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build.flow.ActionFactoryBase.from_dict()   A

Complexity

Conditions 2

Size

Total Lines 10
Code Lines 5

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 4
CRAP Score 2

Importance

Changes 0
Metric Value
cc 2
eloc 5
nop 2
dl 0
loc 10
ccs 4
cts 4
cp 1
crap 2
rs 10
c 0
b 0
f 0
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"""High-level abstraction for Flows of multiple OpenFlow versions.
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Use common fields of FlowStats/FlowMod of supported OF versions. ``match`` and
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``actions`` fields are different, so Flow, Action and Match related classes are
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inherited in v0x01 and v0x04 modules.
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"""
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import json
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from abc import ABC, abstractmethod
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from hashlib import md5
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# Note: FlowModCommand is the same in both v0x01 and v0x04
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from pyof.v0x04.controller2switch.flow_mod import FlowModCommand
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from napps.kytos.of_core import v0x01, v0x04
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class FlowFactory(ABC):  # pylint: disable=too-few-public-methods
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    """Choose the correct Flow according to OpenFlow version."""
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    @classmethod
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    def from_of_flow_stats(cls, of_flow_stats, switch):
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        """Return a Flow for the switch OpenFlow version."""
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        flow_class = cls.get_class(switch)
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        return flow_class.from_of_flow_stats(of_flow_stats, switch)
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    @staticmethod
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    def get_class(switch):
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        """Return the Flow class for the switch OF version."""
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        of_version = switch.connection.protocol.version
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        if of_version == 0x01:
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            return v0x01.flow.Flow
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        if of_version == 0x04:
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            return v0x04.flow.Flow
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        raise NotImplementedError(f'Unsupported OpenFlow version {of_version}')
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class FlowBase(ABC):  # pylint: disable=too-many-instance-attributes
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    """Class to abstract a Flow to switches.
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    This class represents a Flow installed or to be installed inside the
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    switch. A flow, in this case is represented by a Match object and a set of
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    actions that should occur in case any match happen.
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    """
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    # of_version number: 0x01, 0x04
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    of_version = None
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    # Subclasses must set their version-specific classes
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    _action_factory = None
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    _flow_mod_class = None
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    _match_class = None
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    def __init__(self, switch, table_id=0xff, match=None, priority=0x8000,
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                 idle_timeout=0, hard_timeout=0, cookie=0, actions=None,
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                 stats=None):
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        """Assign parameters to attributes.
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        Args:
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            switch (kytos.core.switch.Switch): Switch ID is used to uniquely
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                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.
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            priority (int): Priority level of flow entry.
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            idle_timeout (int): Idle time before discarding, in seconds.
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            hard_timeout (int): Max time before discarding, in seconds.
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            cookie (int): Opaque controller-issued identifier.
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            actions (|list_of_actions|): List of actions to apply.
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            stats (Stats): Latest flow statistics.
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        """
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        # pylint: disable=too-many-arguments,too-many-locals
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        self.switch = switch
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        self.table_id = table_id
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        # Disable not-callable error as subclasses set a class
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        self.match = match or self._match_class()  # pylint: disable=E1102
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        self.priority = priority
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        self.idle_timeout = idle_timeout
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        self.hard_timeout = hard_timeout
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        self.cookie = cookie
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        self.actions = actions or []
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        self.stats = stats or FlowStats()  # pylint: disable=E1102
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    @property
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    def id(self):  # pylint: disable=invalid-name
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        """Return this flow unique identifier.
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        Calculate an md5 hash based on this object's modified json string. The
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        json for ID calculation excludes ``stats`` attribute that changes over
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        time.
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        Returns:
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            str: Flow unique identifier (md5sum).
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        """
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        flow_str = self.as_json(sort_keys=True, include_id=False)
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        md5sum = md5()
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        md5sum.update(flow_str.encode('utf-8'))
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        return md5sum.hexdigest()
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    def as_dict(self, include_id=True):
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        """Return the Flow as a serializable Python dictionary.
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        Args:
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            include_id (bool): Default is ``True``. Internally, it is set to
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                ``False`` when calculating the flow ID that is based in this
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                dictionary's JSON string.
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        Returns:
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            dict: Serializable dictionary.
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        """
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        flow_dict = {
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            'switch': self.switch.id,
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            'table_id': self.table_id,
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            'match': self.match.as_dict(),
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            'priority': self.priority,
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            'idle_timeout': self.idle_timeout,
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            'hard_timeout': self.hard_timeout,
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            'cookie': self.cookie,
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            'actions': [action.as_dict() for action in self.actions]}
