1. Description - What this utility does and why it is useful
2. Setup - The basics of getting started with Puppet Module Gems
   • Setup requirements
3. Usage - Configuration options and additional functionality
4. Reference - An under-the-hood peek at what the module is doing and how
5. Limitations - OS compatibility, etc.
6. Support

Puppet Module Gems is a utility that generates gemspecs and builds management gems based on a YAML-based configuration. The purpose for these gems is to reduce the amount of changes required to sync shared dependencies across multiple modules’ Gemfiles.

For example, when a dependency gem publishes a new release that requires Ruby 2.3.3, this would normally break all modules that install this gem that run on a version of Ruby less than 2.3.3. To fix this previously, you would need a modulesync to pin the gem to a compatible version. With these new gem management gems, you can instead update the gem version pin in a configuration YAML. The gem management will then build and publish to rubygems, and a bundle update fixes all affected modules.

• Requires Ruby version 2.0 or greater
• Requires RubyGems gem version 2.0 or greater
• Requires Bundler gem version 1.3.0 or greater

To get started using this utility, first clone this git repository:

git clone [email protected]:puppetlabs/puppet-module-gems.git

Install the development gems:

bundle install

To build the gems with the default configuration, execute the script bundle exec exe/build-gems.rb. The gemspec files and gems will be generated in the pkg directory. Use the push-gems.rb from the same location to push to rubygems.org, if you are a maintainer.

To build customized dependency gems, you simply need to modify the config yamls prior to running the script.

First modify the config/info.yml to customize the prefix for your gem names, in addition to the rest of the required information. Secondly, you will need to modify the config/dependencies.yml to customize the dependency matrix to suit your needs. After defining these customizations, you can build your gems with the directions detailed in Building the gems.

To use the resulting gems, replace the sections of the Module Gemfile with the appropriate gems and conditions.

For Example:

group :development do
  gem 'puppet-lint',                        :require => false
  gem 'metadata-json-lint',                 :require => false, :platforms => 'ruby'
  gem 'puppet_facts',                       :require => false
  gem 'puppet-blacksmith', '>= 3.4.0',      :require => false, :platforms => 'ruby'
  gem 'puppetlabs_spec_helper', '>= 1.2.1', :require => false
  gem 'rspec-puppet', '>= 2.3.2',           :require => false
  gem 'rspec-puppet-facts',                 :require => false, :platforms => 'ruby'
  gem 'mocha', '< 1.2.0',                   :require => false
  gem 'simplecov',                          :require => false, :platforms => 'ruby'
  gem 'rubocop',                            :require => false
  gem 'pry',                                :require => false
  gem 'rainbow', '< 2.2.0',                 :require => false
end

group :system_tests do
  gem 'beaker-puppet_install_helper',                                            :require => false
  gem 'beaker-module_install_helper',                                            :require => false
  gem 'master_manipulator',                                                      :require => false
end

The above Gemfile section would become:

# calculate the correct package names from the current ruby version
ruby_version_segments = Gem::Version.new(RUBY_VERSION.dup).segments
minor_version = "#{ruby_version_segments[0]}.#{ruby_version_segments[1]}"

gem "puppet-module-posix-default-r#{minor_version}"

group :development do
  gem "puppet-module-posix-dev-r#{minor_version}"
end

group :system_tests do
  gem "puppet-module-posix-system-r#{minor_version}"
end

After this update, the subsequent bundle install or bundle update would pull in the new gems and the dependencies should reflect the correct version bindings based on the Ruby version. Any future gems and version pinning that may be needed can be done via publishing updated management gems.

Reserved Keys

• info - Details the start of the information block. Required.
• prefix - Indicates the prefix to use for the generated gems. Required.

Required Keys

• authors - String. The author of these gems.
• email - String. Email address of the author.
• homepage - String. Homepage for the gem project.
• licenses - String. License to publish gems under.
• summary - String. Brief description of what the gem does.
• version - String. Version of these gems.

Reserved Keys

• dependencies - Details the start of the dependencies block. Required.
• shared - Details the shared dependencies amongst the keys within the same tier.
• gem - Details the name of the gem dependency to add. Required.
• version - Details the version bindings for the gem listed in preceding gem.

