“RuntimeError: This event loop is already running”; debugging aiohttp, asyncio and IDE “spyder3” in python 3.6.5

Problem Description

https://stackoverflow.com/questions/50243393/runtimeerror-this-event-loop-is-already-running-debugging-aiohttp-asyncio-a From the above link I’m struggling to understand why I am getting the “RuntimeError: This event loop is already running” runtime error. I have tried to run snippets of code from “https://aiohttp.readthedocs.io/en/stable/” however, I keep getting the same issue.

What steps reproduce the problem?

1. Run the following code in Spyder IDE

---

import aiohttp
import asyncio
import time

urls = ['https://api.robinhood.com/quotes/c4f6720a-0364-4e7b-8c41-705696759e1a/']

async def fetch(client, url):
    async with client.request('get', url) as response:
        if response.status == 200:
            data = await response.text()
        else:
            data = []
        print(data)
        return(data)

async def get_async_urls(urls):
    async with aiohttp.ClientSession() as client:
        return await asyncio.gather(*(fetch(client, url) for url in urls))

if __name__ == '__main__':
    t0 = time.time()
    loop = asyncio.get_event_loop()
    results = loop.run_until_complete(get_async_urls(urls))
    print(results)
    t1 = time.time()
    total_time = t1-t0
    loop.close()

---

Results: RuntimeError: This event loop is already running {“ask_price”:“14.9000”,“ask_size”:100,“bid_price”:“14.0100”,“bid_size”:100,“last_trade_price”:“14.7900”,“last_extended_hours_trade_price”:“14.7900”,“previous_close”:“14.3600”,“adjusted_previous_close”:“14.3600”,“previous_close_date”:“2018-05-07”,“symbol”:“SURF”,“trading_halted”:false,“has_traded”:true,“last_trade_price_source”:“consolidated”,“updated_at”:“2018-05-08T20:01:21Z”,“instrument”:“https://api.robinhood.com/instruments/43d56335-f2f6-4711-b650-55be2396f814/”} Expected Results: {“ask_price”:“14.9000”,“ask_size”:100,“bid_price”:“14.0100”,“bid_size”:100,“last_trade_price”:“14.7900”,“last_extended_hours_trade_price”:“14.7900”,“previous_close”:“14.3600”,“adjusted_previous_close”:“14.3600”,“previous_close_date”:“2018-05-07”,“symbol”:“SURF”,“trading_halted”:false,“has_traded”:true,“last_trade_price_source”:“consolidated”,“updated_at”:“2018-05-08T20:01:21Z”,“instrument”:“https://api.robinhood.com/instruments/43d56335-f2f6-4711-b650-55be2396f814/”} [‘{“ask_price”:“14.9000”,“ask_size”:100,“bid_price”:“14.0100”,“bid_size”:100,“last_trade_price”:“14.7900”,“last_extended_hours_trade_price”:“14.7900”,“previous_close”:“14.3600”,“adjusted_previous_close”:“14.3600”,“previous_close_date”:“2018-05-07”,“symbol”:“SURF”,“trading_halted”:false,“has_traded”:true,“last_trade_price_source”:“consolidated”,“updated_at”:“2018-05-08T20:01:21Z”,“instrument”:“https://api.robinhood.com/instruments/43d56335-f2f6-4711-b650-55be2396f814/”}’]

2. Run the code from above with cmd.exe

Results: {“ask_price”:“14.9000”,“ask_size”:100,“bid_price”:“14.0100”,“bid_size”:100,“last_trade_price”:“14.7900”,“last_extended_hours_trade_price”:“14.7900”,“previous_close”:“14.3600”,“adjusted_previous_close”:“14.3600”,“previous_close_date”:“2018-05-07”,“symbol”:“SURF”,“trading_halted”:false,“has_traded”:true,“last_trade_price_source”:“consolidated”,“updated_at”:“2018-05-08T20:01:21Z”,“instrument”:“https://api.robinhood.com/instruments/43d56335-f2f6-4711-b650-55be2396f814/”} [‘{“ask_price”:“14.9000”,“ask_size”:100,“bid_price”:“14.0100”,“bid_size”:100,“last_trade_price”:“14.7900”,“last_extended_hours_trade_price”:“14.7900”,“previous_close”:“14.3600”,“adjusted_previous_close”:“14.3600”,“previous_close_date”:“2018-05-07”,“symbol”:“SURF”,“trading_halted”:false,“has_traded”:true,“last_trade_price_source”:“consolidated”,“updated_at”:“2018-05-08T20:01:21Z”,“instrument”:“https://api.robinhood.com/instruments/43d56335-f2f6-4711-b650-55be2396f814/”}’]

3. The above results match what I expect.

What is the expected output? What do you see instead?

