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.
GLOBAL SOURCES
At the top of the Gemfile, add a line for the Rubygems source that con‐
tains the gems listed in the Gemfile.
source "https://rubygems.org"
It is possible, but not recommended as of Bundler 1.7, to add multiple
global source lines. Each of these sources 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 avail‐
able. 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 source block.
CREDENTIALS
Some gem sources require a username and password. Use bundle config(1)
bundle-config.1.html to set the username and password for any of the
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 gems.example.com user:password
For some sources, like a company Gemfury account, it may be easier to
include the credentials in the Gemfile as part of the source URL.
source "https://user:password@gems.example.com"
Credentials in the source URL will take precedence over credentials set
using config.
RUBY
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.
VERSION (required)
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.
ruby "1.9.3"
ENGINE
Each application may specify a Ruby engine. If an engine is specified,
an engine version must also be specified.
ENGINE VERSION
Each application may specify a Ruby engine version. If an engine ver‐
sion 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"
PATCHLEVEL
Each application may specify a Ruby patchlevel.
ruby "2.0.0", :patchlevel => "247"
GEMS
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
Each gem MAY specify files that should be used when autorequiring via
Bundler.require. You may pass an array with multiple files or true if
file you want required has same name as gem or false to 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
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 the _default_ group
Bundler.require(:default) # identical
Bundler.require(:default, :test) # requires the _default_ and _test_ groups
Bundler.require(:test) # requires 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 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://bundler.io/rationale.html.
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
mri Same as ruby, but not Rubinius
mingw Windows 32 bit ´mingw32´ platform (aka RubyInstaller)
x64_mingw
Windows 64 bit ´mingw32´ platform (aka RubyInstaller x64)
rbx Same as ruby, but only Rubinius (not MRI)
jruby JRuby
mswin Windows
You can restrict further by platform and version for all platforms
except for rbx, jruby, and mswin.
To specify a version in addition to a platform, append the version num‐
ber without the delimiter to the platform. For example, to specify that
a gem should only be used on platforms with Ruby 2.3, use:
ruby_23
The full list of platforms and supported versions includes:
ruby 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5
mri 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5
mingw 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5
x64_mingw
2.0, 2.1, 2.2, 2.3, 2.4, 2.5
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.
SOURCE
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).
GIT
If necessary, you can specify that a gem is located at a particular git
repository using the :git parameter. The repository can be accessed via
several protocols:
HTTP(S)
gem "rails", :git => "https://github.com/rails/rails.git"
SSH gem "rails", :git => "git@github.com:rails/rails.git"
git gem "rails", :git => "git://github.com/rails/rails.git"
If using SSH, the user that you use to run bundle install MUST have the
appropriate keys available in their $HOME/.ssh.
NOTE: http:// and git:// URLs should be avoided if at all possible.
These protocols are unauthenticated, so a man-in-the-middle attacker
can deliver malicious code and compromise your system. HTTPS and SSH
are strongly preferred.
The group, platforms, and require options are available and behave
exactly the same as they would for a normal gem.
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.
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 => "https://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.
GIT SOURCE
A custom git source can be defined via the git_source method. Provide
the source´s name as an argument, and a block which receives a single
argument and interpolates it into a string to return the full repo
address:
git_source(:stash){ |repo_name| "https://stash.corp.acme.pl/#{repo_name}.git" }
gem ´rails´, :stash => ´forks/rails´
In addition, if you wish to choose a specific branch:
gem "rails", :stash => "forks/rails", :branch => "branch_name"
GITHUB
NOTE: This shorthand should be avoided until Bundler 2.0, since it cur‐
rently expands to an insecure git:// URL. This allows a man-in-the-mid‐
dle attacker to compromise your system.
If the git repository you want to use is hosted on GitHub and is pub‐
lic, you can use the :github shorthand to specify 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"
Since the github method is a specialization of git_source, it accepts a
:branch named argument.
GIST
If the git repository you want to use is hosted as a Github Gist and is
public, you can use the :gist shorthand to specify the gist identifier
(without the trailing ".git").
gem "the_hatch", :gist => "4815162342"
Is equivalent to:
gem "the_hatch", :git => "https://gist.github.com/4815162342.git"
Since the gist method is a specialization of git_source, it accepts a
:branch named argument.
BITBUCKET
If the git repository you want to use is hosted on Bitbucket and is
public, you can use the :bitbucket shorthand to specify the bitbucket
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", :bitbucket => "rails/rails"
gem "rails", :bitbucket => "rails"
Are both equivalent to
gem "rails", :git => "https://rails@bitbucket.org/rails/rails.git"
Since the bitbucket method is a specialization of git_source, it
accepts a :branch named argument.
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"
If you would like to use multiple local gems directly from the filesys‐
tem, you can set a global path option to the path containing the gem´s
files. This will automatically load gemspec files from subdirectories.
path ´components´ do
gem ´admin_ui´
gem ´public_ui´
end
BLOCK FORM OF SOURCE, GIT, PATH, GROUP and PLATFORMS
The :source, :git, :path, :group, and :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 "https://github.com/rails/rails.git" do
gem "activesupport"
gem "actionpack"
end
platforms :ruby do
gem "ruby-debug"
gem "sqlite3"
end
group :development, :optional => true do
gem "wirble"
gem "faker"
end
In the case of the group block form the :optional option can be given
to prevent a group from being installed unless listed in the --with
option given to the bundle install command.
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.
INSTALL_IF
The install_if method allows gems to be installed based on a proc or
lambda. This is especially useful for optional gems that can only be
used if certain software is installed or some other conditions are met.
install_if -> { RUBY_PLATFORM =~ /darwin/ } do
gem "pasteboard"
end
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, :glob, :name, and :develop‐
ment_group options, which control where bundler looks for the .gemspec,
the glob it uses to look for the gemspec (defaults to: "{,,/*}.gem‐
spec"), what named .gemspec it uses (if more than one is present), and
which group development dependencies are included in.
When a gemspec dependency encounters version conflicts during resolu‐
tion, the local version under development will always be selected --
even if there are remote versions that better match other requirements
for the gemspec gem.
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 :source, :path, or
:git)
2. 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 rubygems.org
3. The sources specified via global source lines, searching each
source in your Gemfile from last added to first added.
July 2017 GEMFILE(5)
