Message exchange

Receiving messages

Custom agents that inherit from the Agent class are able to receive messages from other agents via the method handle_message. Hence this method has to be overwritten. The structure of this method looks like this:

def handle_message(self, content, meta: Dict[str, Any]):

    raise NotImplementedError

Once a message arrives at a container, the container is responsible to deserialize the message and to split the content from all meta information. While the meta information may include e. g. information about the sender of the message or about the performative, the content parameter holds the actual content of the message.

A simple agent, that just prints the content and meta information of incoming messages could look like this:

from mango import Agent

class SimpleReceivingAgent(Agent):
    def __init__(self, container):

    def handle_message(self, content, meta):
        print(f'{self.aid} received a message with content {content} and'
            f'meta {meta}')

Sending messages

Agents are able to send messages to other agents via the container method send_message:

async def send_message(self, content,
                        receiver_addr: Union[str, Tuple[str, int]], *,
                        receiver_id: Optional[str] = None,
                        **kwargs) -> bool:

To send a tcp message, the receiver address and receiver id (the agent id of the receiving agent) has to be provided. content defines the content of the message. This will appear as the content argument at the receivers handle_message() method.

If you want to send an ACL-message use the method container.send_acl_message, which will wrap the content in a ACLMessage using create_acl internally.

async def send_acl_message(self, content,
                        receiver_addr: Union[str, Tuple[str, int]], *,
                        receiver_id: Optional[str] = None,
                        acl_metadata: Optional[Dict[str, Any]] = None,
                        **kwargs) -> bool:

The argument acl_metadata enables to set all meta information of an acl message. It expects a dictionary with the field name as string as a key and the field value as key. For example:

from mango.messages.message import Performatives

example_acl_metadata = {
    'performative': Performatives.inform,
    'sender_id': 'agent0',
    'sender_addr': ('localhost', 5555),
    'conversation_id': 'conversation01'

The argument kwargs can be used to set specific configs, if the container is connected via MQTT to a message broker.