1. Yes, file functions from your gist do block event loop. 2. Yes, portable nonblocking file API should be built on threads. Or, as an option, you can make *actually blocking* code with *nonblocking interface* if you like coroutines so much.
On Tue, Jan 13, 2015 at 4:54 PM, Luciano Ramalho <[email protected]> wrote: > Reviving the thread... if I understand correctly, there is no portable way > to do disk I/O asynchronously (and the gist [1] provided by the OP is bogus: > the read_data function will block the event loop). Is my understanding > correct? > > [1] https://gist.github.com/kunev/f83146d407c81a2d64a6 > > Second question: Node.js does have a complete async API for doing filesysem > I/O, even an async stat function! But after reading Glyph's Q&A on > Stackoverflow I conclude those filesystem I/O functions in Node must rely on > threads underneath, since we can't rely on OS APIs for async filesystem I/O. > Is that it? > > Thanks! > > Best, > > Luciano > > > On Tuesday, August 26, 2014 at 11:11:51 PM UTC-3, Glyph Lefkowitz wrote: >> >> If anyone is curious about the abysmal state of asynchronous file I/O in >> popular operating systems, this question I asked on Stack Overflow a while >> back has got some really excellent answers on it: >> <https://stackoverflow.com/questions/87892/what-is-the-status-of-posix-asynchronous-i-o-aio>. >> >> -glyph >> >> On Aug 25, 2014, at 6:55 PM, Guido van Rossum <[email protected]> wrote: >> >> On most OSes, select() and other polling APIs always report disk files to >> be "ready", so you basically can't use asyncio with them. On Windows it will >> fail; on *n*x it will appear to work but actually you are doing the whole >> thing synchronously. The only way to overlap disk I/O with asyncio events >> would be to do the disk I/O on a separate thread. >> >> Someone is working on sendfile support >> (https://code.google.com/p/tulip/issues/detail?id=144, >> http://bugs.python.org/issue17552) which would help overlap disk I/O and >> socket I/O for the specific case of serving a file from disk directly to a >> socket, but even that would be pretty limited. >> >> >> On Mon, Aug 25, 2014 at 3:06 PM, Ludovic Gasc <[email protected]> wrote: >>> >>> Hi, >>> >>> I'm looking for the best way to read/write files with AsyncIO. >>> Ideally, I want to r/w asynchronously, like with network. >>> >>> I've found this: https://gist.github.com/kunev/f83146d407c81a2d64a6 >>> >>> Is it ok, or do you have a better suggestion ? >>> >>> Regards. >> >> >> >> >> -- >> --Guido van Rossum (python.org/~guido) >> >> > -- Thanks, Andrew Svetlov
