forked from platypush/platypush
Fabio Manganiello
201bb5986f
If we open multiple connections from multiple MQTT-based backends to the same host, with some of them having no topics subscribed, Paho-MQTT can mess up which client is supposed to receive which message and we may end up with lost messages on the platypush_bus_mqt/<host> topic.
350 lines
15 KiB
Python
350 lines
15 KiB
Python
import json
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import os
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import threading
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from typing import Optional, List, Callable
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import paho.mqtt.client as mqtt
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from platypush.backend import Backend
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from platypush.config import Config
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from platypush.context import get_plugin
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from platypush.message import Message
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from platypush.message.event.mqtt import MQTTMessageEvent
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from platypush.message.request import Request
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from platypush.plugins.mqtt import MqttPlugin as MQTTPlugin
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from platypush.utils import set_thread_name
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class MqttClient(mqtt.Client, threading.Thread):
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def __init__(self, *args, host: str, port: int, topics: Optional[List[str]] = None,
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on_message: Optional[Callable] = None, username: Optional[str] = None, password: Optional[str] = None,
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client_id: Optional[str] = None, tls_cafile: Optional[str] = None, tls_certfile: Optional[str] = None,
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tls_keyfile: Optional[str] = None, tls_version: Optional = None, tls_ciphers: Optional = None,
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tls_insecure: bool = False, keepalive: Optional[int] = 60, **kwargs):
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mqtt.Client.__init__(self, *args, client_id=client_id, **kwargs)
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threading.Thread.__init__(self)
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self.host = host
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self.port = port
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self.topics = set(topics or [])
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self.keepalive = keepalive
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self.on_connect = self.connect_hndl()
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if on_message:
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self.on_message = on_message
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if username and password:
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self.username_pw_set(username, password)
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if tls_cafile:
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self.tls_set(ca_certs=tls_cafile, certfile=tls_certfile, keyfile=tls_keyfile, tls_version=tls_version,
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ciphers=tls_ciphers)
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self.tls_insecure_set(tls_insecure)
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self._running = False
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self._stop_scheduled = False
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def subscribe(self, *topics, **kwargs):
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if not topics:
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topics = self.topics
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self.topics.update(topics)
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for topic in topics:
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super().subscribe(topic, **kwargs)
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def unsubscribe(self, *topics, **kwargs):
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if not topics:
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topics = self.topics
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for topic in topics:
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super().unsubscribe(topic, **kwargs)
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self.topics.remove(topic)
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def connect_hndl(self):
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def handler(*_, **__):
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self.subscribe()
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return handler
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def run(self):
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super().run()
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self.connect(host=self.host, port=self.port, keepalive=self.keepalive)
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self._running = True
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self.loop_forever()
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def stop(self):
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if not self.is_alive():
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return
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self._stop_scheduled = True
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self.disconnect()
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self._running = False
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class MqttBackend(Backend):
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"""
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Backend that reads messages from a configured MQTT topic (default:
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``platypush_bus_mq/<device_id>``) and posts them to the application bus.
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Triggers:
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* :class:`platypush.message.event.mqtt.MQTTMessageEvent` when a new
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message is received on one of the custom listeners
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Requires:
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* **paho-mqtt** (``pip install paho-mqtt``)
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"""
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_default_mqtt_port = 1883
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def __init__(self, host: Optional[str] = None, port: int = _default_mqtt_port,
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topic='platypush_bus_mq', subscribe_default_topic: bool = True,
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tls_cafile: Optional[str] = None, tls_certfile: Optional[str] = None,
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tls_keyfile: Optional[str] = None, tls_version: Optional[str] = None,
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tls_ciphers: Optional[str] = None, tls_insecure: bool = False,
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username: Optional[str] = None, password: Optional[str] = None,
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client_id: Optional[str] = None, listeners=None,
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*args, **kwargs):
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"""
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:param host: MQTT broker host. If no host configuration is specified then
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the backend will use the host configuration specified on the ``mqtt``
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plugin if it's available.
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:param port: MQTT broker port (default: 1883)
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:param topic: Topic to read messages from (default: ``platypush_bus_mq/<device_id>``)
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:param subscribe_default_topic: Whether the backend should subscribe the default topic (default:
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``platypush_bus_mq/<device_id>``) and execute the messages received there as action requests
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(default: True).
