Wercker builds on top of Docker containers. Containers are a simple and reliable way to distribute software across platforms. Docker is native on Linux, but on OSX it relies on a virtual Linux host, like VirtualBox.
The easies wat to install the Docker Toolbox, which contains everything you need is Brew: brew install Caskroom/cask/dockertoolbox. It will automatically install VirtualBox as a dependency.
Download the binary to your bin directory:
curl -L https://goo.gl/m2LwRt -o /usr/local/bin/wercker
Make it executable so you can run it:
chmod 755 /usr/local/bin/wercker
The next step is to make Wercker talk to your Docker setup. For this we need to start the Docker deamon and setup a default host with the startup script that got installed in the step above:
sh /Applications/Docker/Docker Quickstart Terminal.app/Contents/Resources/Scripts/start.sh
It will start logging some output and ends with something that should resemble a whale. From here Wercker and Docker are connected and and we can run Wercker commands:
cd ~/my-project
wercker build
Happy Wercker-ing.
Tip: if it's a node project and you're also developing locally, Docker shares your node_modules folder and Wercker likely won't build.