Ruby

Chef Sugar

Chef Sugar is a Gem & Chef Recipe that includes series of helpful syntactic sugars on top of the Chef core and other resources to make a cleaner, more lean recipe DSL, enforce DRY principles, and make writing Chef recipes an awesome and fun experience!

Requirements

Platforms

• any platform

Chef

• Chef 13.0+

Cookbooks

• none

Installation

If you want to develop/hack on chef-sugar, please see the CONTRIBUTING.md.

If you are using Berkshelf, add chef-sugar to your Berksfile:

cookbook 'chef-sugar'

Otherwise, you can use knife or download the tarball directly from the community site:

knife cookbook site install chef-sugar

Usage

Simply depend on this cookbook in the metadata of your cookbook and the gem will be installed and required..

Requiring the Chef Sugar Gem will automatically extend the Recipe DSL, Chef::Resource, and Chef::Provider with helpful convenience methods.

Module Method

If you are working outside of the Recipe DSL, you can use the module methods instead of the Recipe DSL. In general, the module methods have the same name as their Recipe-DSL counterparts, but require the node object as a parameter. For example:

In a Recipe:

# cookbook/recipes/default.rb
do_something if windows?

In a Library as a singleton:

# cookbook/libraries/default.rb
def only_on_windows(&block)
  yield if Chef::Sugar::PlatformFamily.windows?(@node)
end

In a Library as a Mixin:

# cookbook/libraries/default.rb
include Chef::Sugar::PlatformFamily

def only_on_windows(&block)
  yield if windows?(@node)
end

API

Note: For the most extensive API documentation, please see the YARD documentation.

Architecture

Note: Some of the architecture commands begin with an underscore (_) because Ruby does not permit methods to start with a numeric.

• _64_bit?
• _32_bit?
• intel?
• sparc?
• ppc64?
• ppc64le?
• powerpc?

Examples

execute 'build[my binary]' do
  command '...'
  not_if  { _64_bit? }
end

Cloud

• azure?
• cloud?
• digitalocean?
• ec2?
• eucalyptus?
• gce?
• linode?
• openstack?
• cloudstack?
• rackspace?
• softlayer?

Examples

template '/tmp/config' do
  variables(
    # See also: best_ip_for
    ipaddress: cloud? ? node['local_ipv4'] : node['public_ipv4']
  )
end

Core Extensions

Note: Core extensions are not included by default. You must require the chef/sugar/core_extensions module manually to gain access to these APIs:

require 'chef/sugar/core_extensions'

• String#satisfies?
• String#satisfied_by?
• Array#satisfied_by?
• Object#blank?

Examples

# Checking version constraints
'1.0.0'.satisfies?('~> 1.0') #=> true
'~> 1.0'.satisfied_by?('1.0') #=> true

# Check for an object's presence
''.blank? #=> true
['hello'].blank? #=> false

Data Bag

• encrypted_data_bag_item - a handy DSL method for loading encrypted data bag items the same way you load a regular data bag item; this requires Chef::Config[:encrypted_data_bag_secret] is set!
• encrypted_data_bag_item_for_environment - find the encrypted data bag entry for the current node's Chef environment.
• data_bag_item_for_environment - find the data bag entry for the current node's Chef environment.

Examples

encrypted_data_bag_item('accounts', 'hipchat')

encrypted_data_bag_item_for_environment('accounts', 'github')

data_bag_item_for_environment('accounts', 'github')

Docker

Chef Sugar looks for hints to see if the node being converged is a Docker container. When Ohai supports checking other nodes, Chef Sugar will automatically pick up the information.

• docker?

Examples

template '/runme' do
  only_if { docker?(node) }
end

Attributes

Chef Sugar adds more Chef-like DSL to attribute definitions. Instead of using the Ruby hash syntax, you can define attributes using nested namespaces. This DSL may be more friendly to non-Ruby developers. It can safely be mixed-and-matched with the standard syntax.

# This is functionally the same as default['apache2']['config']['root'] = '/var/www'
namespace 'apache2' do
  namespace 'config' do
    root '/var/www'
  end
end

# Specify multiple keys instead of nesting namespaces
namespace 'apache2', 'config' do
  root '/var/www'
end

# Specify different nested precedence levels
namespace 'apache2', precedence: normal do
  namespace 'config', precedence: override do
    root '/var/www' #=> override['apache2']['config']['root'] = '/var/www'
  end
end

Constraints

• constraints - create a new constraint (or requirement) that can be used to test version validations.
• chef_version - (DSL only) a wrapper for version(Chef::VERSION)
• version - create a new version that can be used to test constraint validation.

