Unable to install on Mac OS X due to errors with greenlet

Hi, I’m trying to install Locust on Mac OS X 10.11.3 El Capitan; I’ve installed libevent with brew and everything was ok. Then I tried to install locust with pip install locustio, and after lots of warnings the installation completes, but when I try to start locust I get this error:

Traceback (most recent call last):
  File "/usr/local/bin/locust", line 5, in <module>
    from pkg_resources import load_entry_point
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 2793, in <module>
    working_set.require(__requires__)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 673, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 576, in resolve
    raise DistributionNotFound(req)
pkg_resources.DistributionNotFound: greenlet>=0.4.9

And, if I try to re-install locust with Pip, I get this error at the end, relative to greenlet:

Command /System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python -c "import setuptools;__file__='/private/var/folders/vg/s4jrqr550319kf9qx7btjtmr0000gn/T/pip_build_myuserid/greenlet/setup.py';exec(compile(open(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /var/folders/vg/s4jrqr550319kf9qx7btjtmr0000gn/T/pip-VErCi5-record/install-record.txt --single-version-externally-managed failed with error code 1 in /private/var/folders/vg/s4jrqr550319kf9qx7btjtmr0000gn/T/pip_build_myuserid/greenlet

Am I missing something?

[cooperka]

Try pip install --user locustio instead of using sudo.

[davidgracie]

I was having install problems too but I fixed mine by installing command line tools: xcode-select --install