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02:11
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build.flow.FlowBase.__init__()   A

Complexity

Conditions 1

Size

Total Lines 28
Code Lines 12

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 10
CRAP Score 1

Importance

Changes 0
Metric Value
cc 1
eloc 12
nop 10
dl 0
loc 28
ccs 10
cts 10
cp 1
crap 1
rs 9.8
c 0
b 0
f 0

How to fix   Many Parameters   

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}')
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37 1
class FlowBase(ABC):  # pylint: disable=too-many-instance-attributes
38
    """Class to abstract a Flow to switches.
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    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
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    # 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.
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        Args:
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            switch (kytos.core.switch.Switch): Switch ID is used to uniquely
60
                identify a flow.
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            table_id (int): The index of a single table or 0xff for all tables.
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            match (|match|): Match object.
63
            priority (int): Priority level of flow entry.
64
            idle_timeout (int): Idle time before discarding, in seconds.
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            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.
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        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.
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        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.
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        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.
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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.
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157
        Args:
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            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.
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        Returns:
164
            string: Flow JSON string representation.
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        """
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)
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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,
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                   match=cls._match_class.from_of_match(of_flow_stats.match),
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                   priority=of_flow_stats.priority.value,
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                   idle_timeout=of_flow_stats.idle_timeout.value,
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                   hard_timeout=of_flow_stats.hard_timeout.value,
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                   cookie=of_flow_stats.cookie.value,
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                   actions=non_none_actions,
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                   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,
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                 ip_dscp=None, ip_ecn=None, udp_src=None, udp_dst=None,
279
                 icmpv4_type=None, icmpv4_code=None, arp_op=None,
280
                 ipv6_flabel=None, icmpv6_type=None, icmpv6_code=None,
281
                 nd_tar=None, nd_sll=None, nd_tll=None, pbb_isid=None,
282
                 v6_hdr=None):
283
        """Make it possible to set all attributes from the constructor."""
284
        # pylint: disable=too-many-arguments
285
        # pylint: disable=too-many-locals
286 1
        self.in_port = in_port
287 1
        self.dl_src = dl_src
288 1
        self.dl_dst = dl_dst
289 1
        self.dl_vlan = dl_vlan
290 1
        self.dl_vlan_pcp = dl_vlan_pcp
291 1
        self.dl_type = dl_type
292 1
        self.nw_proto = nw_proto
293 1
        self.nw_src = nw_src
294 1
        self.nw_dst = nw_dst
295 1
        self.tp_src = tp_src
296 1
        self.tp_dst = tp_dst
297 1
        self.in_phy_port = in_phy_port
298 1
        self.ip_dscp = ip_dscp
299 1
        self.ip_ecn = ip_ecn
300 1
        self.udp_src = udp_src
301 1
        self.udp_dst = udp_dst
302 1
        self.icmpv4_type = icmpv4_type
303 1
        self.icmpv4_code = icmpv4_code
304 1
        self.arp_op = arp_op
305 1
        self.ipv6_flabel = ipv6_flabel
306 1
        self.icmpv6_type = icmpv6_type
307 1
        self.icmpv6_code = icmpv6_code
308 1
        self.nd_tar = nd_tar
309 1
        self.nd_sll = nd_sll
310 1
        self.nd_tll = nd_tll
311 1
        self.pbb_isid = pbb_isid
312 1
        self.v6_hdr = v6_hdr
313
314 1
    def as_dict(self):
315
        """Return a dictionary excluding ``None`` values."""
316 1
        return {k: v for k, v in self.__dict__.items() if v is not None}
317
318 1
    @classmethod
319
    def from_dict(cls, match_dict):
320
        """Return a Match instance from a dictionary."""
321 1
        match = cls()
322 1
        for key, value in match_dict.items():
323 1
            if key in match.__dict__:
324 1
                setattr(match, key, value)
325 1
        return match
326
327 1
    @classmethod
328 1
    @abstractmethod
329
    def from_of_match(cls, of_match):
330
        """Return a Match instance from a pyof Match."""
331
332 1
    @abstractmethod
333
    def as_of_match(self):
334
        """Return a python-openflow Match."""
335
336
337 1
class Stats:
338
    """Simple class to store statistics as attributes and values."""
339
340 1
    def as_dict(self):
341
        """Return a dict excluding attributes with ``None`` value."""
342 1
        return {attribute: value
343
                for attribute, value in vars(self).items()
344
                if value is not None}
345
346 1
    @classmethod
347
    def from_dict(cls, stats_dict):
348
        """Return a statistics object from a dictionary."""
349 1
        stats = cls()
350 1
        cls._update(stats, stats_dict.items())
351 1
        return stats
352
353 1
    @classmethod
354
    def from_of_flow_stats(cls, of_stats):
355
        """Create an instance from a pyof FlowStats."""
356
        stats = cls()
357
        stats.update(of_stats)
358
        return stats
359
360 1
    def update(self, of_stats):
361
        """Given a pyof stats object, update attributes' values.
362
363
        Avoid object creation and memory leak. pyof values are GenericType
364
        instances whose native values can be accessed by `.value`.
365
        """
366
        # Generator for GenericType values
367
        attr_name_value = ((attr_name, gen_type.value)
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368
                           for attr_name, gen_type in vars(of_stats).items()
369
                           if attr_name in vars(self))
370
        self._update(self, attr_name_value)
371
372 1
    @staticmethod
373
    def _update(obj, iterable):
374
        """From attribute name and value pairs, update ``obj``."""
375 1
        for attr_name, value in iterable:
376
            if hasattr(obj, attr_name):
377
                setattr(obj, attr_name, value)
378
379
380 1
class FlowStats(Stats):
381
    """Common fields for 1.0 and 1.3 FlowStats."""
382
383 1
    def __init__(self):
384
        """Initialize all statistics as ``None``."""
385 1
        self.byte_count = None
386 1
        self.duration_sec = None
387 1
        self.duration_nsec = None
388 1
        self.packet_count = None
389
390
391 1
class PortStats(Stats):  # pylint: disable=too-many-instance-attributes
392
    """Common fields for 1.0 and 1.3 PortStats."""
393
394 1
    def __init__(self):
395
        """Initialize all statistics as ``None``."""
396
        self.rx_packets = None
397
        self.tx_packets = None
398
        self.rx_bytes = None
399
        self.tx_bytes = None
400
        self.rx_dropped = None
401
        self.tx_dropped = None
402
        self.rx_errors = None
403
        self.tx_errors = None
404
        self.rx_frame_err = None
405
        self.rx_over_err = None
406
        self.rx_crc_err = None
407
        self.collisions = None
408