[sheng]

I'm always wondering why gevent never gets the same attention other concurrency frameworks do. From my point of view it looks like a very sweet library with useful tools and should work just fine in combination with gunicorn or uwsgi. I never had a chance to test it with some real work load though.

[camus2]

Problem is the lack of third party libraries that does IO the way gevent works, if your lib does blocking IO, there is no point using gevent.

NodeJS does async IO by default,so all nodejs libs do async IO.

My point is , it's not so much about wether ruby or python can have the same capabilities as nodejs they can,it's about wether async libs have an ecosystem to support them or not.

[jerf]

"Problem is the lack of third party libraries that does IO the way gevent works, if your lib does blocking IO, there is no point using gevent."

Here we probably see some of the problem. Gevent works in a way that most people don't expect, which is to hack the IO layer itself. You don't need a library to "support" gevent for it to still work within gevent. If the library's "synchronousness" is that it opens sockets and uses them, that Just Works in gevent; every time the library does a "blocking" operation in gevent, gevent replaces it with an entry in some sort of polling loop, and moves to the next eventlet that can do work. I used it to write a highly concurrent program that made a ton of simultaneous XML-RPC calls, and I used gevent + the default "blocking" XML-RPC library from Python's core library. It makes the ecosystem support async, at least for network, timers (sleep), and a few other things.

Gevent has other issues; I don't think it can do the same for disk IO. But especially if you've got a network heavy program, you can just drop gevent in and get perfectly cromulent async.

I think a lot of people don't quite understand this. The Node community's persistent and vocal false belief that "async == visibly event-based structure code" probably isn't helping. But it is also true that gevent is a legitimately weird hack on a language. Cool, but very unusual.

[drdaeman]

One can monkey-patch __builtins__, too, so `open("foo", "r").read()` will happily yield control to event loop. It's just that gevent doesn't do this.

Sounds like a great project to hack in spare time, though.

[drdaeman]

If you lib uses standard library primitives (sockets, pipes, subprocesses, etc) then gevent.monkey makes it cooperate.