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 its main file, which should be used when autore-
       quiring (Bundler.require).



	   gem "sqlite3-ruby", :require => "sqlite3"



       This defaults to the name of the gem itself. For  instance,  these  are
       identical:



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



       Specify	:require  =>  false to prevent bundler from requiring the gem,
       but still install it and maintain dependencies.

   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://gembundler.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://github.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, in the order in which they were
	   declared in the Gemfile.






				September 2011			    GEMFILE(5)