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        if include_id:
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            # Avoid infinite recursion
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            flow_dict['id'] = self.id
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            # Remove statistics that change over time
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            flow_dict['stats'] = self.stats.as_dict()
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        return flow_dict
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    @classmethod
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    def from_dict(cls, flow_dict, switch):
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        """Return an instance with values from ``flow_dict``."""
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        flow = cls(switch)
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        # Set attributes found in ``flow_dict``
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        for attr_name, attr_value in flow_dict.items():
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            if attr_name in vars(flow):
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                setattr(flow, attr_name, attr_value)
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        flow.switch = switch
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        if 'stats' in flow_dict:
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            flow.stats = FlowStats.from_dict(flow_dict['stats'])
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        # Version-specific attributes
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        if 'match' in flow_dict:
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            flow.match = cls._match_class.from_dict(flow_dict['match'])
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        if 'actions' in flow_dict:
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            flow.actions = []
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            for action_dict in flow_dict['actions']:
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                action = cls._action_factory.from_dict(action_dict)
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                if action:
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                    flow.actions.append(action)
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        return flow
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    def as_json(self, sort_keys=False, include_id=True):
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        """Return the representation of a flow in JSON format.
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        Args:
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            sort_keys (bool): ``False`` by default (Python's default). Sorting
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                is used, for example, to calculate the flow ID.
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            include_id (bool): ``True`` by default. Internally, the ID is not
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                included while calculating it.
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        Returns:
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            string: Flow JSON string representation.
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        """
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        return json.dumps(self.as_dict(include_id), sort_keys=sort_keys)
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    def as_of_add_flow_mod(self):
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        """Return an OpenFlow add FlowMod."""
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        return self._as_of_flow_mod(FlowModCommand.OFPFC_ADD)
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    def as_of_delete_flow_mod(self):
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        """Return an OpenFlow delete FlowMod."""
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        return self._as_of_flow_mod(FlowModCommand.OFPFC_DELETE)
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    @abstractmethod
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    def _as_of_flow_mod(self, command):
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        """Return a pyof FlowMod with given ``command``."""
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        # Disable not-callable error as subclasses will set a class
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        flow_mod = self._flow_mod_class()  # pylint: disable=E1102
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        flow_mod.match = self.match.as_of_match()
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        flow_mod.cookie = self.cookie
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        flow_mod.command = command
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        flow_mod.idle_timeout = self.idle_timeout
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        flow_mod.hard_timeout = self.hard_timeout
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        flow_mod.priority = self.priority
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        return flow_mod
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    @staticmethod
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    @abstractmethod
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    def _get_of_actions(of_flow_stats):
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        """Return pyof actions from pyof FlowStats."""
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    @classmethod
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    def from_of_flow_stats(cls, of_flow_stats, switch):
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        """Create a flow with latest stats based on pyof FlowStats."""
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        of_actions = cls._get_of_actions(of_flow_stats)
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        actions = (cls._action_factory.from_of_action(of_action)
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                   for of_action in of_actions)
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        non_none_actions = [action for action in actions if action]
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        return cls(switch,
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                   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))
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class ActionBase(ABC):
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    """Base class for a flow action."""
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    def as_dict(self):
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        """Return a dict that can be dumped as JSON."""
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        return vars(self)
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    @classmethod
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    def from_dict(cls, action_dict):
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        """Return an action instance from attributes in a dictionary."""
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        action = cls(None)
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        for attr_name, value in action_dict.items():
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            if hasattr(action, attr_name):
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                setattr(action, attr_name, value)
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        return action
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    @abstractmethod
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    def as_of_action(self):
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        """Return a pyof action to be used by a FlowMod."""
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    @classmethod
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    @abstractmethod
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    def from_of_action(cls, of_action):
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        """Return an action from a pyof action."""
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class ActionFactoryBase(ABC):
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    """Deal with different implementations of ActionBase."""
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    # key: action_type or pyof class, value: ActionBase child
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    _action_class = {
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        'output': None,
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        'set_vlan': None,
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        # pyof class: ActionBase child
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    }
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    @classmethod
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    def from_dict(cls, action_dict):
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        """Build the proper Action from a dictionary.
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        Args:
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            action_dict (dict): Action attributes.
