Open Stack

Le lundi 7 juillet 2014, 11:26:27 Gordon Sim a écrit :
> > When we switch to asyncio's event loop, all of this code needs to be
> > ported to asyncio's explicitly asynchronous approach. We might do:
> >    @asyncio.coroutine
> >    
> >    def foo(self):
> >        result = yield from some_async_op(...)
> >        return do_stuff(result)
> > 
> > or:
> >    @asyncio.coroutine
> >    def foo(self):
> >        fut = Future()
> >        some_async_op(callback=fut.set_result)
> >        ...
> >        result = yield from fut
> >        return do_stuff(result)
> > 
> > Porting from eventlet's implicit async approach to asyncio's explicit
> > async API will be seriously time consuming and we need to be able to do
> > it piece-by-piece.
> 
> Am I right in saying that this implies a change to the effective API for
> oslo.messaging[1]? I.e. every invocation on the library, e.g. a call or
> a cast, will need to be changed to be explicitly asynchronous?
>
> [1] Not necessarily a change to the signature of functions, but a change
> to the manner in which they are invoked.

The first step is to patch endpoints to add @trollius.coroutine to the methods, 
and add yield From(...) on asynchronous tasks.

Later we may modify Oslo Messaging to be able to call an RPC method 
asynchronously, a method which would return a Trollius coroutine or task 
directly. The problem is that Oslo Messaging currently hides "implementation" 
details like eventlet. Returning a Trollius object means that Oslo Messaging 
will use explicitly Trollius. I'm not sure that OpenStack is ready for that 
today.

Victor