Using synchronous file operations like open() in asynchronous code blocks the entire event loop. This undermines the primary advantage
of asynchronous programming - the ability to perform concurrent operations without blocking execution.
When an async function makes a synchronous file operation:
- The event loop is completely blocked until the file I/O operation completes
- No other coroutines can run during this time, even if they’re ready to execute
- The responsiveness of the application is degraded
- In server applications, this can cause timeouts or failures for other concurrent requests
Instead, async libraries provide mechanisms to handle file operations asynchronously:
-
aiofiles library for asyncio
-
trio.open_file() for Trio
-
anyio.open_file() for AnyIO
Using these constructs allows other tasks to continue executing while waiting for the potentially blocking file operation to complete.
