Zeus
Zeus preloads your Rails app so that your normal development tasks such as console
, server
, generate
, and specs/tests take less than one second.
This screencast gives a quick overview of how to use zeus with Rails.
Zeus is also covered in RailsCasts episode 412.
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.
Requirements (for use with Rails)
- OS X 10.7+ OR Linux 2.6.13+
- Rails 3.x
- Compatible Ruby installation
- Ruby 1.9.3+ with backported GC from Ruby 2.0 (rbenv instructions, rvm instructions)
- Ruby 2.0
- Rubinius
For Ruby 1.9.3+, GC patches are 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.
Please note: Zeus requires your project to be running on a file system that supports FSEvents or inotify.
Installation
Install the gem.
gem install zeus
Q: "I should put it in my Gemfile
, right?"
A: No. You can, but running bundle exec zeus
instead of zeus
adds precious seconds to commands that otherwise would be quite a bit faster. Zeus was built to be run from outside of bundler.
IMPORTANT
It is common to see tests running twice when starting out with Zeus. If you see your tests/specs running twice, you should try disabling require 'rspec/autotest'
and require 'rspec/autorun'
(for RSpec), or require 'minitest/autorun'
(for Minitest). (see #134 for more information).
Usage
Start the server:
zeus start
The server will print a list of available commands.
Run some commands in another shell:
zeus console
zeus server
zeus test test/unit/widget_test.rb
zeus test spec/widget_spec.rb
zeus generate model omg
zeus rake -T
zeus runner omg.rb
Limitations
You need to restart zeus if you make changes to various initialization files. Examples of these files include:
- FactoryGirl factories
- RSpec support files
Related gems
- Spork - a DRb server that forks before each run to ensure a clean testing state
- Commands - a persistent console that runs Rails commands without reloading the env
- Spring - like Zeus but in pure Ruby, totally automatic, alpha and limited compatibility
If you're switching from Spork, be sure to read the wiki page on Spork.
Customizing Zeus Commands
To add/modify commands, see docs/ruby/modifying.md
.
Contributing
To get started hacking on Zeus itself, see docs/overview.md
.
See also the handy contribution guide at contributing.md
.
Rails 2.3 Support
The default plan bundled with zeus only supports Rails 3.x. There is a project (currently WIP) to provide Rails 2.3 support at https://github.com/tyler-smith/zeus-rails23.