GEMFILE(5) GEMFILE(5)

NAME

Gemfile - A format for describing gem dependencies for Ruby programs

SYNOPSIS

A Gemfile describes the gem dependencies required to execute associated
Ruby code.

Place the Gemfile in the root of the directory containing  the  associ-
ated  code.  For instance, in a Rails application, place the Gemfile in
the same directory as the Rakefile.

SYNTAX

A Gemfile is evaluated as Ruby code, in a context which makes available
a number of methods used to describe the gem requirements.

SOURCES (source)

At  the  top of the Gemfile, add one line for each Rubygems source that
might contain the gems listed in the Gemfile.

    source "http://rubygems.org"
    source "http://gems.github.com"

Each of these _source_s MUST be a valid Rubygems repository.

GEMS (gem)

    Specify gem requirements using the gem method, with the following argu-
    ments. All parameters are OPTIONAL unless otherwise specified.

NAME (required)
    For each gem requirement, list a single gem line.

        gem "nokogiri"

VERSION
    Each gem MAY have one or more version specifiers.

        gem "nokogiri", ">= 1.4.2"
        gem "RedCloth", ">= 4.1.0", "< 4.2.0"

REQUIRE AS (:require)
    Each  gem  MAY specify files that should be used when autorequiring via
    Bundler.require. You may pass an array with multiple files, or false to
    prevent any file from being autorequired.

        gem "sqlite3-ruby", :require => "sqlite3"
        gem "redis", :require => ["redis/connection/hiredis", "redis"]
        gem "webmock", :require => false

    The  argument  defaults  to the name of the gem. For example, these are
    identical:

        gem "nokogiri"
        gem "nokogiri", :require => "nokogiri"

GROUPS (:group or :groups)
    Each gem MAY specify membership in one or more  groups.  Any  gem  that
    does  not  specify  membership  in  any  group is placed in the default
    group.

        gem "rspec", :group => :test
        gem "wirble", :groups => [:development, :test]

    The Bundler runtime allows its  two  main  methods,  Bundler.setup  and
    Bundler.require, to limit their impact to particular groups.

        # setup adds gems to Ruby's load path
        Bundler.setup                    # defaults to all groups
        require "bundler/setup"          # same as Bundler.setup
        Bundler.setup(:default)          # only set up the _default_ group
        Bundler.setup(:test)             # only set up the _test_ group (but `not` _default_)
        Bundler.setup(:default, :test)   # set up the _default_ and _test_ groups, but no others

        # require requires all of the gems in the specified groups
        Bundler.require                  # defaults to just the _default_ group
        Bundler.require(:default)        # identical
        Bundler.require(:default, :test) # requires the _default_ and _test_ groups
        Bundler.require(:test)           # requires just the _test_ group

    The  Bundler CLI allows you to specify a list of groups whose gems bun-
    dle install should not install with the --without  option.  To  specify
    multiple  groups  to ignore, specify a list of groups separated by spa-
    ces.

        bundle install --without test
        bundle install --without development test

    After running bundle install --without test, bundler will remember that
    you excluded the test group in the last installation. The next time you
    run bundle install, without any --without option, bundler  will  recall
    it.

    Also,  calling  Bundler.setup  with  no  parameters, or calling require
    "bundler/setup" will setup all groups except for the ones you  excluded
    via --without (since they are obviously not available).

    Note  that on bundle install, bundler downloads and evaluates all gems,
    in order to create a single canonical list of all of the required  gems
    and  their dependencies. This means that you cannot list different ver-
    sions of the same gems in  different  groups.  For  more  details,  see
    Understanding Bundler http:/%rgembundler.com/rationale.html.

PLATFORMS (:platforms)
    If  a  gem should only be used in a particular platform or set of plat-
    forms, you can specify them. Platforms  are  essentially  identical  to
    groups,  except  that you do not need to use the --without install-time
    flag to exclude groups of gems for other platforms.

    There are a number of Gemfile platforms:

    ruby   C Ruby (MRI) or Rubinius, but NOT Windows

    ruby_18
           ruby AND version 1.8

    ruby_19
           ruby AND version 1.9

    mri    Same as ruby, but not Rubinius

    mri_18 mri AND version 1.8

    mri_19 mri AND version 1.9

    rbx    Same as ruby, but only Rubinius (not MRI)

    jruby  JRuby

    mswin  Windows

    mingw  Windows 'mingw32' platform (aka RubyInstaller)

    mingw_18
           mingw AND version 1.8

    mingw_19
           mingw AND version 1.9

    As with groups, you can specify one or more platforms:

        gem "weakling",   :platforms => :jruby
        gem "ruby-debug", :platforms => :mri_18
        gem "nokogiri",   :platforms => [:mri_18, :jruby]

    All  operations  involving  groups  (bundle   install,   Bundler.setup,
    Bundler.require)  behave exactly the same as if any groups not matching
    the current platform were explicitly excluded.

