Rip: Ruby's Intelligent Packaging

Rip is an attempt to create a next generation packaging system for Ruby.

For more thorough documentation please see the Rip site:

Introduction

Let's get right to it then, shall we?

First we install rip.

$ sudo gem install rip

Did that work?

$ rip check
All systems go.

Yep. Let's see what libraries rip knows about.

$ rip list
ripenv: base

nothing installed

None. Really? Let's try to require Grit.

$ ruby -r grit -e 'puts Grit'
ruby: no such file to load -- grit (LoadError)

Whoops. Not found. Let's install the latest using rip.

$ rip install git://github.com/defunkt/grit.git v1.1.1b
Successfully installed grit v1.1.1
$ rip list
ripenv: base

diff-lcs (491fbc0)
mime-types (v1.16)
grit (v1.1.1)

Great, now we have Grit and all its dependencies.

$ ruby -r grit -e 'puts Grit'
Grit
$ ruby -r grit -e 'puts MIME::Types'
MIME::Types

And we don't need any magical require statements to use them!

If we'd like, we can now move between rip environments to mix and match libraries.

$ rip env create my_fresh_env
ripenv: created my_fresh_env
$ ruby -r grit -e 'puts Grit'
ruby: no such file to load -- grit (LoadError)

And so much more.

Overview

Inspired by Python's virtualenv and pip, Rip aims to be a simple and powerful way to install and manage Ruby packages.

Multiple Package Support

Rip can install from a variety of sources: directories, single files, git repositories - even Rubygems.

Adding a new package is easy and we expect Rip to support more formats in the future.

Virtual Environments

Virtual environments ("ripenvs") can be created so multiple versions of a package may be installed and used by different applications concurrently.

ripenvs are easy to create, copy, delete, and share. Recipes for creating ripenvs are trivial to generate and publish.

Install-time Dependency Resolution

Dependency checking happens when Rip packages are installed, not when packages run.

A dependency graph is constructed for the entire virtual environment, making it easy to debug leaf-node transitive dependency issues.

Clear Error Messages

Installation and dependency errors should be clear and give as much information as possible in order to help you fix the problem.

Few Dependencies

Rip itself should work without anything but the Ruby standard library, for maximum portability.

Rip vs RubyGems

No building

Rip's support for a variety of package types means there is nothing to build and distribute.

Tag your Git repository and publicize the latest version, or just pass around Gists. Rip does not care.

Rip dependencies are listed as separate lines in a plaintext file and can reference any package type. As a result, Rip packages can depend on existing Rubygems that aren't available from any other source.

This means projects unaware of Rip can be installed by Rip and managed by ripenvs. Adding the dependencies yourself is easy.

Multiple Environments

Rip makes it easy to have multiple environments with different versions of libraries.

You could even clone a ripenv then upgrade a single library to test its impact on the environment as a whole. Installation not go smoothly? Delete the new ripenev then continue using the stable one.

Dependency Conflict Resolution

With Rip, version conflicts in dependencies are simpler to resolve: you know exactly what version of which libraries are requesting which versions of the same library at installation time. As a result conflicts are resolved when you're thinking about installing your code, not later on when you're thinking about running it.

Hands off

Rip requires no changes to your code, only an optional deps.rip file added to the root of your project. As a result you do not force Rip on anyone else and individuals are free to re-package your code using other systems.

Distributed

There is no canonical server for Rip packages, which may be good or bad.

Installing Packages

Each Rip package optionally contains at the root a deps.rip file identifying it as a Rip package and listing its dependencies.

Let's take the ambition project as an example. This is its deps.rip in full:

git://github.com/drnic/rubigen.git REL-1.3.0
git://github.com/seattlerb/ruby2ruby.git e3cf57559 # 1.1.8
git://github.com/seattlerb/parsetree.git 480ede9d9 # 2.1.1

If you were to run rip install git://github.com/defunkt/ambition the following steps would occur:

The source would be fetched and unpacked as ambition in the cwd
The source of each dependency in deps.rip would be fetched
Each dependency would be unpacked into the current ripenv at the revision or tag specified
Each dependency's deps.rip would be fetched and unpacked into the ripenv, etc

As this process unfolds, a mapping of libraries and versions is kept in memory. When a library is declared multiple times at different versions the process is halted and the error reported.

If you've cloned ambition on your own you can still install the dependencies using rip install deps.rip

Uninstalling Packages

The easiest way to mass uninstall packages is to delete your ripenv and create a new one. Otherwise, rip uninstall package will do the trick.

Rip will complain if you attempt to uninstall a package that others depend on. To remove the package anyway, use -y. To remove the package and the dependents, use -d (for dependents).

Extensions

Installing a package that is not Rip aware but needs an extension built? Use rip build.

Rip will attempt to run rake rip:install in your library if a Rakefile is found. If you need to compile your C extension or do any other work, this is the place.

Rip Directory Structure

Rip is currently user-specific.

Here is a typical directory structure for Rip:

rip/
  - rip-packages/
  - active/
    - bin/
    - lib/  
  - base/
    - bin/
    - lib/
    - base.ripenv    
  - cheat/
    - bin/
    - lib/
    - cheat.ripenv     
  - thunderhorse/
    - bin/
    - lib/
    - thunderhorse.ripenv

The above contains three ripenvs: base, cheat, and thunderhorse. Each ripenv contains directories for executable binaries and Ruby source files. They also include a generated .ripenv file containing metadata about the ripenev and its packages.

This individual may use base for general tomfoolery (it's the default), cheat for developing their Cheat application, and thunderhorse for working on their new Thunderhorse project.

active is a symlink to the current, active ripenv. We also see a rip-packages directory. This is where Rip stores the raw repositories.

Let us focus on the cheat ripenv:

rip/
  - cheat/
    - bin/
      - camping
    - lib/
      - markaby/
        - builder.rb
        - cssproxy.rb
        - metaid.rb
        - rails.rb
        - tags.rb
        - template.rb
      - markaby.rb
      - camping/
        - db.rb
        - fastcgi.rb
        - reloader.rb
        - session.rb
        - webrick.rb
      - camping-unabridged.rb
      - camping.rb
    - cheat.ripenv

When using the cheat ripenv, a camping binary will be in our PATH.

When running Ruby scripts, or even executing the camping binary, rip/cheat/lib will be in our $LOAD_PATH. Therefor we may, for instance, require "markaby" in a Ruby script and it will succeed.

In any other ripenv, the cheat ripenv's binaries and libraries are as good as non-existant.

Deployment

Want to get a copy of your local environment on your deployment server? Generate a .rip file with rip freeze then upload and install it.

Shortcomings

Currently it's UNIX-only. This is because Rip needs to manipulate the RUBYLIB and PATH environment variables so that Ruby knows where to find installed Rip packages.

As a result, the setup script expects you to be running bash or zshell.

Contributors

Chris Wanstrath (that's me!)
Jeff Hodges
Tom Preston-Werner
John Barnette
Blake Mizerany
Ryan Tomayko
Pat Nakajima

Special Thanks

Coda Hale for the phrase "leaf-node transitive dependency issues"
GitHub for sponsoring development

wwood/rip