Async execution

Use submit() for asynchronous single-task execution.

from ttasks import Task, TaskExecutor

with TaskExecutor() as executor:
    task = Task.bash("echo async", title="Async example")
    future = executor.submit(task)
    result = future.result()

assert result.output == "async\n"

submit() runs the same execute() path, so lifecycle events, auto-persistence, progress events, output events, results, and handler errors behave the same way as synchronous execution.

Shutdown

The worker pool is created lazily on the first submit() call.

executor.shutdown()
assert executor.is_shutdown

shutdown() is idempotent, rejects later submit() calls, and waits for already-submitted tasks to finish, including queued tasks that have not started yet. It does not cancel running or queued tasks.

close() is an alias for shutdown(), and the context-manager protocol closes the executor on exit.

Cancellation

Use executor.cancel(task) for cooperative cancellation because future.cancel() can only cancel work that has not started yet.

future = executor.submit(task)
executor.cancel(task)

Graph execution owns graph-level scheduling. The async submit API is a single-task primitive; graph dependencies and finally-task semantics remain on TaskGraph.