async and await in Python

Defining coroutines and awaiting them in an event loop.

import asyncio


async def brew(drink, seconds):
    print(f"brewing {drink}...")
    await asyncio.sleep(seconds)
    return f"{drink} ready"


async def main():
    coffee = await brew("coffee", 0.1)
    tea = await brew("tea", 0.1)
    return [coffee, tea]


drinks = asyncio.run(main())

How it works

1. async def declares a coroutine function.
2. await suspends until the awaited task resolves.
3. asyncio.run(main()) drives the whole thing.

Keywords and builtins used here

• async
• await
• brew
• def
• main
• print
• return

The run, in numbers

Lines

16

Characters to type

266

Tokens

81

Three-star pace

100 tpm

At the three-star pace of 100 tokens a minute, this run takes about 49 seconds.

Type this snippet

Step 1 of 4 in Async, step 24 of 53 in Pythonic Python.

← Previous Next →

async and await in other languages

• JavaScript
• Rust