How can I install the Python library 'gevent' on Mac OS X Lion

Question

Python library gevent, version 0.13.6 (the current version on PyPI) will not pip install on OS X Lion, Python 2.7 (and probably others.) It works fine on Snow Leopard.

How can I get this library installed?

Bonus points if it can be done using pip install, rather than a manual or custom process, because then it will play nicely with automated builds.

Here is my pip install output:

pip install gevent
Downloading/unpacking gevent
  Running setup.py egg_info for package gevent

Requirement already satisfied (use --upgrade to upgrade): greenlet in ./tl_env/lib/python2.7/site-packages (from gevent)
Installing collected packages: gevent
  Running setup.py install for gevent
    building 'gevent.core' extension
    gcc-4.2 -fno-strict-aliasing -fno-common -dynamic -isysroot /Developer/SDKs/MacOSX10.6.sdk -arch i386 -arch x86_64 -g -O2 -DNDEBUG -g -O3 -I/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c gevent/core.c -o build/temp.macosx-10.6-intel-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:741: warning: parameter names (without types) in function declaration
    gevent/core.c: In function ‘__pyx_f_6gevent_4core___event_handler’:
    gevent/core.c:1619: error: ‘EV_READ’ undeclared (first use in this function)
    gevent/core.c:1619: error: (Each undeclared identifier is reported only once
    gevent/core.c:15376: warning: assignment makes pointer from integer without a cast
   [... about 1000 more lines of compiler errors...]
    gevent/core.c:15385: error: dereferencing pointer to incomplete type
    gevent/core.c: In function ‘__pyx_pf_6gevent_4core_4http___init__’:
    gevent/core.c:15559: warning: assignment makes pointer from integer without a cast
    gevent/core.c: At top level:
    gevent/core.c:21272: error: expected ‘)’ before ‘val’
    lipo: can't figure out the architecture type of: /var/folders/s5/t94kn0p10hdgxzx9_9sprpg40000gq/T//cczk54q7.out
    error: command 'gcc-4.2' failed with exit status 1
    Complete output from command /Users/jacob/code/toplevel/tl_env/bin/python -c "import setuptools;__file__='/Users/jacob/code/toplevel/tl_env/build/gevent/setup.py';exec(compile(open(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --single-version-externally-managed --record /var/folders/s5/t94kn0p10hdgxzx9_9sprpg40000gq/T/pip-s2hPd3-record/install-record.txt --install-headers /Users/jacob/code/toplevel/tl_env/bin/../include/site/python2.7:
    running install

running build

running build_py

running build_ext

building 'gevent.core' extension

gcc-4.2 -fno-strict-aliasing -fno-common -dynamic -isysroot /Developer/SDKs/MacOSX10.6.sdk -arch i386 -arch x86_64 -g -O2 -DNDEBUG -g -O3 -I/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c gevent/core.c -o build/temp.macosx-10.6-intel-2.7/gevent/core.o

Answer 1

Don't post the entire thing! That's too much! 90% of the time, the first error is enough...

gevent/libevent.h:9:19: error: event.h: No such file or directory

This means that the library which provides the event.h header is not installed. The library is called libevent (website).

In general, compilation errors like these are a flaw in the build scripts. The build script should give an error message that libevent is not installed, and it is a bug that it did not do so.

To get libevent from MacPorts and then manually tell compiler with CFLAGS environment variable where to find event.h and libevent while running pip.

sudo port install libevent
CFLAGS="-I /opt/local/include -L /opt/local/lib" pip install gevent

You can also use homebrew for installing libevent : brew install libevent
(from David Wolever's comment)