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        """
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        action_type = action_dict.get('action_type')
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        action_class = cls._action_class[action_type]
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        return action_class.from_dict(action_dict) if action_class else None
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    @classmethod
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    def from_of_action(cls, of_action):
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        """Build the proper Action from a pyof action.
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        Args:
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            of_action (pyof action): Action from python-openflow.
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        """
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        of_class = type(of_action)
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        action_class = cls._action_class.get(of_class)
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        return action_class.from_of_action(of_action) if action_class else None
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class MatchBase:  # pylint: disable=too-many-instance-attributes
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    """Base class with common high-level Match fields."""
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    def __init__(self, in_port=None, dl_src=None, dl_dst=None, dl_vlan=None,
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                 dl_vlan_pcp=None, dl_type=None, nw_proto=None, nw_src=None,
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                 nw_dst=None, tp_src=None, tp_dst=None):
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        """Make it possible to set all attributes from the constructor."""
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        # pylint: disable=too-many-arguments
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        self.in_port = in_port
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        self.dl_src = dl_src
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        self.dl_dst = dl_dst
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        self.dl_vlan = dl_vlan
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        self.dl_vlan_pcp = dl_vlan_pcp
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        self.dl_type = dl_type
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        self.nw_proto = nw_proto
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        self.nw_src = nw_src
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        self.nw_dst = nw_dst
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        self.tp_src = tp_src
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        self.tp_dst = tp_dst
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    def as_dict(self):
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        """Return a dictionary excluding ``None`` values."""
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        return {k: v for k, v in self.__dict__.items() if v is not None}
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    @classmethod
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    def from_dict(cls, match_dict):
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        """Return a Match instance from a dictionary."""
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        match = cls()
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        for key, value in match_dict.items():
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            if key in match.__dict__:
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                setattr(match, key, value)
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        return match
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    @classmethod
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    @abstractmethod
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    def from_of_match(cls, of_match):
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        """Return a Match instance from a pyof Match."""
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    @abstractmethod
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    def as_of_match(self):
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        """Return a python-openflow Match."""
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class Stats:
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    """Simple class to store statistics as attributes and values."""
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    def as_dict(self):
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        """Return a dict excluding attributes with ``None`` value."""
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        return {attribute: value
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                for attribute, value in vars(self).items()
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                if value is not None}
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    @classmethod
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    def from_dict(cls, stats_dict):
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        """Return a statistics object from a dictionary."""
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        stats = cls()
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        cls._update(stats, stats_dict.items())
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        return stats
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    @classmethod
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    def from_of_flow_stats(cls, of_stats):
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        """Create an instance from a pyof FlowStats."""
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        stats = cls()
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        stats.update(of_stats)
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        return stats
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    def update(self, of_stats):
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        """Given a pyof stats object, update attributes' values.
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        Avoid object creation and memory leak. pyof values are GenericType
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        instances whose native values can be accessed by `.value`.
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        """
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        # Generator for GenericType values
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        attr_name_value = ((attr_name, gen_type.value)
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                           for attr_name, gen_type in vars(of_stats).items()
347
                           if attr_name in vars(self))
348 1
        self._update(self, attr_name_value)
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    @staticmethod
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    def _update(obj, iterable):
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        """From attribute name and value pairs, update ``obj``."""
353 1
        for attr_name, value in iterable:
354 1
            if hasattr(obj, attr_name):
355 1
                setattr(obj, attr_name, value)
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class FlowStats(Stats):
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    """Common fields for 1.0 and 1.3 FlowStats."""
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    def __init__(self):
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        """Initialize all statistics as ``None``."""
363 1
        self.byte_count = None
364 1
        self.duration_sec = None
365 1
        self.duration_nsec = None
366 1
        self.packet_count = None
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class PortStats(Stats):  # pylint: disable=too-many-instance-attributes
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    """Common fields for 1.0 and 1.3 PortStats."""
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    def __init__(self):
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        """Initialize all statistics as ``None``."""
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        self.rx_packets = None
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        self.tx_packets = None
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        self.rx_bytes = None
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        self.tx_bytes = None
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        self.rx_dropped = None
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        self.tx_dropped = None
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        self.rx_errors = None
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        self.tx_errors = None
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        self.rx_frame_err = None
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        self.rx_over_err = None
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        self.rx_crc_err = None
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        self.collisions = None
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