High-level API Index (original) (raw)
This page lists all high-level async/await enabled asyncio APIs.
Tasks¶
Utilities to run asyncio programs, create Tasks, and await on multiple things with timeouts.
| run() | Create event loop, run a coroutine, close the loop. |
|---|---|
| Runner | A context manager that simplifies multiple async function calls. |
| Task | Task object. |
| TaskGroup | A context manager that holds a group of tasks. Provides a convenient and reliable way to wait for all tasks in the group to finish. |
| create_task() | Start an asyncio Task, then returns it. |
| current_task() | Return the current Task. |
| all_tasks() | Return all tasks that are not yet finished for an event loop. |
| await sleep() | Sleep for a number of seconds. |
| await gather() | Schedule and wait for things concurrently. |
| await wait_for() | Run with a timeout. |
| await shield() | Shield from cancellation. |
| await wait() | Monitor for completion. |
| timeout() | Run with a timeout. Useful in cases when wait_for is not suitable. |
| to_thread() | Asynchronously run a function in a separate OS thread. |
| run_coroutine_threadsafe() | Schedule a coroutine from another OS thread. |
| for in as_completed() | Monitor for completion with a for loop. |
Examples
- Using asyncio.gather() to run things in parallel.
- Using asyncio.wait_for() to enforce a timeout.
- Cancellation.
- Using asyncio.sleep().
- See also the main Tasks documentation page.
Queues¶
Queues should be used to distribute work amongst multiple asyncio Tasks, implement connection pools, and pub/sub patterns.
| Queue | A FIFO queue. |
|---|---|
| PriorityQueue | A priority queue. |
| LifoQueue | A LIFO queue. |
Examples
- Using asyncio.Queue to distribute workload between several Tasks.
- See also the Queues documentation page.
Subprocesses¶
Utilities to spawn subprocesses and run shell commands.
| await create_subprocess_exec() | Create a subprocess. |
|---|---|
| await create_subprocess_shell() | Run a shell command. |
Examples
- Executing a shell command.
- See also the subprocess APIsdocumentation.
Streams¶
High-level APIs to work with network IO.
| await open_connection() | Establish a TCP connection. |
|---|---|
| await open_unix_connection() | Establish a Unix socket connection. |
| await start_server() | Start a TCP server. |
| await start_unix_server() | Start a Unix socket server. |
| StreamReader | High-level async/await object to receive network data. |
| StreamWriter | High-level async/await object to send network data. |
Examples
- Example TCP client.
- See also the streams APIsdocumentation.
Synchronization¶
Threading-like synchronization primitives that can be used in Tasks.
| Lock | A mutex lock. |
|---|---|
| Event | An event object. |
| Condition | A condition object. |
| Semaphore | A semaphore. |
| BoundedSemaphore | A bounded semaphore. |
| Barrier | A barrier object. |
Examples
- Using asyncio.Event.
- Using asyncio.Barrier.
- See also the documentation of asynciosynchronization primitives.
Exceptions¶
| asyncio.CancelledError | Raised when a Task is cancelled. See also Task.cancel(). |
|---|---|
| asyncio.BrokenBarrierError | Raised when a Barrier is broken. See also Barrier.wait(). |
Examples
- Handling CancelledError to run code on cancellation request.
- See also the full list ofasyncio-specific exceptions.