Investigate issues with gevent.monkey.patch_all()

Is your feature request related to a problem? Please describe.

Users on an older version of gevent (1.5.0) reported that running gevent.monkey.patch_all() breaks workflow asyncio.

Describe the solution you’d like

• Replicate the error on that gevent version (a simple workflow is probably fine)
• Upgrade gevent to see if it still occurs
  • If not, essentially bisect to find offending version minimum and maybe document in README
  • If so, find workaround and document in README

[alecgorge]

Thanks for the context. I am planning on testing our gevent setup with Temporal. I will report back the results w/gevent version once I have done so

[cretz]

Also, changing _(s|g)et_running_loop to (s|g)et_event_loop is a good idea to prevent changes in the private API from breaking things.

Completely agree, but there was something w/ the default event loop policy on some platform I think was causing me problems. But I forget what and I didn’t document it, so will definitely try to move back to all public API.

The only approach I can think of […]

We really have to keep our custom event loop. It’s the underpinning of what makes workflows work well.

Maybe we can have a similar monkey patch that overrides gevent for the life of the run_once and then puts it back after. I’ll have to check gevent, but surely we’re not the first that have wanted to do advanced asyncio loop management in a gevent-enabled process. I’ll have to dig into what they really do. I only need a short synchronous window to own the loop on a thread run.