async timeouts in Python

Bounding how long an await is allowed to take.

import asyncio


async def slow_query():
    await asyncio.sleep(10)
    return "rows"


async def main():
    try:
        return await asyncio.wait_for(slow_query(), timeout=0.2)
    except TimeoutError:
        return "gave up"


outcome = asyncio.run(main())

How it works

1. wait_for cancels the coroutine after timeout.
2. A TimeoutError signals it ran too long.
3. The handler returns a fallback instead.

Keywords and builtins used here

• async
• await
• def
• except
• main
• return
• slow_query
• try

The run, in numbers

Lines

16

Characters to type

230

Tokens

58

Three-star pace

105 tpm

At the three-star pace of 105 tokens a minute, this run takes about 33 seconds.

Type this snippet

Step 3 of 4 in Async, step 26 of 53 in Pythonic Python.

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