OSX + homebrew + gevent

I ran into some trouble installing gevent on OSX, but the solution was pretty straight forward. Unfortunately a simple pip install gevent fails:

$ pip install gevent-0.13.6.tar.gz 
Unpacking ./requirements/src/gevent-0.13.6.tar.gz
  Running setup.py egg_info for package from

  ...
    
    building 'gevent.core' extension
    /usr/bin/cc -fno-strict-aliasing -O3 -march=core2 -msse4.1 -w -pipe -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/brew/bin/../Cellar/python/2.7.1/include/python2.7 -c gevent/core.c -o build/temp.macosx-10.4-x86_64-2.7/gevent/core.o
    In file included from gevent/core.c:225:
    gevent/libevent.h:9:19: error: event.h: No such file or directory
    gevent/libevent.h:38:20: error: evhttp.h: No such file or directory
    gevent/libevent.h:39:19: error: evdns.h: No such file or directory
    gevent/core.c:361: error: field ‘ev’ has incomplete type

    ...

    gevent/core.c:15344: error: dereferencing pointer to incomplete type
    gevent/core.c:15358: error: dereferencing pointer to incomplete type
    gevent/core.c:15367: error: dereferencing pointer to incomplete type
    gevent/core.c:15385: error: dereferencing pointer to incomplete type
    gevent/core.c: At top level:
    gevent/core.c:21272: error: expected ‘)’ before ‘val’
    error: command '/usr/bin/cc' failed with exit status 1

The tail of the error message isn't particularly useful, it suggests there's an error in the C code. However toward the top we see the event.h: No such file or directory complaint which seems to indicate that libevent is needed (which makes sense). The solution is straight forward, just install libevent, then use pip to install gevent:

$ brew install libevent
$ export CFLAGS=-I/brew/include
$ pip install gevent-0.13.6.tar.gz

And then everything just worked. You'll notice my homebrew installation is at (the non-standard location of) /brew/, so you'll probably need to tailor that to your own situation.