A working python 2.7 installation is required. We recommend not to use the builtin OSX python. Instead you should use homebrew to install python:
brew install python27
If you prefer using macports run:
sudo port install python27
The following additional packages need to be installed:
brew install libevent
With macports:
sudo port install libevent
Java 7 is needed for crate:
If you have any problems with the installation try to set the environment variable JAVA_HOME in your shell rc file (~/.bashrc or ~/.zshrc):
export JAVA_HOME=`/usr/libexec/java_home`
Source the shell rc file and check the java version:
$ source ~/.bashrc
or
$ source ~/.zshrc
$ java -version
java version "1.7.0_..."
If the printed version is greater than or equal to 1.7.0 you have installed java sucsessfully.