The asyncio
library in Python is a powerful tool used to write concurrent code using the async/await syntax. This means it can manage tasks and operations that can run independently of each other, offering a more systematic and efficient execution of tasks.
In Python, concurrent operations could be associated with multiple I/O requests waiting for responses, database operations, web scraping, or any operation which would otherwise cause your program to halt while waiting for a task to complete.
Below is a basic example of how asyncio
is used with the async/await
syntax:
import asyncio
async def task(name, delay):
await asyncio.sleep(delay)
print(f'Task {name} completed')
async def main():
tasks = [task('Task 1', 4), task('Task 2', 2)]
await asyncio.gather(*tasks)
asyncio.run(main())
In this example, asyncio.run(main())
is considered the main entry point for the asyncio program, and the gather
function is used to schedule multiple tasks simultaneously.
Proper Use of Async/Await: In Python, the use of async/await
is reserved for a specific type of function known as a coroutine. Functions with the async
keyword are treated by Python as a coroutine, and can have await
expressions in their body.
Avoid Blocking Functions: Blocking functions halt the execution of the program and can create issues with asyncio's event loop. It's important to replace blocking functions with non-blocking counterparts which are compatible with asyncio.
Handle Exceptions Properly: When using asyncio, make sure to handle exceptions properly. Unhandled exceptions can cause the event loop to stop, terminating your program's execution.
Use High-Level APIs When Possible: Asyncio provides both high and low-level APIs for dealing with concurrency. Whenever possible, use high-level APIs as they are easier to work with and generally safer.
Using the asyncio
library properly can drastically enhance the performance and responsiveness of your Python applications, particularly for I/O-bound and high-level structured network code.