Ruby + Nix

gistfile1.txt

{
  oldPkgs ? import (fetchGit {
    url = https://github.com/NixOS/nixpkgs;
    ref = "3b9b8726bdbb5405919c40920d9693c5eae246b5";
  }) {},
  newPkgs ? import (fetchGit {
    url = https://github.com/NixOS/nixpkgs;
    ref = "nixos-19.03";
  }) {}
}:

let
  ruby = oldPkgs.ruby_2_1_10;
in newPkgs.mkShell {
  buildInputs = with newPkgs; [
    ruby
    libxml2.dev
    libxslt.dev
    newPkgs.parallel
    oldPkgs.mysql55
    oldPkgs.openssl
    oldPkgs.redis
    oldPkgs.nodejs
    newPkgs.imagemagick
  ];

  shellHook = ''
    mkdir -p .local-data/gems
    export GEM_HOME=$PWD/.local-data/gems
    export GEM_PATH=$GEM_HOME

    export PATH="$GEM_PATH/bin:$PATH"

    gem install bundler -v '1.15.4'
    gem install nokogiri -v '1.5.11' -- --with-xml2-lib=${newPkgs.libxml2.dev}/lib \
       --with-xml2-include=${newPkgs.libxml2.dev}/include/libxml2
    gem install mysql2 -v '0.3.21'

    mkdir -p .local-data/mysql/data

    if [ -z "$(ls -A .local-data/mysql/data)" ]; then
      mysql_install_db --datadir="$PWD/.local-data/mysql/data" --socket="$PWD/.local-data/mysql/mysqld.sock"
    fi
  '';
}