Example

dependencies:
  shared:
    a:
      - gem: shared-gem
        version: '> 1.0.0'
  first:
    a:
      - gem: a-gem-one
    b:
      - gem: b-gem-one
        version: '< 2.0.0'
  second:
    b:
      - gem: b-gem-two

The above dependency matrix will generate this list of gems if the defined prefix is test-gem with version 1.0.0:

• test-gem-first-a-1.0.0.gem
• test-gem-first-b-1.0.0.gem
• test-gem-second-a-1.0.0.gem
• test-gem-second-b-1.0.0.gem

And for example, the gemspec for test-gem-first-a-1.0.0.gem will include dependencies of:

• shared-gem, '> 1.0.0'
• a-gem-one

Note: To add a version range to a dependency, simply put the lower and upper bindings in an array:

- gem: gem-name
  version: ['>= 1.0.0', '< 2.0.0']

• From a clean checkout of master, create a release prep branch.
• Update config/info.yml with the new version.
• Update CHANGELOG.md.
• PR the release prep.
• Once PR is merged, checkout a clean copy of master.
• Run bundle exec exe/build-gems.rb to build the gems into the pkg directory.
• Validate that the gems have build correctly. The next step requires that you have Ownership permissions for these gems on rubygems.org, also requires access to internal Puppet network.
• Run bundle exec exe/push-gems.rb to update owners and publish to rubygems.org.
• Tag the version and push tags to github.
  • e.g. git tag -a 0.1.2 -m "0.1.2"
  • e.g. git push upstream --tags

• Check out a clean copy from master.
• Run bundle exec exe/build-gems.rb to build the gems into the pkg directory.
• Confirm pkg directory contains a variety of .gem and .gemspec files.
• Locate a module that is making use of puppet-module-gems.
• Edit the Gemfile and point the gems to the local copy of your gems.

Example

group :development do
  gem "puppet-module-posix-default-r#{minor_version}",    :require => false, :platforms => "ruby", :path => '/Users/paula/workspace/puppet-module-gems/pkg/'
  gem "puppet-module-win-default-r#{minor_version}",      :require => false, :platforms => ["mswin", "mingw", "x64_mingw"], :path => '/Users/paula/workspace/puppet-module-gems/pkg/'
  gem "puppet-module-posix-dev-r#{minor_version}",        :require => false, :platforms => "ruby", :path => '/Users/paula/workspace/puppet-module-gems/pkg/'
  gem "puppet-module-win-dev-r#{minor_version}", '0.0.7', :require => false, :platforms => ["mswin", "mingw", "x64_mingw"], :path => '/Users/paula/workspace/puppet-module-gems/pkg/'
  gem "json_pure", '<= 2.0.1',                            :require => false if Gem::Version.new(RUBY_VERSION.dup) < Gem::Version.new('2.0.0')
  gem "fast_gettext", '1.1.0',                            :require => false if Gem::Version.new(RUBY_VERSION.dup) < Gem::Version.new('2.1.0')
  gem "fast_gettext",                                     :require => false if Gem::Version.new(RUBY_VERSION.dup) >= Gem::Version.new('2.1.0')
end

• Ensure the Gemfile is generated as expected by running bundle install --path .bundle/gems/

## Testing changes on a bigger scale

To test potentially harmful changes with a module on travis / appveyor / another build system. You can use a third party gem repository.

• bump your version of config.info to something higher than the current release
• make your changes in puppet-module-gems
• build your packages
• open your gemfury account and upload the gems ie https://manage.fury.io/dashboard/
• Update the module and edit its gemfile to point at gemfury

source 'https://<token>@gem.fury.io/<user>/'
gem "puppet-module-posix-system-r#{minor_version}", require: false, platforms: [:ruby], :source => "https://<token>@gem.fury.io/<user>/"

NB remember to use your actual token.

• test locally, then create your pr for the module.
• check travis / appveyor / build system for your pass / fails.

Use of this utility has only been tested on Linux and OS-X platforms.

This utility is maintained and developed by the Puppet SDK and Puppet Modules team. Please file an issue for support. Contributions are also welcomed!