path: root/man/gemfile.5.txt

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
       associated  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
       contains 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
       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 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,  Rubinius  or
       TruffleRuby, 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.

       What exactly is an Engine? - A Ruby engine is an implementation of  the
       Ruby language.

       o   For  background:  the  reference  or original implementation of the
           Ruby  programming  language  is  called  Matz's  Ruby   Interpreter
           https://en.wikipedia.org/wiki/Ruby_MRI,  or  MRI for short. This is
           named after Ruby creator Yukihiro Matsumoto, also  known  as  Matz.
           MRI  is also known as CRuby, because it is written in C. MRI is the
           most widely used Ruby engine.

       o   Other implementations https://www.ruby-lang.org/en/about/  of  Ruby
           exist. Some of the more well-known implementations include Rubinius
           https://rubinius.com/, and JRuby http://jruby.org/. Rubinius is  an
           alternative  implementation  of  Ruby  written in Ruby. JRuby is an
           implementation of Ruby on the JVM, short for Java Virtual Machine.



   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"



   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
       arguments. 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 "byebug", :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
       bundle install should not install with the without configuration.

       To  specify  multiple  groups  to  ignore,  specify  a  list  of groups
       separated by spaces.



           bundle config set without test
           bundle config set without development test



       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
       versions  of  the  same gems in different groups. For more details, see
       Understanding Bundler https://bundler.io/rationale.html.

   PLATFORMS
       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 platforms.

       There are a number of Gemfile platforms:

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

       mri    Same as ruby, but only C Ruby (MRI)

       mingw  Windows 32 bit 'mingw32' platform (aka RubyInstaller)

       x64_mingw
              Windows 64 bit 'mingw32' platform (aka RubyInstaller x64)

       rbx    Rubinius

       jruby  JRuby

       truffleruby
              TruffleRuby

       mswin  Windows

       You  can  restrict  further  by  platform and version for all platforms
       except for rbx, jruby, truffleruby and mswin.

       To specify a version in addition to  a  platform,  append  the  version
       number  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, 2.6

       mri    1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6

       mingw  1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6

       x64_mingw
              2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6

       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  bundle-install.1.html,
       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).

       Using  the  :source  option  for  an individual gem will also make that
       source available as a possible global source for any other  gems  which
       do  not  specify explicit sources. Thus, when adding gems with explicit
       sources, it is recommended that you also ensure all other gems  in  the
       Gemfile are using explicit sources.

   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
       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 => "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
       version 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". For example:

              gem  "rails",  :git   =>   "https://github.com/rails/rails.git",
              :branch => "5-0-stable"

              gem  "rails", :git => "https://github.com/rails/rails.git", :tag
              => "v5.0.0"

              gem "rails", :git => "https://github.com/rails/rails.git",  :ref
              => "4aded"

       submodules
              For          reference,          a         git         submodule
              https://git-scm.com/book/en/v2/Git-Tools-Submodules   lets   you
              have   another   git  repository  within  a  subfolder  of  your
              repository. Specify :submodules =>  true  to  cause  bundler  to
              expand any submodules included in the git repository

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



           |~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
       currently   expands   to   an   insecure  git://  URL.  This  allows  a
       man-in-the-middle attacker to compromise your system.

       If the git repository you want to  use  is  hosted  on  GitHub  and  is
       public,  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
       containing 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
       filesystem, 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
       :submodules  options  may  be passed to the git method, and all gems in
       the block will inherit those options.

       The presence of a source block in a  Gemfile  also  makes  that  source
       available  as  a possible global source for any other gems which do not
       specify explicit sources. Thus, when  defining  source  blocks,  it  is
       recommended  that  you  also  ensure  all other gems in the Gemfile are
       using explicit sources, either via source blocks or :source  directives
       on individual gems.

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
       The  .gemspec  http://guides.rubygems.org/specification-reference/ file
       is where you provide metadata about your gem to Rubygems. Some required
       Gemspec  attributes include the name, description, and homepage of your
       gem. This is also where you specify the dependencies your gem needs  to
       run.

       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 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
       requirement 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
       :development_group  options,  which control where bundler looks for the
       .gemspec, the glob it uses  to  look  for  the  gemspec  (defaults  to:
       "{,,/*}.gemspec"),  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
       resolution, 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 2020                        GEMFILE(5)