action attributes.
255
        """
256 1
        action_type = action_dict.get('action_type')
257 1
        action_class = cls._action_class[action_type]
258 1
        return action_class.from_dict(action_dict) if action_class else None
259
260 1
    @classmethod
261
    def from_of_action(cls, of_action):
262
        """Build the proper Action from a pyof action.
263
264
        Args:
265
            of_action (pyof action): Action from python-openflow.
266
        """
267
        of_class = type(of_action)
268
        action_class = cls._action_class.get(of_class)
269
        return action_class.from_of_action(of_action) if action_class else None
270
271
272 1
class MatchBase:  # pylint: disable=too-many-instance-attributes
273
    """Base class with common high-level Match fields."""
274
275 1
    def __init__(self, in_port=None, dl_src=None, dl_dst=None, dl_vlan=None,
276
                 dl_vlan_pcp=None, dl_type=None, nw_proto=None, nw_src=None,
277
                 nw_dst=None, tp_src=None, tp_dst=None, in_phy_port=None,
278
                 ip_dscp=None, ip_ecn=None, udp_src=None, udp_dst=None,
279
                 sctp_src=None, sctp_dst=None, icmpv4_type=None,
280
                 icmpv4_code=None, arp_op=None, arp_spa=None, arp_tpa=None,
281
                 arp_sha=None, arp_tha=None, ipv6_src=None, ipv6_dst=None,
282
                 ipv6_flabel=None, icmpv6_type=None, icmpv6_code=None,
283
                 nd_tar=None, nd_sll=None, nd_tll=None, mpls_lab=None,
284
                 mpls_tc=None, mpls_bos=None, pbb_isid=None, v6_hdr=None,
285
                 metadata=None, tun_id=None):
286
        """Make it possible to set all attributes from the constructor."""
287
        # pylint: disable=too-many-arguments
288
        # pylint: disable=too-many-locals
289 1
        self.in_port = in_port
290 1
        self.dl_src = dl_src
291 1
        self.dl_dst = dl_dst
292 1
        self.dl_vlan = dl_vlan
293 1
        self.dl_vlan_pcp = dl_vlan_pcp
294 1
        self.dl_type = dl_type
295 1
        self.nw_proto = nw_proto
296 1
        self.nw_src = nw_src
297 1
        self.nw_dst = nw_dst
298 1
        self.tp_src = tp_src
299 1
        self.tp_dst = tp_dst
300 1
        self.in_phy_port = in_phy_port
301 1
        self.ip_dscp = ip_dscp
302 1
        self.ip_ecn = ip_ecn
303 1
        self.udp_src = udp_src
304 1
        self.udp_dst = udp_dst
305 1
        self.sctp_src = sctp_src
306 1
        self.sctp_dst = sctp_dst
307 1
        self.icmpv4_type = icmpv4_type
308 1
        self.icmpv4_code = icmpv4_code
309 1
        self.arp_op = arp_op
310 1
        self.arp_spa = arp_spa
311 1
        self.arp_tpa = arp_tpa
312 1
        self.arp_sha = arp_sha
313 1
        self.arp_tha = arp_tha
314 1
        self.ipv6_src = ipv6_src
315 1
        self.ipv6_dst = ipv6_dst
316 1
        self.ipv6_flabel = ipv6_flabel
317 1
        self.icmpv6_type = icmpv6_type
318 1
        self.icmpv6_code = icmpv6_code
319 1
        self.nd_tar = nd_tar
320 1
        self.nd_sll = nd_sll
321 1
        self.nd_tll = nd_tll
322 1
        self.mpls_lab = mpls_lab
323 1
        self.mpls_tc = mpls_tc
324 1
        self.mpls_bos = mpls_bos
325 1
        self.pbb_isid = pbb_isid
326 1
        self.v6_hdr = v6_hdr
327 1
        self.metadata = metadata
328 1
        self.tun_id = tun_id
329
330 1
    def as_dict(self):
331
        """Return a dictionary excluding ``None`` values."""
332 1
        return {k: v for k, v in self.__dict__.items() if v is not None}
333
334 1
    @classmethod
335
    def from_dict(cls, match_dict):
336
        """Return a Match instance from a dictionary."""
337 1
        match = cls()
338 1
        for key, value in match_dict.items():
339 1
            if key in match.__dict__:
340 1
                setattr(match, key, value)
341 1
        return match
342
343 1
    @classmethod
344 1
    @abstractmethod
345
    def from_of_match(cls, of_match):
346
        """Return a Match instance from a pyof Match."""
347
348 1
    @abstractmethod
349
    def as_of_match(self):
350
        """Return a python-openflow Match."""
351
352
353 1
class Stats:
354
    """Simple class to store statistics as attributes and values."""
355
356 1
    def as_dict(self):
357
        """Return a dict excluding attributes with ``None`` value."""
358 1
        return {attribute: value
359
                for attribute, value in vars(self).items()
360
                if value is not None}
361
362 1
    @classmethod
363
    def from_dict(cls, stats_dict):
364
        """Return a statistics object from a dictionary."""
365 1
        stats = cls()
366 1
        cls._update(stats, stats_dict.items())
367 1
        return stats
368
369 1
    @classmethod
370
    def from_of_flow_stats(cls, of_stats):
371
        """Create an instance from a pyof FlowStats."""
372
        stats = cls()
373
        stats.update(of_stats)
374
        return stats
375
376 1
    def update(self, of_stats):
377
        """Given a pyof stats object, update attributes' values.
378
379
        Avoid object creation and memory leak. pyof values are GenericType
380
        instances whose native values can be accessed by `.value`.
381
        """
382
        # Generator for GenericType values
383
        attr_name_value = ((attr_name, gen_type.value)
0 ignored issues
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Comprehensibility Best Practice introduced by
The variable attr_name does not seem to be defined.
Loading history...
384
                           for attr_name, gen_type in vars(of_stats).items()
385
                           if attr_name in vars(self))
386
        self._update(self, attr_name_value)
387
388 1
    @staticmethod
389
    def _update(obj, iterable):
390
        """From attribute name and value pairs, update ``obj``."""
391 1
        for attr_name, value in iterable:
392
            if hasattr(obj, attr_name):
393
                setattr(obj, attr_name, value)
394
395
396 1
class FlowStats(Stats):
397
    """Common fields for 1.0 and 1.3 FlowStats."""
398
399 1
    def __init__(self):
400
        """Initialize all statistics as ``None``."""
401 1
        self.byte_count = None
402 1
        self.duration_sec = None
403 1
        self.duration_nsec = None
404 1
        self.packet_count = None
405
406
407 1
class PortStats(Stats):  # pylint: disable=too-many-instance-attributes
408
    """Common fields for 1.0 and 1.3 PortStats."""
409
410 1
    def __init__(self):
411
        """Initialize all statistics as ``None``."""
412
        self.rx_packets = None
413
        self.tx_packets = None
414
        self.rx_bytes = None
415
        self.tx_bytes = None
416
        self.rx_dropped = None
417
        self.tx_dropped = None
418
        self.rx_errors = None
419
        self.tx_errors = None
420
        self.rx_frame_err = None
421
        self.rx_over_err = None
422
        self.rx_crc_err = None
423
        self.collisions = None
424