Python异步与Node.js异步：如何实现Python异步函数非阻塞执行？

我分别用Node.js和Python asyncio实现了异步脚本：

Node.js实现代码 #

function sleep(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

async function get_burgers() {
  console.log("Just ordered...");
  console.log("Making burgers");
  await sleep(3000);
  console.log("Burgers ready!");
  console.log("Eating them...");
}

async function main() {
  console.log("Walking into restaurant...");
  console.log("Ordering...");
  get_burgers();
  console.log("Talking, talking, talking...");
}

main();

Node.js代码输出 #

Walking into restaurant...
Ordering...
Just ordered...
Making burgers
Talking, talking, talking...
Burgers ready!
Eating them...

Python asyncio初始实现代码 #

import asyncio


async def get_burgers():
    print("Just ordered...")
    print("Making burgers...")
    await asyncio.sleep(5)
    print("Burgers ready!")
    print("Eating burgers")


async def main():
    print("Walking into store with crush")
    print("Ordering....")
    await asyncio.gather(get_burgers())
    print("Talking, talking, talking...")


asyncio.run(main())

当前Python脚本会阻塞后续代码，导致“Talking, talking, talking...”最后打印；若去掉await asyncio.gather前的await则会报错。如何修改Python脚本，使其输出效果与Node.js版本一致？

要实现和Node.js一致的非阻塞效果，只需创建异步任务但不立即等待，让事件循环在执行后续代码的同时后台处理异步任务。修改后的Python代码如下：

import asyncio


async def get_burgers():
    print("Just ordered...")
    print("Making burgers...")
    await asyncio.sleep(5)
    print("Burgers ready!")
    print("Eating burgers")


async def main():
    print("Walking into store with crush")
    print("Ordering....")
    # 创建异步任务提交给事件循环，不阻塞后续代码执行
    asyncio.create_task(get_burgers())
    print("Talking, talking, talking...")


asyncio.run(main())

逻辑说明 #

• Node.js中直接调用get_burgers()会生成一个未被await的Promise，事件循环会在后台处理这个异步任务，同时继续执行后续代码。
• Python里对应的操作是用asyncio.create_task()把协程包装成任务，交给事件循环调度。这样main()函数不会卡在get_burgers()处，会直接执行后续打印语句，而get_burgers()会在后台等待sleep完成后继续执行剩余逻辑。

内容的提问来源于stack exchange，提问作者RogerKint