Skip to content

Communication

gradysim.simulator.handler.communication.CommunicationHandler

Bases: INodeHandler

Adds communication to the simulation. Nodes, through their providers, can send this handler communication commands that dictate how a message should be sent. This message will be delivered to the destination node.

Messages are transmited through a medium that determines conditions like communication range and failure rate. Messages can fail to be delivered or be delivered late.

Source code in gradysim/simulator/handler/communication.py 
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
class CommunicationHandler(INodeHandler):
    """
    Adds communication to the simulation. Nodes, through their providers, can
    send this handler communication commands that dictate how a message should
    be sent. This message will be delivered to the destination node.

    Messages are transmited through a [medium][gradysim.simulator.handler.communication.CommunicationMedium] that
    determines conditions like communication range and failure rate. Messages can fail to be delivered or 
    be delivered late.
    """
    @staticmethod
    def get_label() -> str:
        return "communication"

    _sources: Dict[int, CommunicationSource]
    _destinations: Dict[int, CommunicationDestination]
    _event_loop: EventLoop

    def __init__(self, communication_medium: CommunicationMedium = CommunicationMedium()):
        """
        Initializes the communication handler.

        Args:
            communication_medium: Configuration of the network conditions. If not set all default values will be used.
        """
        self._injected = False

        self._sources = {}
        self._destinations = {}
        self.communication_medium = communication_medium

    def inject(self, event_loop: EventLoop):
        self._injected = True
        self._event_loop = event_loop

    def register_node(self, node: Node):
        if not self._injected:
            raise CommunicationException("Error registering node: Cannot register node on uninitialized "
                                         "node handler")
        self._sources[node.id] = CommunicationSource(node)
        self._destinations[node.id] = CommunicationDestination(node)

    def handle_command(self, command: CommunicationCommand, sender: Node):
        """
        Performs a communication command. This method should be called by the node's
        provider to transmit a communication command to the communication handler.

        Args:
            command: Command being issued
            sender: Node issuing the command
        """
        if sender.id == command.destination:
            raise CommunicationException("Error transmitting message: message destination is equal to sender. Try "
                                         "using schedule_timer.")

        source = self._sources[sender.id]

        if command.command_type == CommunicationCommandType.BROADCAST:
            for destination, endpoint in self._destinations.items():
                if destination != sender.id:
                    self._transmit_message(command.message, source, endpoint)
        else:
            destination = command.destination
            if destination is None:
                raise CommunicationException("Error transmitting message: a destination is "
                                             "required when command type SEND is used.")
            if destination not in self._destinations:
                raise CommunicationException(f"Error transmitting message: destination {destination} does not exist.")

            self._transmit_message(command.message, source, self._destinations[destination])

    def _transmit_message(self, message: str, source: CommunicationSource, destination: CommunicationDestination):
        source.hand_over_message(message, destination)

        if can_transmit(source.node.position, destination.node.position, self.communication_medium):
            if self.communication_medium.delay <= 0:
                self._event_loop.schedule_event(
                    self._event_loop.current_time,
                    lambda: destination.receive_message(message, source),
                    label_node(destination.node) + " handle_packet"
                )
            else:
                self._event_loop.schedule_event(
                    self._event_loop.current_time + self.communication_medium.delay,
                    lambda: destination.receive_message(message, source),
                    label_node(destination.node) + " handle_packet"
                )

__init__(communication_medium=CommunicationMedium())

Initializes the communication handler.

Parameters:

Name Type Description Default
communication_medium CommunicationMedium

Configuration of the network conditions. If not set all default values will be used.

 CommunicationMedium()
Source code in gradysim/simulator/handler/communication.py 
120
121
122
123
124
125
126
127
128
129
130
131
def __init__(self, communication_medium: CommunicationMedium = CommunicationMedium()):
    """
    Initializes the communication handler.

    Args:
        communication_medium: Configuration of the network conditions. If not set all default values will be used.
    """
    self._injected = False

    self._sources = {}
    self._destinations = {}
    self.communication_medium = communication_medium

handle_command(command, sender)

Performs a communication command. This method should be called by the node's provider to transmit a communication command to the communication handler.

Parameters:

Name Type Description Default
command CommunicationCommand

Command being issued

 required
sender Node

Node issuing the command

 required
Source code in gradysim/simulator/handler/communication.py 
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
def handle_command(self, command: CommunicationCommand, sender: Node):
    """
    Performs a communication command. This method should be called by the node's
    provider to transmit a communication command to the communication handler.

    Args:
        command: Command being issued
        sender: Node issuing the command
    """
    if sender.id == command.destination:
        raise CommunicationException("Error transmitting message: message destination is equal to sender. Try "
                                     "using schedule_timer.")

    source = self._sources[sender.id]

    if command.command_type == CommunicationCommandType.BROADCAST:
        for destination, endpoint in self._destinations.items():
            if destination != sender.id:
                self._transmit_message(command.message, source, endpoint)
    else:
        destination = command.destination
        if destination is None:
            raise CommunicationException("Error transmitting message: a destination is "
                                         "required when command type SEND is used.")
        if destination not in self._destinations:
            raise CommunicationException(f"Error transmitting message: destination {destination} does not exist.")

        self._transmit_message(command.message, source, self._destinations[destination])

gradysim.simulator.handler.communication.CommunicationMedium dataclass

Conditions through which the messages are delivered. Can influence how and when messages can be delivered.

Source code in gradysim/simulator/handler/communication.py 
75
76
77
78
79
80
81
82
83
84
85
86
87
@dataclass
class CommunicationMedium:
    """
    Conditions through which the messages are delivered. Can influence how and when messages can be delivered.
    """
    transmission_range: float = 60
    """Maximum range in meters for message delivery. Messages destined to nodes outside this range will not be delivered"""

    delay: float = 0
    """Sets a delay in seconds for message delivery, representing network delay. Range is evaluated before the delay is applied"""

    failure_rate: float = 0
    """Failure chance between 0 and 1 for message delivery. 0 represents messages never failing and 1 always fails."""

delay: float = 0 class-attribute instance-attribute

Sets a delay in seconds for message delivery, representing network delay. Range is evaluated before the delay is applied

failure_rate: float = 0 class-attribute instance-attribute

Failure chance between 0 and 1 for message delivery. 0 represents messages never failing and 1 always fails.

transmission_range: float = 60 class-attribute instance-attribute

Maximum range in meters for message delivery. Messages destined to nodes outside this range will not be delivered