Example of an agent code to publish a message with certain 'topic', 'header', and 'message' to the information exchange bus (IEB)

Publish_Agent_Msg_IEB

# -*- coding: utf-8 -*- {{{
from datetime import datetime
import logging
import sys
from volttron.lite.agent import BaseAgent, PublishMixin, periodic
from volttron.lite.agent import utils, matching
from volttron.lite.messaging import headers as headers_mod

utils.setup_logging()
_log = logging.getLogger(__name__)
hearbeat_period = 5  # in second

class ListenerAgent(PublishMixin, BaseAgent):
    '''Listens to everything and publishes a heartbeat according to the
    heartbeat period specified in the settings module.
    '''

    def __init__(self, config_path, **kwargs):
        super(ListenerAgent, self).__init__(**kwargs)
        self.config = utils.load_config(config_path)

    def setup(self):
        # Demonstrate accessing a value from the config file
        _log.info(self.config['message'])
        self._agent_id = self.config['agentid']
        # Always call the base class setup()
        super(ListenerAgent, self).setup()

    @matching.match_all
    def on_match(self, topic, headers, message, match):
        # Use match_all to receive all messages and print them out.
        _log.debug("Topic: {topic}, Headers: {headers}, "
                    "Message: {message}".format(
                    topic=topic, headers=headers, message=message))

    # Demonstrate periodic decorator and settings access
    @periodic(hearbeat_period)
    def publish_heartbeat(self):
        ''' Send heartbeat message every HEARTBEAT_PERIOD seconds.

        HEARTBEAT_PERIOD is set and can be adjusted '''

        now = datetime.utcnow().isoformat(' ') + 'Z'
        topic = 'ui/agent/bemoss/999/thermostat/1NSTXXXXX/device_status'
        headers = {
            'AgentID': self._agent_id,
            headers_mod.CONTENT_TYPE: headers_mod.CONTENT_TYPE.PLAIN_TEXT,
            headers_mod.DATE: now,
        }
        message = 'Update thermostat data'
        self.publish(topic, headers, message)

def main(argv=sys.argv):
    '''Main method called by the eggsecutable.'''
    try:
        utils.default_main(ListenerAgent,
                           description='Example VOLTTRON platform™ heartbeat agent',
                           argv=argv)
    except Exception as e:
        _log.exception('unhandled exception')


if __name__ == '__main__':
    # Entry point for script
    try:
        sys.exit(main())
    except KeyboardInterrupt:
        pass