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:param tls_cafile: If TLS/SSL is enabled on the MQTT server and the certificate requires a certificate authority
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to authenticate it, `ssl_cafile` will point to the provided ca.crt file (default: None)
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:param tls_certfile: If TLS/SSL is enabled on the MQTT server and a client certificate it required, specify it
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here (default: None)
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:param tls_keyfile: If TLS/SSL is enabled on the MQTT server and a client certificate key it required,
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specify it here (default: None) :type tls_keyfile: str
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:param tls_version: If TLS/SSL is enabled on the MQTT server and it requires a certain TLS version, specify it
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here (default: None). Supported versions: ``tls`` (automatic), ``tlsv1``, ``tlsv1.1``, ``tlsv1.2``.
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:param tls_ciphers: If TLS/SSL is enabled on the MQTT server and an explicit list of supported ciphers is
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required, specify it here (default: None)
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:param tls_insecure: Set to True to ignore TLS insecure warnings (default: False).
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:param username: Specify it if the MQTT server requires authentication (default: None)
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:param password: Specify it if the MQTT server requires authentication (default: None)
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:param client_id: ID used to identify the client on the MQTT server (default: None).
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If None is specified then ``Config.get('device_id')`` will be used.
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:param listeners: If specified then the MQTT backend will also listen for
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messages on the additional configured message queues. This parameter
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is a list of maps where each item supports the same arguments passed
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to the main backend configuration (host, port, topic, password etc.).
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Note that the message queue configured on the main configuration
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will expect valid Platypush messages that then can execute, while
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message queues registered to the listeners will accept any message. Example::
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listeners:
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- host: localhost
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topics:
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- topic1
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- topic2
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- topic3
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- host: sensors
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topics:
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- topic4
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- topic5
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"""
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super().__init__(*args, **kwargs)
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if host:
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self.host = host
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self.port = port
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self.tls_cafile = self._expandpath(tls_cafile) if tls_cafile else None
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self.tls_certfile = self._expandpath(tls_certfile) if tls_certfile else None
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self.tls_keyfile = self._expandpath(tls_keyfile) if tls_keyfile else None
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self.tls_version = MQTTPlugin.get_tls_version(tls_version)
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self.tls_ciphers = tls_ciphers
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self.tls_insecure = tls_insecure
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self.username = username
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self.password = password
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self.client_id = client_id or Config.get('device_id')
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else:
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client = get_plugin('mqtt')
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assert client.host, 'No host specified on backend.mqtt nor mqtt configuration'
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self.host = client.host
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self.port = client.port
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self.tls_cafile = client.tls_cafile
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self.tls_certfile = client.tls_certfile
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self.tls_keyfile = client.tls_keyfile
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self.tls_version = client.tls_version
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self.tls_ciphers = client.tls_ciphers
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self.tls_insecure = client.tls_insecure
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self.username = client.username
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self.password = client.password
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self.client_id = client_id or client.client_id
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self.topic = '{}/{}'.format(topic, self.device_id)
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self.subscribe_default_topic = subscribe_default_topic
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self._listeners = {} # (host, port, msg_handler) -> MqttClient map
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self.listeners_conf = listeners or []
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def send_message(self, msg, topic: Optional[str] = None, **kwargs):
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try:
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client = get_plugin('mqtt')
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client.send_message(topic=topic or self.topic, msg=msg, host=self.host,
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port=self.port, username=self.username,
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password=self.password, tls_cafile=self.tls_cafile,
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tls_certfile=self.tls_certfile, tls_keyfile=self.tls_keyfile,
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tls_version=self.tls_version, tls_insecure=self.tls_insecure,
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tls_ciphers=self.tls_ciphers, **kwargs)
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except Exception as e:
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self.logger.exception(e)
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@staticmethod
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def _expandpath(path: str) -> str:
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return os.path.abspath(os.path.expanduser(path)) if path else path
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def add_listeners(self, *listeners):
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# noinspection PyShadowingNames,PyUnusedLocal
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for i, listener in enumerate(listeners):
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host = listener.get('host')
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if host:
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port = listener.get('port', self._default_mqtt_port)
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username = listener.get('username')
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password = listener.get('password')
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tls_cafile = self._expandpath(listener.get('tls_cafile'))
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tls_certfile = self._expandpath(listener.get('tls_certfile'))
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tls_keyfile = self._expandpath(listener.get('tls_keyfile'))
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tls_version = MQTTPlugin.get_tls_version(listener.get('tls_version'))
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tls_ciphers = listener.get('tls_ciphers')
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tls_insecure = listener.get('tls_insecure')
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else:
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host = self.host
