Connecting to AWS IoT MQTT topic using Python and Paho MQTT client

pubsub_iot.py

import paho.mqtt.client as paho
import os
import socket
import ssl
from time import sleep
from random import uniform
import json

import logging
logging.basicConfig(level=logging.INFO)

# Refactored original source - https://github.com/mariocannistra/python-paho-mqtt-for-aws-iot

class PubSub(object):

    def __init__(self, listener = False, topic = "default"):
        self.connect = False
        self.listener = listener
        self.topic = topic
        self.logger = logging.getLogger(repr(self))

    def __on_connect(self, client, userdata, flags, rc):
        self.connect = True
        
        if self.listener:
            self.mqttc.subscribe(self.topic)

        self.logger.debug("{0}".format(rc))

    def __on_message(self, client, userdata, msg):
        self.logger.info("{0}, {1} - {2}".format(userdata, msg.topic, msg.payload))

    def __on_log(self, client, userdata, level, buf):
        self.logger.debug("{0}, {1}, {2}, {3}".format(client, userdata, level, buf))

    def bootstrap_mqtt(self):

        self.mqttc = paho.Client()
        self.mqttc.on_connect = self.__on_connect
        self.mqttc.on_message = self.__on_message
        self.mqttc.on_log = self.__on_log

        awshost = "yourthingendpointname.iot.us-east-1.amazonaws.com"
        awsport = 8883

        caPath = "./authority.pem" # Root certificate authority, comes from AWS with a long, long name
        certPath = "./2bafa20887-certificate.pem.crt"
        keyPath = "./2bafa20887-private.pem.key"

        self.mqttc.tls_set(caPath, 
            certfile=certPath, 
            keyfile=keyPath, 
            cert_reqs=ssl.CERT_REQUIRED, 
            tls_version=ssl.PROTOCOL_TLSv1_2, 
            ciphers=None)

        result_of_connection = self.mqttc.connect(awshost, awsport, keepalive=120)

        if result_of_connection == 0:
            self.connect = True

        return self

    def start(self):
        self.mqttc.loop_start()

        while True:
            sleep(2)
            if self.connect == True:
                self.mqttc.publish(self.topic, json.dumps({"message": "Hello COMP680"}), qos=1)
            else:
                self.logger.debug("Attempting to connect.")

if __name__ == '__main__':
    
    PubSub(listener = True, topic = "chat-evets").bootstrap_mqtt().start()

how to create awshost??
capath,certphat and keypath??
help me

You can get the awshost value from your Settings in the AWS IoT Core section of your AWS account. You will need to create a device in AWS IoT Core in order to get the files for certPath and keyPath. During the registration of the device you will also get a link for downloading the caPath file.

I got this working once but now, looking at Wireshark, it seems I am getting a Encrypted Alert and the TLS is being finalized before getting a CONNACK. Any idea how I can fix this?

Late response, but this AWS blog post introduction shows how to setup the required certificates.