GIT (:git)
    If necessary, you can specify that a gem is located at a particular git
    repository.        The       repository       can       be       public
    (http:/%rgithub.com/rails/rails.git)             or              private
    (git@github.com:rails/rails.git).  If  the  repository  is private, the
    user that you use to run bundle install MUST have the appropriate  keys
    available in their $HOME/.ssh.

    Git  repositories  are  specified  using the :git parameter. The group,
    platforms, and require options are available  and  behave  exactly  the
    same as they would for a normal gem.

        gem "rails", :git => "git://github.com/rails/rails.git"

    A  git  repository  SHOULD  have  at least one file, at the root of the
    directory containing the gem, with the extension  .gemspec.  This  file
    MUST  contain  a  valid gem specification, as expected by the gem build
    command. It MUST NOT have any dependencies, other than on the files  in
    the  git  repository  itself  and any built-in functionality of Ruby or
    Rubygems.

    If a git repository does not have a .gemspec, bundler will  attempt  to
    create one, but it will not contain any dependencies, executables, or C
    extension compilation instructions. As a result, it may fail  to  prop-
    erly integrate into your application.

    If  a  git  repository does have a .gemspec for the gem you attached it
    to, a version specifier, if provided, means that the git repository  is
    only  valid  if  the  .gemspec specifies a version matching the version
    specifier. If not, bundler will print a warning.

        gem "rails", "2.3.8", :git => "git://github.com/rails/rails.git"
        # bundle install will fail, because the .gemspec in the rails
        # repository's master branch specifies version 3.0.0

    If a git repository does not have a .gemspec for the gem  you  attached
    it to, a version specifier MUST be provided. Bundler will use this ver-
    sion in the simple .gemspec it creates.

    Git repositories support a number of additional options.

    branch, tag, and ref
           You MUST only specify at most one of these options. The  default
           is :branch => "master"

    submodules
           Specify  :submodules => true to cause bundler to expand any sub-
           modules included in the git repository

    If a git repository contains multiple .gemspecs, each  .gemspec  repre-
    sents  a  gem located at the same place in the file system as the .gem-
    spec.

        |~rails                   [git root]
        | |-rails.gemspec         [rails gem located here]
        |~actionpack
        | |-actionpack.gemspec    [actionpack gem located here]
        |~activesupport
        | |-activesupport.gemspec [activesupport gem located here]

    To install a gem located in a git repository, bundler  changes  to  the
    directory  containing the gemspec, runs gem build name.gemspec and then
    installs the resulting gem. The gem build command, which comes standard
    with  Rubygems,  evaluates the .gemspec in the context of the directory
    in which it is located.

PATH (:path)
    You can specify that a gem is located in a particular location  on  the
    file system. Relative paths are resolved relative to the directory con-
    taining the Gemfile.

    Similar to the semantics of the :git option, the :path option  requires
    that  the directory in question either contains a .gemspec for the gem,
    or that you specify an explicit version that bundler should use.

    Unlike :git, bundler does not compile C extensions for  gems  specified
    as paths.

        gem "rails", :path => "vendor/rails"

BLOCK FORM OF GIT, PATH, GROUP and PLATFORMS

The  :git,  :path,  :group,  and :platforms options may be applied to a
group of gems by using block form.

    git "git://github.com/rails/rails.git" do
      gem "activesupport"
      gem "actionpack"
    end

    platforms :ruby do
      gem "ruby-debug"
      gem "sqlite3-ruby"
    end

    group :development do
      gem "wirble"
      gem "faker"
    end

In the case of the git block form, the :ref, :branch, :tag,  and  :sub-
modules  options  may  be passed to the git method, and all gems in the
block will inherit those options.

GEMSPEC (gemspec)

If you wish to use Bundler to help install dependencies for a gem while
it  is being developed, use the gemspec method to pull in the dependen-
cies listed in the .gemspec file.

The gemspec method adds any runtime dependencies as gem requirements in
the  default  group.  It  also  adds  development  dependencies  as gem
requirements in the development group. Finally, it adds a gem  require-
ment on your project (:path => '.'). In conjunction with Bundler.setup,
this allows you to require project files in your test code as you would
if  the  project  were  installed as a gem; you need not manipulate the
load path manually or require project files via relative paths.

The gemspec  method  supports  optional  :path,  :name,  and  :develop-
ment_group options, which control where bundler looks for the .gemspec,
what named .gemspec it uses (if more than one is  present),  and  which
group development dependencies are included in.

SOURCE PRIORITY

When  attempting  to locate a gem to satisfy a gem requirement, bundler
uses the following priority order:

1.  The source explicitly attached to the gem (using :path or :git)

2.  For implicit gems (dependencies of explicit gems), any git or  path
    repository otherwise declared. This results in bundler prioritizing
    the ActiveSupport gem from the Rails git repository over ones  from
    rubygems.org

3.  The  sources  specified  via  source, searching each source in your
    Gemfile from last added to first added.

                            May 2012                         GEMFILE(5)