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port = self.port
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username = self.username
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password = self.password
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tls_cafile = self.tls_cafile
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tls_certfile = self.tls_certfile
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tls_keyfile = self.tls_keyfile
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tls_version = self.tls_version
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tls_ciphers = self.tls_ciphers
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tls_insecure = self.tls_insecure
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topics = listener.get('topics')
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if not topics:
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self.logger.warning('No list of topics specified for listener n.{}'.format(i+1))
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continue
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client = self._get_client(host=host, port=port, topics=topics, username=username, password=password,
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client_id=self.client_id, tls_cafile=tls_cafile, tls_certfile=tls_certfile,
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tls_keyfile=tls_keyfile, tls_version=tls_version, tls_ciphers=tls_ciphers,
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tls_insecure=tls_insecure)
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if not client.is_alive():
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client.start()
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def _get_client(self, host: str, port: int, topics: Optional[List[str]] = None, username: Optional[str] = None,
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password: Optional[str] = None, client_id: Optional[str] = None, tls_cafile: Optional[str] = None,
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tls_certfile: Optional[str] = None, tls_keyfile: Optional[str] = None, tls_version: Optional = None,
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tls_ciphers: Optional = None, tls_insecure: bool = False, on_message: Optional[Callable] = None) \
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-> MqttClient:
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on_message = on_message or self.on_mqtt_message()
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on_message_name = repr(on_message)
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client = self._listeners.get((host, port, on_message_name))
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if not (client and client.is_alive()):
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client = MqttClient(host=host, port=port, topics=topics, username=username, password=password,
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client_id=client_id, tls_cafile=tls_cafile, tls_certfile=tls_certfile,
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tls_keyfile=tls_keyfile, tls_version=tls_version, tls_ciphers=tls_ciphers,
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tls_insecure=tls_insecure, on_message=on_message)
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self._listeners[(host, port, on_message_name)] = client
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client.subscribe(*topics)
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return client
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def on_mqtt_message(self):
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def handler(client, __, msg):
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data = msg.payload
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# noinspection PyBroadException
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try:
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data = data.decode('utf-8')
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data = json.loads(data)
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except:
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pass
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# noinspection PyProtectedMember
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self.bus.post(MQTTMessageEvent(host=client._host, port=client._port, topic=msg.topic, msg=data))
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return handler
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def on_exec_message(self):
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def handler(_, __, msg):
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# noinspection PyShadowingNames
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def response_thread(msg):
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set_thread_name('MQTTProcessor')
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response = self.get_message_response(msg)
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if not response:
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return
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response_topic = '{}/responses/{}'.format(self.topic, msg.id)
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self.logger.info('Processing response on the MQTT topic {}: {}'.
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format(response_topic, response))
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self.send_message(response)
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msg = msg.payload.decode('utf-8')
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# noinspection PyBroadException
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try:
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msg = json.loads(msg)
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msg = Message.build(msg)
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except:
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pass
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if not msg:
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return
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self.logger.info('Received message on the MQTT backend: {}'.format(msg))
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try:
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self.on_message(msg)
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except Exception as e:
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self.logger.exception(e)
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return
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if isinstance(msg, Request):
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threading.Thread(target=response_thread, name='MQTTProcessor', args=(msg,)).start()
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return handler
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def run(self):
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super().run()
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if self.host and self.subscribe_default_topic:
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topics = [self.topic]
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client = self._get_client(host=self.host, port=self.port, topics=topics, username=self.username,
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password=self.password, client_id=self.client_id,
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tls_cafile=self.tls_cafile, tls_certfile=self.tls_certfile,
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tls_keyfile=self.tls_keyfile, tls_version=self.tls_version,
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tls_ciphers=self.tls_ciphers, tls_insecure=self.tls_insecure,
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on_message=self.on_exec_message())
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client.start()
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self.logger.info('Initialized MQTT backend on host {}:{}, topic {}'.
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format(self.host, self.port, self.topic))
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self.add_listeners(*self.listeners_conf)
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def stop(self):
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self.logger.info('Received STOP event on the MQTT backend')
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for ((host, port, _), listener) in self._listeners.items():
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try:
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listener.loop_stop()
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listener.disconnect()
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except Exception as e:
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# noinspection PyProtectedMember
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self.logger.warning('Could not stop listener {host}:{port}: {error}'.
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format(host=host, port=port, error=str(e)))
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# vim:sw=4:ts=4:et:
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