Ruby
There currently is support to bundle applications that are packaged as Ruby gems. The utility "bundix" allows you to write a Gemfile, let bundler create a Gemfile.lock, and then convert this into a nix expression that contains all Gem dependencies automatically.
For example, to package sensu, we did:
Gemfile
source 'https://rubygems.org'
gem 'sensu'
$ $(nix-build '' -A bundix --no-out-link)/bin/bundix --magic
$ cat > default.nix
{ lib, bundlerEnv, ruby }:
bundlerEnv rec {
name = "sensu-${version}";
version = (import gemset).sensu.version;
inherit ruby;
# expects Gemfile, Gemfile.lock and gemset.nix in the same directory
gemdir = ./.;
meta = with lib; {
description = "A monitoring framework that aims to be simple, malleable, and scalable";
homepage = "http://sensuapp.org/";
license = with licenses; mit;
maintainers = with maintainers; [ theuni ];
platforms = platforms.unix;
};
}]]>
Please check in the Gemfile, Gemfile.lock and the gemset.nix so future updates can be run easily.
Updating Ruby packages can then be done like this:
For tools written in Ruby - i.e. where the desire is to install a package and then execute e.g. rake at the command line, there is an alternative builder called bundlerApp. Set up the gemset.nix the same way, and then, for example:
The chief advantage of bundlerApp over bundlerEnv is the executables introduced in the environment are precisely those selected in the exes list, as opposed to bundlerEnv which adds all the executables made available by gems in the gemset, which can mean e.g. rspec or rake in unpredictable versions available from various packages.
Resulting derivations for both builders also have two helpful attributes, env and wrappedRuby. The first one allows one to quickly drop into nix-shell with the specified environment present. E.g. nix-shell -A sensu.env would give you an environment with Ruby preset so it has all the libraries necessary for sensu in its paths. The second one can be used to make derivations from custom Ruby scripts which have Gemfiles with their dependencies specified. It is a derivation with ruby wrapped so it can find all the needed dependencies. For example, to make a derivation my-script for a my-script.rb (which should be placed in bin) you should run bundix as specified above and then use bundlerEnv like this: