Jason Brownlee's Blog, page 7

Asyncio Task That Cancels Itself

You can develop a task that cancels itself by first getting access to the asyncio.Task instance using asyncio.current_task(), then calling the cancel() method. In this tutorial, you will discover how an asyncio task can cancel itself in Python. Let’s get started. What is Asyncio Task Cancellation? Asyncio tasks can be canceled. This can be achieved […]

Python Asyncio On Raspberry Pi

Python developers on Raspberry Pi can use asynchronous programming via asyncio. MicroPython is the dominant version of Python for Raspberry Pi and it supports the async/await language syntax and a simplified version of the asyncio module (formally called uasyncio). This allows coroutines and cooperative multitasking to be used directly in MicroPython for Raspberry Pi projects. […]

Asyncio Cancel Task Cancellation (Uncancel)

You can cancel a request to cancel a task by developing asyncio tasks that are robust to cancellation. This requires tasks that consume a raised CancelledError on cancellation and reset their own count of cancellation requests. In this tutorial, you will discover how to cancel an asyncio task cancellation (uncancel a task). Let’s get started. […]

Asyncio I/O Libraries

We need third-party libraries for common I/O tasks in asyncio programs. This includes libraries that support async file I/O and standard I/O, as well as libraries that support common web application protocols such as HTTP, FTP, and SMTP. In this tutorial, you will discover the best-of-breed third-party libraries for I/O in asyncio programs. Let’s get […]

Asyncio Cancel Task and Wait

You can develop a helper function to cancel an asyncio task and wait for it to be cancelled. In this tutorial, you will discover how to cancel a task and wait for it to be cancelled. Let’s get started. What is Asyncio Task Cancellation? Asyncio tasks can be canceled. This can be achieved by calling […]

How to Force an Asyncio Task to Cancel

You can force an asyncio task to cancel by repeatedly calling the cancel() in a loop. In this tutorial, you will discover how to force an asyncio task to cancel. Let’s get started. What is Asyncio Task Cancellation? Asyncio tasks can be canceled. This can be achieved by calling the cancel() method on the asyncio.Task. […]

Asyncio Helper Libraries

We can use third-party Python libraries to help solve common problems and introduce new capabilities in asyncio programs. Three popular third-party helper asyncio libraries include asyncstdlib, aiomisc, and aiotools. Each provides different capabilities that may be helpful such as wrapping standard functions in the Python standard library to be awaitables, offering function decorators for running […]

Asyncio Task Cancellation Best Practices

Last Updated on December 20, 2023 Tasks in asyncio can be canceled manually and automatically. Therefore, we must develop asyncio programs with the expectation that our custom tasks may be canceled at any time. This requires a certain level of robustness. Thankfully there are common task cancellation idioms and best practices that we can use […]

Python Async Keywords

Python asyncio introduced new async keywords to the language to support coroutines. This includes async expressions such as “async def“, “async for“, and “async with“, as well as the “await” expression. Together, these expressions are referred to as the “async/await” syntax. In this tutorial, you will discover how to use the new expressions and keywords […]

When Are Asyncio Tasks Canceled

Last Updated on December 18, 2023 Asyncio tasks can be canceled at any time. Asyncio tasks can be canceled manually while they are scheduled or running. Additionally, tasks can be automatically canceled by the asyncio infrastructure, such as after a timeout, after a deadline, when one task in the group fails, and, by the event […]