python-banyan 3.12

A Non-Blocking Event Driven Applications Framework

The Python Banyan Framework

The Python Banyan Framework is a lightweight, reactive framework used to create flexible, non-blocking, event driven, asynchronous applications.

Python Banyan comes with full documentation that includes a User's Guide with hands-on examples, as well documentation for the OneGPIO Project that allows you to quickly and easily build reusable GPIO projects for the Arduino, ESP-8266, and Raspberry Pi.

It is being used by Palace Games to concurrently monitor hundreds of real-time sensors and actuators.

• Based on a network connected Publish/Subscribe model, Banyan components publish user defined protocol messages in the form of Python dictionaries.
• A Banyan protocol message may contain Numpy data.
• Applications may reside on a single computer or be distributed across multiple computers without having to change source code.
• Compatible Banyan Frameworks are available for JavaScript, Ruby, and Java. Components written in any of these languages can interact with components of a differing language without modification.
• Runs on Python 2 or Python 3 (recommended).

To install, view the full installation instructions.

A Simple Banyan Echo Server:

import sys
from python_banyan.banyan_base import BanyanBase


class EchoServer(BanyanBase):
    """
    This class is a simple Banyan echo server
    """
    def __init__(self, ):

        # initialize the parent
        super(EchoServer, self).__init__(process_name='EchoServer')

        # subscribe to receive 'echo' messages from the client
        self.set_subscriber_topic('echo')

        # wait for messages to arrive
        try:
            self.receive_loop()
        except KeyboardInterrupt:
            self.clean_up()
            sys.exit(0)

    def incoming_message_processing(self, topic, payload):
        """
        Process incoming messages from the client
        :param topic: message topic
        :param payload: message payload
        """
        # republish the message with a topic of reply
        self.publish_payload(payload, 'reply')
        
        # extract the message number from the payload
        print('Message number:', payload['message_number'])

A Simple Banyan Echo Client:

import sys
from python_banyan.banyan_base import BanyanBase


class EchoClient(BanyanBase):
    """
    This is a simple echo client derived from the BanyanBase class. 
    It sends out a series of messages and expects an
    echo reply from the server.
    """

    def __init__(self):

        # initialize the parent
        super(EchoClient, self).__init__(process_name='EchoClient')

        # accept banyan messages with the topic of reply
        self.set_subscriber_topic('reply')

        # sequence number of messages and total number of messages to send
        self.message_number = self.number_of_messages = 10

        # send the first message - make sure that the server is already started
        self.publish_payload({'message_number': self.message_number}, 'echo')

        # get the reply messages
        try:
            self.receive_loop()
        except KeyboardInterrupt:
            self.clean_up()
            sys.exit(0)

    def incoming_message_processing(self, topic, payload):
        """
        Process incoming messages received from the echo client
        :param topic: Message Topic string
        :param payload: Message Data
        """

        # When a message is received and its number is zero, finish up.
        if payload['message_number'] == 0:
            print(str(self.number_of_messages) + ' messages sent and received. ')
            input('Press enter to exit.')
            self.clean_up()
            sys.exit(0)
        # bump the message number and send the message out
        else:
            self.message_number -= 1
            if self.message_number >= 0:
                self.publish_payload({'message_number': self.message_number}, 'echo')