python runtime_error ai_generated true

RuntimeError: asyncio.run() cannot be called from a running event loop

ID: python/asyncio-run-called-from-running-loop

Also available as: JSON · Markdown · 中文
80%Fix Rate
90%Confidence
0Evidence
2024-01-25First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.8 active — — —
3.9 active — — —
3.10 active — — —
3.11 active — — —
3.12 active — — —

Root Cause

asyncio.run() is invoked from inside an already-running event loop, e.g. calling it in a Jupyter notebook cell or from within an async function.

generic

中文

在已运行的事件循环内部调用 asyncio.run()，例如在 Jupyter 笔记本单元格中或异步函数内部调用。

Workarounds

  1. 95% success 
    # in a Jupyter cell
result = await main()  # top-level await, no asyncio.run
  2. 85% success 
    import threading, asyncio
result = {}
def _run():
    result['v'] = asyncio.run(main())
t = threading.Thread(target=_run); t.start(); t.join()

Dead Ends

Common approaches that don't work:

  1. 90% fail

    Raises the same error because the loop is already running.

  2. 70% fail

    Works only if you create a fresh loop in that thread; otherwise you get 'no running event loop'.