"RuntimeError: This event loop is already running" When attempting REPL example

Each time I attempt the REPl example, I get the traceback below. Sync context-manager example worked though. playwright==0.8.0 REPL Example: https://github.com/microsoft/playwright-python#repl-support-without-context-managers

IPython session

 jake  (e) venvplaywright  ~  ipython
/home/jake/.local/lib/python3.8/site-packages/IPython/core/interactiveshell.py:935: UserWarning: Attempting to work in a virtualenv. If you encounter problems, please install IPython inside the virtualenv.
  warn("Attempting to work in a virtualenv. If you encounter problems, please "
Python 3.8.3 (default, May 29 2020, 00:00:00) 
Type 'copyright', 'credits' or 'license' for more information
IPython 7.13.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: from playwright import sync_playwright                                                                                                                                                

In [2]: playwright = sync_playwright().start()                                                                                                                                                

Traceback (most recent call last):
  File "/usr/local/bin/ipython", line 11, in <module>
    sys.exit(start_ipython())
  File "/home/jake/.local/lib/python3.8/site-packages/IPython/__init__.py", line 126, in start_ipython
    return launch_new_instance(argv=argv, **kwargs)
  File "/home/jake/.local/lib/python3.8/site-packages/traitlets/config/application.py", line 664, in launch_instance
    app.start()
  File "/home/jake/.local/lib/python3.8/site-packages/IPython/terminal/ipapp.py", line 356, in start
    self.shell.mainloop()
  File "/home/jake/.local/lib/python3.8/site-packages/IPython/terminal/interactiveshell.py", line 558, in mainloop
    self.interact()
  File "/home/jake/.local/lib/python3.8/site-packages/IPython/terminal/interactiveshell.py", line 541, in interact
    code = self.prompt_for_code()
  File "/home/jake/.local/lib/python3.8/site-packages/IPython/terminal/interactiveshell.py", line 467, in prompt_for_code
    text = self.pt_app.prompt(
  File "/home/jake/.local/lib/python3.8/site-packages/prompt_toolkit/shortcuts/prompt.py", line 994, in prompt
    return self.app.run(set_exception_handler=set_exception_handler)
  File "/home/jake/.local/lib/python3.8/site-packages/prompt_toolkit/application/application.py", line 811, in run
    return loop.run_until_complete(
  File "/usr/lib64/python3.8/asyncio/base_events.py", line 592, in run_until_complete
    self._check_running()
  File "/usr/lib64/python3.8/asyncio/base_events.py", line 552, in _check_running
    raise RuntimeError('This event loop is already running')
RuntimeError: This event loop is already running

If you suspect this is an IPython 7.13.0 bug, please report it at:
    https://github.com/ipython/ipython/issues
or send an email to the mailing list at [e-mail]

You can print a more detailed traceback right now with "%tb", or use "%debug"
to interactively debug it.

Extra-detailed tracebacks for bug-reporting purposes can be enabled via:
    %config Application.verbose_crash=True

sys:1: RuntimeWarning: coroutine 'Application.run_async' was never awaited

[bubthegreat]

It’s been almost two years and this still isn’t fixed that I can find - playwright is explicitly stopping me from using nested loops:

import nest_asyncio
nest_asyncio.apply()
​
from playwright.sync_api import sync_playwright
playwright = sync_playwright().start()
---------------------------------------------------------------------------
Error                                     Traceback (most recent call last)
Input In [3], in <cell line: 2>()
      1 from playwright.sync_api import sync_playwright
----> 2 playwright = sync_playwright().start()

File c:\users\bubth\development\soc2\venv\lib\site-packages\playwright\sync_api\_context_manager.py:76, in PlaywrightContextManager.start(self)
     75 def start(self) -> SyncPlaywright:
---> 76     return self.__enter__()

File c:\users\bubth\development\soc2\venv\lib\site-packages\playwright\sync_api\_context_manager.py:42, in PlaywrightContextManager.__enter__(self)
     40             own_loop = loop
     41         if loop.is_running():
---> 42             raise Error(
     43                 """It looks like you are using Playwright Sync API inside the asyncio loop.
     44 Please use the Async API instead."""
     45             )
     47         def greenlet_main() -> None:
     48             loop.run_until_complete(self._connection.run_as_sync())

Error: It looks like you are using Playwright Sync API inside the asyncio loop.
Please use the Async API instead.

The workarounds don’t work for those of us using windows, and they don’t appear to work in WSL either - is there a reason we can’t get more information on why this is still closed two years later with no traction and no functional workarounds for presumably a fairly normal use case of using a jupyter notebook for exploratory programming?

It seems hard to believe that we just assume everyone will use raw iPython for everything so I’m confused by the reluctance to actually fix this.

If I’m understanding the asyncio base_events.py error, it’s because there’s no implementation of the _make_subprocess_transport function - is that not something that would be on the playwright package to implement in it’s async implementation?

[bubthegreat]

If I get time tonight ill play around with it- I dont see any reason for it not to run in the existing loop - or are there architectural challenges with it sharing the loop?

On Tue, Oct 6, 2020, 8:35 AM Pavel Feldman [e-mail] wrote:

My understanding is that resolving this requires cooperation between the embedder that controls the loop and sync Playwright that also wants to dispatch its messages forever. And I don’t think such cooperation is the right way to go. Sync API is designed as self-contained, assumes it controls execution. Is there a way to use async in Jupyter?

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