amqtt/docs/custom_plugins.md

Custom Plugins

With the aMQTT Broker plugins framework, one can add additional functionality to the broker without having to subclass or rewrite any of the core broker logic. To define a custom list of plugins to be loaded, add this section to your pyproject.toml"

[project.entry-points."mypackage.mymodule.plugins"]
plugin_alias = "module.submodule.file:ClassName"

and specify the namespace when instantiating the broker:

from amqtt.broker import Broker

broker = Broker(plugin_namespace='mypackage.mymodule.plugins')

Each plugin has access to the full configuration file through the provided BaseContext and can define its own variables to configure its behavior.

::: amqtt.plugins.base.BasePlugin

Events

Plugins that are defined in theproject.entry-points are notified of events if the subclass implements one or more of these methods:

• async def on_mqtt_packet_sent(self, *, packet: MQTTPacket[MQTTVariableHeader, MQTTPayload[MQTTVariableHeader], MQTTFixedHeader], session: Session | None = None) -> None

• async def on_mqtt_packet_received(self, *, packet: MQTTPacket[MQTTVariableHeader, MQTTPayload[MQTTVariableHeader], MQTTFixedHeader], session: Session | None = None) -> None

• async def on_broker_pre_start(self) -> None

• async def on_broker_post_start(self) -> None

• async def on_broker_pre_shutdown(self) -> None

• async def on_broker_post_shutdown(self) -> None

• async def on_broker_client_connected(self, client_id:str, client_session:Session) -> None

• async def on_broker_client_disconnected(self, client_id:str, client_session:Session) -> None

• async def on_broker_client_connected(self, *, client_id:str) -> None

• async def on_broker_client_disconnected(self, *, client_id:str) -> None

• async def on_broker_client_subscribed(self, *, client_id: str, topic: str, qos: int) -> None

• async def on_broker_client_unsubscribed(self, *, client_id: str, topic: str) -> None

• async def on_broker_message_received(self, *, client_id: str, message: ApplicationMessage) -> None

Authentication Plugins

Of the plugins listed in project.entry-points, one or more can be used to validate client sessions by specifying their alias in auth > plugins section of the config:

auth:
  plugins:
    - plugin_alias_name

These plugins should subclass from BaseAuthPlugin and implement the authenticate method.

::: amqtt.plugins.base.BaseAuthPlugin

Topic Filter Plugins

Of the plugins listed in project.entry-points, one or more can be used to determine topic access by specifying their alias in topic-check > plugins section of the config:

topic-check:
  enable: True
  plugins:
    - plugin_alias_name

These plugins should subclass from BaseTopicPlugin and implement the topic_filtering method.

::: amqtt.plugins.base.BaseTopicPlugin