a2a.server.tasks.task_manager module

class a2a.server.tasks.task_manager.TaskManager(task_store: TaskStore, context: ServerCallContext, task_id: str | None, context_id: str | None, initial_message: Message | None)

Bases: object

Helps manage a task’s lifecycle during execution of a request.

Responsible for retrieving, saving, and updating the Task object based on events received from the agent.

async ensure_task(event: TaskStatusUpdateEvent | TaskArtifactUpdateEvent) → Task

Ensures a Task object exists in memory, loading from store or creating new if needed.

Parameters:

event – The task-related event triggering the need for a Task object.

Returns:

An existing or newly created Task object.

async ensure_task_id(task_id: str, context_id: str) → Task

Ensures a Task object exists in memory, loading from store or creating new if needed.

Parameters:

  • task_id – The ID for the new task.

  • context_id – The context ID for the new task.

Returns:

An existing or newly created Task object.

async get_task() → Task | None

Retrieves the current task object, either from memory or the store.

If task_id is set, it first checks the in-memory _current_task, then attempts to load it from the task_store.

Returns:

The Task object if found, otherwise None.

async process(event: Message | Task | TaskStatusUpdateEvent | TaskArtifactUpdateEvent) → Message | Task | TaskStatusUpdateEvent | TaskArtifactUpdateEvent

Processes an event, updates the task state if applicable, stores it, and returns the event.

If the event is task-related (Task, TaskStatusUpdateEvent, TaskArtifactUpdateEvent), the internal task state is updated and persisted.

Parameters:

event – The event object received from the agent.

Returns:

The same event object that was processed.

async save_task_event(event: Task | TaskStatusUpdateEvent | TaskArtifactUpdateEvent) → Task | None

Processes a task-related event (Task, Status, Artifact) and saves the updated task state.

Ensures task and context IDs match or are set from the event.

Parameters:

event – The task-related event (Task, TaskStatusUpdateEvent, or TaskArtifactUpdateEvent).

Returns:

The updated Task object after processing the event.

Raises:

InvalidParamsError – If the task ID in the event conflicts with the TaskManager’s ID when the TaskManager’s ID is already set.

update_with_message(message: Message, task: Task) → Task

Updates a task object in memory by adding a new message to its history.

If the task has a message in its current status, that message is moved to the history first.

Parameters:

  • message – The new Message to add to the history.

  • task – The Task object to update.

Returns:

The updated Task object (updated in-place).

a2a.server.tasks.task_manager.append_artifact_to_task(task: Task, event: TaskArtifactUpdateEvent) → None

Helper method for updating a Task object with new artifact data from an event.

Handles creating the artifacts list if it doesn’t exist, adding new artifacts, and appending parts to existing artifacts based on the append flag in the event.

Parameters:

  • task – The Task object to modify.

  • event – The TaskArtifactUpdateEvent containing the artifact data.