Gemfile - A format for describing gem dependencies for Ruby programs
Gemfiledescribes the gem dependencies required to execute associated Ruby code.
Gemfile in the root of the directory containing the associated
code. For instance, in a Rails application, place the
Gemfile in the same
directory as the
Gemfile is evaluated as Ruby code, in a context which makes available
a number of methods used to describe the gem requirements.
At the top of the
Gemfile, add one line for each
Rubygems source that
might contain the gems listed in the
source "http://rubygems.org" source "http://gems.github.com"
Each of these _source_s
MUST be a valid Rubygems repository.
Specify gem requirements using the
gem method, with the following arguments.
All parameters are
OPTIONAL unless otherwise specified.
For each gem requirement, list a single gem line.
MAY have one or more version specifiers.
gem "nokogiri", ">= 1.4.2" gem "RedCloth", ">= 4.1.0", "< 4.2.0"
Require As (:require)
MAY specify its main file, which should be used when autorequiring
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"
:require => false to prevent bundler from requiring the gem, but still
install it and maintain dependencies.
Groups (:group Or :groups)
MAY specify membership in one or more groups. Any gem that does
not specify membership in any group is placed in the
gem "rspec", :group => :test gem "wirble", :groups => [:development, :test]
The Bundler runtime allows its two main methods,
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
bundle install should
not install with the
--without option. To specify multiple groups to ignore, specify a
list of groups separated by spaces.
bundle install --without test bundle install --without development test
bundle install --without test, bundler will remember that you excluded
the test group in the last installation. The next time you run
--without option, bundler will recall it. You can run
bundle install --without '' to install all gems with all groups active (none skipped).
Bundler.setup with no parameters, or calling
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 versions of the same gems in different
groups. For more details, see Understanding Bundler.
If a gem should only be used in a particular platform or set of platforms, 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
There are a number of
- C Ruby (MRI) or Rubinius, but
- Same as ruby, but not Rubinius
- Same as ruby, but only Rubinius (not MRI)
- Windows 'mingw32' platform (aka RubyInstaller)
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 (
Bundler.require) behave exactly the same as if any groups not
matching the current platform were explicitly excluded.
If necessary, you can specify that a gem is located at a particular
git repository. The repository can be public (
or private (
email@example.com:rails/rails.git). If the repository is private,
the user that you use to run
MUST have the appropriate
keys available in their
Git repositories are specified using the
:git parameter. The
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
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 properly
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
version in the simple
.gemspec it creates.
Git repositories support a number of additional options.
MUSTonly specify at most one of these options. The default is
:branch => "master"
:submodules => trueto cause bundler to expand any submodules included in the git repository
If a git repository contains multiple
represents a gem located at the same place in the file system as
|~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
the context of the directory in which it is located.
You can specify that a gem is located in a particular location
on the file system. Relative paths are resolved relative to the
directory containing the
Similar to the semantics of the
:git option, the
option requires that the directory in question either contains
.gemspec for the gem, or that you specify an explicit
version that bundler should use.
: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
: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
:submodules options may be passed to the
git method, and
all gems in the block will inherit those options.
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 dependencies listed in
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 requirement on your project (
=> '.'). 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
gemspec method supports optional
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.
When attempting to locate a gem to satisfy a gem requirement, bundler uses the following priority order:
- The source explicitly attached to the gem (using
- 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
- The sources specified via
source, searching each source in your
Gemfilefrom last added to first added.