For those who don’t know, PEP 3156 is a proposal for asynchronous I/O in Python, starting with Python 3.3. Until now each framework (Twisted, Tornado, …) has defined it’s own interface for defining protocols and transports. This makes very difficult if not impossible to reuse a protocol implementation across frameworks. PEP 3156 tries to fix that, among other things.
The reference implementation is called Tulip and can be found here. It’s a fast moving target, but it already contains working event loops for Windows and Unix systems. It uses pollers available in the select module for the Unix side, and a C module wrapping Windows IOCP functionality for Windows.
I was really excited to see this come through, so I started playing with it by implementing a pyuv based event loop. I called that it rose. It was a lot easier to implement than expected and it currently passes the entire test suite 🙂
I had the pleasure to give a presentation at the first ever Python Devroom at FOSDEM. I talked about how event loops work internally and how pyuv can help by abstracting a lot of the problems with a pretty simple to use API. I also introduced rose, a pyuv based PEP-3156 event loop implementation, but I’ll write a followup post on that 🙂
Thanks a lot to everyone who attended the talk, and for those who couldn’t here are the slides!