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.
Global Sources (#source)
At the top of the
Gemfile, add a line for the
Rubygems source that contains
the gems listed in the
It is possible, but not recommended as of Bundler 1.7, to add multiple global
source lines. Each of these
MUST be a valid Rubygems repository.
Sources are checked for gems following the heuristics described in
SOURCE PRIORITY. If a gem is found in more than one global source, Bundler
will print a warning after installing the gem indicating which source was used,
and listing the other sources where the gem is available. A specific source can
be selected for gems that need to use a non-standard repository, suppressing
this warning, by using the
:source option or a
Some gem sources require a username and password. Use
bundle config to set
the username and password for any sources that need it. The command must be run
once on each computer that will install the Gemfile, but this keeps the
credentials from being stored in plain text in version control.
bundle config https://gems.example.com/ user:password
For some sources, like a company Gemfury account, it may be easier to simply include the credentials in the Gemfile as part of the source URL.
Credentials in the source URL will take precedence over credentials set using
If your application requires a specific Ruby version or engine, specify your
requirements using the
ruby method, with the following arguments.
All parameters are
OPTIONAL unless otherwise specified.
The version of Ruby that your application requires. If your application requires an alternate Ruby engine, such as JRuby or Rubinius, this should be the Ruby version that the engine is compatible with.
Each application may specify a Ruby engine. If an engine is specified, an engine version must also be specified.
Engine Version (:engine_version)
Each application may specify a Ruby engine version. If an engine version is specified, an engine must also be specified. If the engine is "ruby" the engine version specified must match the Ruby version.
ruby "1.8.7", :engine => "jruby", :engine_version => "1.6.7"
Each application may specify a Ruby patchlevel.
ruby "2.0.0", :patchlevel => "247"
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 files that should be used when autorequiring via
Bundler.require. You may pass an array with multiple files or
true if file
required has same name as gem or
prevent any file from being autorequired.
gem "redis", :require => ["redis/connection/hiredis", "redis"] gem "webmock", :require => false gem "debugger", :require => true
The argument defaults to the name of the gem. For example, these are identical:
gem "nokogiri" gem "nokogiri", :require => "nokogiri" gem "nokogiri", :require => true
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.
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 32 bit 'mingw32' platform (aka RubyInstaller)
- Windows 64 bit 'mingw32' platform (aka RubyInstaller x64)
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.
You can select an alternate Rubygems repository for a gem using the ':source' option.
gem "some_internal_gem", :source => "https://gems.example.com"
This forces the gem to be loaded from this source and ignores any global sources declared at the top level of the file. If the gem does not exist in this source, it will not be installed.
Bundler will search for child dependencies of this gem by first looking in the source selected for the parent, but if they are not found there, it will fall back on global sources using the ordering described in SOURCE PRIORITY.
Selecting a specific source repository this way also suppresses the ambiguous gem warning described above in GLOBAL SOURCES (#source).
If necessary, you can specify that a gem is located at a particular
git repository. The repository can be public (
or private (
firstname.lastname@example.org: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
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.
If the git repository you want to use is hosted on GitHub and is public, you can use the :github shorthand to specify just the github username and repository name (without the trailing ".git"), separated by a slash. If both the username and repository name are the same, you can omit one.
gem "rails", :github => "rails/rails" gem "rails", :github => "rails"
Are both equivalent to
gem "rails", :git => "git://github.com/rails/rails.git"
In addition, if you wish to choose a specific branch:
gem "rails", :github => "rails/rails", :branch => "branch_name"
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 Source, Git, Path, Group And Platforms
:platforms options may be
applied to a group of gems by using block form.
source "https://gems.example.com" do gem "some_internal_gem" gem "another_internal_gem" end git "git://github.com/rails/rails.git" do gem "activesupport" gem "actionpack" end platforms :ruby do gem "ruby-debug" gem "sqlite3" 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 source, git, or path
repository declared on the parent. This results in bundler prioritizing the
ActiveSupport gem from the Rails git repository over ones from
- The sources specified via global
sourcelines, searching each source in your
Gemfilefrom last added to first added.