[openstack-dev] [oslo] Add a new aiogreen executor for Oslo Messaging

Robert Collins robertc at robertcollins.net
Mon Nov 24 00:14:17 UTC 2014

On 24 November 2014 at 12:35, Donald Stufft <donald at stufft.io> wrote:
> For whatever it’s worth, I find explicit async io to be _way_ easier to
> understand for the same reason I find threaded code to be a rats nest.
> The co-routine style of asyncio (or Twisted’s inlineCallbacks) solves
> almost all of the problems that I think most people have with explicit
> asyncio (namely the callback hell) while still getting the benefits.

Sure. Note that OpenStack *was* using inlineCallbacks.

> Glyph wrote a good post that mirrors my opinions on implicit vs explicit
> here: https://glyph.twistedmatrix.com/2014/02/unyielding.html.

That is, we chose
4. and finally, implicit coroutines: Java’s “green threads”, Twisted’s
Corotwine, eventlet, gevent, where any function may switch the entire
stack of the current thread of control by calling a function which
suspends it.

- the option that Glyph (and I too) would say to never ever choose.

My concern isn't that asyncio is bad - its not. Its that we spent an
awful lot of time and effort rewriting nova etc to be 'option 4', and
we've no reason to believe that whatever it was that made that not
work /for us/ has been fixed.


Robert Collins <rbtcollins at hp.com>
Distinguished Technologist
HP Converged Cloud

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