Examples

# Check if a version is satisfied by a constraint
version('1.2.3').satisfies?('~> 1.2.0')

# Check if a constraint is satisfied by a version
constraint('~> 1.2.0').satisfied_by?('1.2.3')

# Support multiple constraints
version('1.2.3').satisfies?('> 1.2', '< 2.0')
constraint('> 1.2', '< 2.0').satisfied_by?('1.2.3')

# Only perform an operation if Chef is at a certain version
package 'apache2' do
  not_if { chef_version.satisfies?('~> 11.0') } # Ignore Chef 11
end

Kernel

• require_chef_gem - "safely" require a gem. Loading a gem with Chef is sometimes difficult and confusing. The errors that Chef produces are also sometimes not very intuitive. In the event you require a gem to exist on the system, you can use require_chef_gem, which will attempt to require the gem and then produce helpful output if the gem is not installed:

    Chef could not load the gem `#{name}'! You may need to install the gem
    manually with `gem install #{name}', or include a recipe before you can
    use this resource. Please consult the documentation for this cookbook
    for proper usage.
  

Examples

# LWRP
require_chef_gem 'pry'

class Chef
  class Provider
    class MyProvider > Provider
      require_chef_gem 'pry'
    end
  end
end

Init

• systemd? - detect if init system is systemd
• upstart? - detect if init system is upstart
• runit? - detect if init system is runit

Examples

systemd_service 'my-service' do
  description 'My Service'
  install do
    wanted_by 'multi-user.target'
  end
  service do
    exec_start '/usr/bin/myserviced'
  end
  action [:create, :enable, :start]
  only_if { systemd? }
end

cookbook_file '/etc/init/my-service.conf' do
  source 'my-service.conf'
  only_if { upstart? }
end

IP

• best_ip_for - determine the best IP address for the given "other" node, preferring local IP addresses over public ones.

Examples

redis = search('node', 'role:redis').first

template '/tmp/config' do
  variables(
    ipaddress: best_ip_for(redis)
  )
end

Node

Additional methods for the node object

• deep_fetch - safely fetch a nested attribute.
• deep_fetch! - fetch a nested attribute, raising a more semantic error if the key does not exist.
• in? - determine if the node is in the given Chef environment.

Examples

credentials = if node.in?('production')
                Chef::EncryptedDataBag.new('...')
              else
                data_bag('...')
              end

node.deep_fetch('apache2', 'config', 'root') => node['apache2']['config']['root']

Platform

• amazon_linux?
• centos?
• linux_mint?
• oracle_linux?
• redhat_enterprise_linux?
• scientific_linux?
• ubuntu?
• solaris2?
• aix?
• smartos?
• omnios?
• raspbian?
• nexus?
• ios_xr?

There are also a series of dynamically defined matchers that map named operating system release versions and comparison operators in the form "#{platform}#{operator}#{name}?". For example:

• debian_after_squeeze?
• linuxmint_after_or_at_olivia?
• mac_os_x_lion?
• centos_final?
• ubuntu_before_lucid?
• ubuntu_before_or_at_maverick?
• solaris_10?
• solaris_11?

To get a full list, run the following in IRB:

require 'chef/sugar'
puts Chef::Sugar::Platform.instance_methods

Examples

if ubuntu?
  execute 'apt-get update'
end

Platform Family

• arch_linux?
• debian?
• fedora?
• freebsd?
• gentoo?
• linux?
• mac_os_x?
• openbsd?
• rhel?
• slackware?
• suse?
• windows?
• wrlinux?

Examples

node['attribute'] = if windows?
                      'C:\Foo\BarDrive'
                    else
                      '/foo/bar_drive'
                    end

Ruby

Note: The applies to the Ruby found at node['languages']['ruby'].

• ruby_20?
• ruby_19?

Examples

log 'This has been known to fail on Ruby 2.0' if ruby_20?

Run Context

• includes_recipe? - determines if the current run context includes the recipe

if includes_recipe?('apache2::default')
  apache_module 'my_module' do
    # ...
  end
end

Shell

• which
• dev_null
• installed?
• installed_at_version?
• version_for

Examples

log "Using `mongo` at `#{which('mongo')}`"

if installed?('apt')
  execute 'apt-get update'
end

execute 'install[thing]' do
  command "... 2>&1 #{dev_null}"
  not_if  { installed_at_version?('thing', node['thing']['version']) }
end

log "Skipping git install, version is at #{version_for('mongo', '-v')}"

Vagrant

• vagrant?

Examples

http_request 'http://...' do
  not_if { vagrant? }
end

Virtualization

• kvm?
• lxc?
• parallels?
• virtualbox?
• vmware?
• openvz?

Examples

service 'ntpd' do
  action [:enable, :start]
  not_if { lxc? }
end

Filters

• at_compile_time - accepts a block of resources to run at compile time
• before - insert resource in the collection before the given resource
• after - insert resource in the collection after the given resource

Examples

at_compile_time do
  package 'apache2'
end

# This is equivalent to
package 'apache2' do
  action :nothing
end.run_action(:install)

before 'service[apache2]' do
  log 'I am before the apache 2 service fires!'
end

after 'service[apache2]' do
  log 'I am after the apache 2 service fires!'
end

License & Authors

• Author: Seth Vargo (sethvargo@gmail.com)

Copyright 2013-2015 Seth Vargo

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.