dldinternet/appbundler

Generate locked binstubs for ruby applications

Appbundler

Appbundler reads a Gemfile.lock and generates code with gem "some-dep", "= VERSION" statements to lock the app's dependencies to the versions selected by bundler. This code is used in binstubs for the application so that running (e.g.) chef-client on the command line activates the locked dependencies for chef before running the command.

This provides the following benefits:

• The application loads faster because rubygems is not resolving dependency constraints at runtime.
• The application runs with the same dependencies that it would if bundler was used, so we can test applications (that will be installed in an omnibus package) using the default bundler workflow.
• There's no need to bundle exec or patch the bundler runtime into the app.
• The app can load gems not included in the Gemfile/gemspec. Our use case for this is to load plugins (e.g., for knife and test kitchen).
• A user can use rvm and still use the application (see below).
• The application is protected from installation of incompatible dependencies.

Usage

Install via rubygems: gem install appbundler or clone this project and bundle install:

git clone https://github.com/opscode/appbundler.git
cd appbundler
bundle install

Clone whatever project you want to appbundle somewhere else, and bundle install it:

mkdir ~/oc
cd ~/oc
git clone https://github.com/opscode/chef.git
cd chef
bundle install

Create a bin directory where your bundled binstubs will live:

mkdir ~/appbundle-bin
# Add to your PATH if you like

Now you can app bundle your project (chef in our example):

bin/appbundler ~/oc/chef ~/appbundler-bin

Now you can run all of the app's executables with locked down deps:

~/appbunlder-bin/chef-client -v

RVM

The generated binstubs explicitly disable rvm, so the above won't work if you're using rvm. This is intentional, because our use case is for omnibus applications where rvm's environment variables can break the embedded application by making ruby look for gems in rvm's gem repo.