Expected Results: {“ask_price”:“14.9000”,“ask_size”:100,“bid_price”:“14.0100”,“bid_size”:100,“last_trade_price”:“14.7900”,“last_extended_hours_trade_price”:“14.7900”,“previous_close”:“14.3600”,“adjusted_previous_close”:“14.3600”,“previous_close_date”:“2018-05-07”,“symbol”:“SURF”,“trading_halted”:false,“has_traded”:true,“last_trade_price_source”:“consolidated”,“updated_at”:“2018-05-08T20:01:21Z”,“instrument”:“https://api.robinhood.com/instruments/43d56335-f2f6-4711-b650-55be2396f814/”} [‘{“ask_price”:“14.9000”,“ask_size”:100,“bid_price”:“14.0100”,“bid_size”:100,“last_trade_price”:“14.7900”,“last_extended_hours_trade_price”:“14.7900”,“previous_close”:“14.3600”,“adjusted_previous_close”:“14.3600”,“previous_close_date”:“2018-05-07”,“symbol”:“SURF”,“trading_halted”:false,“has_traded”:true,“last_trade_price_source”:“consolidated”,“updated_at”:“2018-05-08T20:01:21Z”,“instrument”:“https://api.robinhood.com/instruments/43d56335-f2f6-4711-b650-55be2396f814/”}’] Results: RuntimeError: This event loop is already running {“ask_price”:“14.9000”,“ask_size”:100,“bid_price”:“14.0100”,“bid_size”:100,“last_trade_price”:“14.7900”,“last_extended_hours_trade_price”:“14.7900”,“previous_close”:“14.3600”,“adjusted_previous_close”:“14.3600”,“previous_close_date”:“2018-05-07”,“symbol”:“SURF”,“trading_halted”:false,“has_traded”:true,“last_trade_price_source”:“consolidated”,“updated_at”:“2018-05-08T20:01:21Z”,“instrument”:“https://api.robinhood.com/instruments/43d56335-f2f6-4711-b650-55be2396f814/”}

Paste Traceback/Error Below (if applicable)

runfile('C:/Playground/Github/tradey/app/test_fast_web_00002.py', wdir='C:/Playground/Github/tradey/app')
Traceback (most recent call last):

  File "<ipython-input-2-437c9e79feb0>", line 1, in <module>
    runfile('C:/Playground/Github/tradey/app/test_fast_web_00002.py', wdir='C:/Playground/Github/tradey/app')

  File "c:\playground\python\python36-32\lib\site-packages\spyder\utils\site\sitecustomize.py", line 705, in runfile
    execfile(filename, namespace)

  File "c:\playground\python\python36-32\lib\site-packages\spyder\utils\site\sitecustomize.py", line 102, in execfile
    exec(compile(f.read(), filename, 'exec'), namespace)

  File "C:/Playground/Github/tradey/app/test_fast_web_00002.py", line 23, in <module>
    loop.run_until_complete(main())

  File "c:\playground\python\python36-32\lib\asyncio\base_events.py", line 455, in run_until_complete
    self.run_forever()

  File "c:\playground\python\python36-32\lib\asyncio\base_events.py", line 409, in run_forever
    raise RuntimeError('This event loop is already running')

RuntimeError: This event loop is already running

Versions

• Spyder version: 3.2.8
• Python version: 3.6.5
• Qt version: 5.9.3
• PyQt version: 5.9.2
• Operating System name/version: Windows

# Dependencies

IPython >=4.0    :  6.3.1 (OK)
cython >=0.21    :  0.28.2 (OK)
jedi >=0.9.0     :  0.12.0 (OK)
nbconvert >=4.0  :  5.3.1 (OK)
numpy >=1.7      :  1.14.2 (OK)
pandas >=0.13.1  :  0.22.0 (OK)
pycodestyle >=2.3:  2.4.0 (OK)
pyflakes >=0.6.0 :  1.6.0 (OK)
pygments >=2.0   :  2.2.0 (OK)
pylint >=0.25    :  1.8.4 (OK)
qtconsole >=4.2.0:  4.3.1 (OK)
rope >=0.9.4     :  0.10.7 (OK)
sphinx >=0.6.6   :  1.7.2 (OK)
sympy >=0.7.3    :  1.1.1 (OK)

[RajshekarReddy]

I got the issue resolved by using the nest_async

pip install nest_asyncio

and adding below lines in my file.

import nest_asyncio
nest_asyncio.apply()

[baumga34]

The solution is to not use spyder. The code works in pycharm, which is what I’ve switched to.

On Thu, Aug 1, 2019, 4:59 AM EEflow [e-mail] wrote:

Is that considered a permanent solution or a quick fix?

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