python - RuntimeWarning: coroutine 'main' was never awaited

Question

I'm trying to parse and put JSON async but getting:

RuntimeWarning: coroutine 'main' was never awaited

import asyncio
import aiohttp

async def get_put_content(url_get, url_put, session):
    async with session.get(url_get) as response:
        data = await response.read()

    async with session.put(url_put, data=data) as response:
        print(response.status)     

async def main():
    async with aiohttp.ClientSession() as session:
        for temp_id in range (1, 100):
            api_url = "https://api.link" + str(temp_id)
            bd_url = "http://127.0.0.1:5984/photosget/" + str(temp_id)
            asyncio.create_task(get_put_content(api_url, bd_url, session))

        asyncio.wait(get_put_content)

if __name__ == '__main__':
    main()

How I could use async correctly?

Answer 1

As stated in the error message, you have to await for your main function as it is asynchronous. Borrowed from the Python3.7 documentation section about coroutines

Note that simply calling a coroutine will not schedule it to be executed

Given the fact that you want to run your toplevel entrypoint, in Python 3.7+ you should use

if __name__ == "__main__":
    asyncio.run(main())

For earlier versions you have to handle the event loop yourself:

if __name__ == "__main__":
    loop = asyncio.get_event_loop()
    loop.run_until_complete(main())