nvflare.fuel.data_event.data_bus module

class DataBus

Bases: EventPubSub

Singleton class for a simple data bus implementation.

This class allows components to subscribe to topics, publish messages to topics, and store/retrieve messages associated with specific keys and topics.

Create a new instance of the DataBus class. This method ensures that only one instance of the class is created (singleton pattern). The databus

get_data(key: Any) → Any

Retrieve a stored data associated with a key and topic.

Parameters:

key (Any) – The key associated with the stored message.

Returns:

The stored datum if found, or None if not found.

Return type:

Any

publish(topics: List[str], datum: Any) → None

Publish a data to one or more topics, notifying all subscribed callbacks.

Parameters:

• topics (List[str]) – A list of topics to publish the data to.

• datum (Any) – The data to be published to the specified topics.

put_data(key: Any, datum: Any) → None

Store a data associated with a key and topic.

Parameters:

• key (Any) – The key to associate with the stored message.

• datum (Any) – The message to be stored.

subscribe(topics: List[str], callback: Callable[[str, Any, DataBus], None], **cb_kwargs) → None

Subscribe a callback function to one or more topics.

Parameters:

• topics (List[str]) – A list of topics to subscribe to.

• callback (Callable) – The callback function to be called when messages are published to the subscribed topics.

unsubscribe(topic: str, callback=None) → None

Unsubscribe from the specified topic. If the callback is specified, only remove the subscription that has this callback; If the callback is not specified, remove all subscriptions of this topic.

Parameters:

• topic – the topic to unsubscribe

• callback – the callback to be removed

Returns: None