Zeus preloads your Rails app so that your normal development tasks such as
generate, and specs/tests take less than one second.
This screencast gives a quick overview of how to use zeus with Rails.
More technically speaking, Zeus is a language-agnostic application checkpointer for non-multithreaded applications. Currently only ruby is targeted, but explicit support for other languages is on the horizon.
- OS X 10.7+ OR Linux 2.6.13+
- Rails 3.0+ (Support for other versions is not difficult and is planned.)
- Ruby 1.9.3+ with backported GC from Ruby 2.0 OR Rubinius
You can install the GC-patched ruby from this gist or from RVM. This is not actually 100% necessary, especially if you have a lot of memory. Feel free to give it a shot first without, but if you're suddenly out of RAM, switching to the GC-patched ruby will fix it.
Install the gem.
gem install zeus zeus init
Q: "I should put it in my
A: You can, but running
bundle exec zeus instead of
zeus can add precious seconds to a command that otherwise would be quite a bit faster. Zeus was built to be run from outside of bundler.
Start the server:
See a list of the available commands:
Run some commands:
zeus console zeus server zeus testrb test/unit/widget_test.rb zeus rspec spec/widget_spec.rb zeus generate model omg zeus rake -T zeus runner omg.rb
To add/modify commands, see
To get started hacking on Zeus itself, see
See also the handy contribution guide at