[ANN] kgio library / RubyGem

Eric Wong normalperson at yhbt.net
Mon Sep 27 23:03:02 EDT 2010

Hello all,

I've released kgio, a kinder, gentler I/O library for Ruby.  Some of its
features are useful for Unicorn, and all of it is useful for Rainbows!

I intend to make kgio a requirement for both Unicorn and
Rainbows!/Zbatery.  I'm comfortable with the code, but extra testers and
extra eyes to review it would be helpful (it's nearly all C).

There were several factors leading the creation of this library:

  1. The performance loss from Ruby 1.9.2 due to extending exceptions
     with IO::Wait{Read,Writ}able is annoying.  While it's partly
     fixed[1] and fixable[2] for 1.9.3, it could be a while before
     1.9.3 is available.  Unicorn currently does non-blocking accept
     very aggressively.

  2. (Rainbows! only) Slicing partially written strings for
     non-blocking I/O in gets painful with Ruby 1.9, it's much easier
     (at least for me) to do this in C and kgio_trywrite allows
     exactly that, returning the unwritten portion of a string.

  3. (Rainbows! only) It offers hooks for using alternative
     methods to switch execution contexts (experience taken from
     building the FiberSpawn/FiberPool modules).

  4. (philosophical) I've never considered EAGAIN/EINPROGRESS
     "exceptional" conditions when explicitly doing non-blocking
     I/O, and thus unworthy of raising exceptions.

kgio currently passes all tests on on Linux 2.6 (1.9.{1,2},
1.8.{6,7}, rbx 1.1) and FreeBSD 7.0 (1.8.7).


[1] - http://thread.gmane.org/gmane.comp.lang.ruby.core/30854
[2] - http://thread.gmane.org/gmane.comp.lang.ruby.core/31801

Eric Wong

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