server/backend/mlmAccess.py

import paho.mqtt.client as mqtt
from dbHelper import MaDbHelper
from pairingHandler import MaPairingHandler
import logging, coloredlogs, os, sys, random, string

coloredlogs.install(level='INFO', fmt='%(asctime)s - [%(levelname)s] %(message)s')

class MlmAccess:
    def __init__(self):
        logging.info("=== MlmAccess ===")

        self._config = self._readConfig()

        self._initDb()
        self._initMqtt()

        self._pairingHanlder = MaPairingHandler(self._mqtt, self._db)

        self._mqtt.loop_forever()

    def _initDb(self):
        logging.info("Initializing Database")
        self._db = MaDbHelper(self._config)
        initUsers = [
            ("backend", self._config["MQTT_BACKEND_PASSWORD"], ["mlmAccess/#"], ["mlmAccess/#"]),
            ("pair-actor", self._config["PAIR_SECRET"], ["mlmAccess/pair/request/actor"], ["mlmAccess/pair/response/actor"])
        ]

        for username, password, publishAclPatterns, subscribeAclPatterns in initUsers:
            if not self._db.addUser(username, password, publishAclPatterns, subscribeAclPatterns):
                self._db.updateUser(username, password, publishAclPatterns, subscribeAclPatterns)

    def _initMqtt(self):
        logging.info("Initializing MQTT")
        self._mqtt = client = mqtt.Client(client_id="backend")
        self._mqtt.username_pw_set("backend", self._config["MQTT_BACKEND_PASSWORD"])

        self._mqtt.on_connect = self._mqttOnConnect
        self._mqtt.on_message = self._mqttOnMessage

        self._mqtt.connect(self._config["MQTT_HOST"], self._config["MQTT_PORT"], 60)

    def _mqttOnConnect(self, client, userdata, flags, rc):
        if rc != 0:
            logging.error(f"Error connecting to MQTT broker: {rc}")
            return

        logging.info("Successfully connected to MQTT broker")

        logging.info("Subscribing to actor subjects:")
        for user in self._db.getAllUsers():
            if user.startswith("actor-"):
                actorSubject = f"mlmAccess/actor/{user.replace('actor-', '')}/status"
                logging.info(f"* {actorSubject}")
                client.subscribe(actorSubject)

        # call hooks of child objects
        self._pairingHanlder._mqttOnConnect(client, userdata, flags, rc)

    def _mqttOnMessage(self, client, userdata, message):
        topic = message.topic
        topic = topic.replace("mlmAccess/", "")
        messageContent = str(message.payload.decode("utf-8"))

        logging.info(f"Message on topic {topic}: {messageContent}")

        if topic.startswith("pair"):
            self._pairingHanlder.handlePairingRequest(topic, messageContent)

    def _readConfig(self):

        configKeyPrefix = "MLMACCESS_"

        requiredConfigKeys = [
            'MYSQL_USER',
            'MYSQL_PASSWORD',
            'MYSQL_DATABASE',
            'PAIR_SECRET'
        ]

        allowedConfigKeys = [
            'MYSQL_HOST', 
            'MYSQL_PORT',
            'MQTT_HOST',
            'MQTT_PORT',
        ]

        backendPassword = ''.join(random.choices(string.ascii_uppercase + string.ascii_lowercase + string.digits, k=20))
        config = {
            "MYSQL_HOST": "mysql",
            "MYSQL_PORT": 4306,
            "MQTT_HOST": "mqtt",
            "MQTT_PORT": 1883,
            "MQTT_BACKEND_PASSWORD": backendPassword
        }

        for configKey in requiredConfigKeys:
            if configKeyPrefix + configKey not in os.environ:
                logging.error(f"Required environment value {configKeyPrefix + configKey} is not set")
                sys.exit(1)
            config[configKey] = os.environ[configKeyPrefix + configKey]

        for configKey in allowedConfigKeys:
            if configKeyPrefix + configKey in os.environ:
                config[configKey] = os.environ[configKeyPrefix + configKey]

        logging.info("CONFIG:")
        for key, value in config.items():
            logging.info("    * {:25}: {}".format(key, value))

        return config

if __name__ == "__main__":
    MlmAccess()