Lightweight resource provider (LWRP) provides an option of extending the list of available resources by extending it features and allows Chef user to create custom resources.
By creating custom resources one can simply write cookbooks because one can own enriched custom resources using Chef DSL which helps in making the recipe code more expressive.
In Chef community, many of the custom resources are implemented using LWRPs. There are many working examples of LWRP such as iptables_rules and apt_repository.

Working Method

Make sure one has cookbook name Testing_resource and a run_list of node which contains Testing_resource cookbook.

Building LWRP

Step 1 − Create a custom resource in Testing_resource cookbook.
vipin@laptop:~/chef-repo $ subl cookbooks/Testing_resource/resources/default.rb
actions :create, :remove
attribute :title, kind_of: String, default: "World"
attribute :path, kind_of: String, default: "/tmp/greeting.txt"
Step 2 − Create a provider for resources in Tesing_resource cookbook.
vipin@laptop:~/chef-repo $ subl cookbooks/Testing_resource/provider/default.rb
action :create do
log "Adding '#{new_resource.name}' greeting as #{new_resource.
path}"
file new_resource.path do
content "#{new_resource.name}, #{new_resource.title}!"
action :create
end
action :remove do
Chef::Log.info "Removing '#{new_resource.name}' greeting #{new_resource.path}"
file new_resource.path do
action :delete
end
end
Step 3 − Use a new resource by editing Testing_resource default recipe.
vipin@laptop:~/chef-repo $ subl cookbooks/Tesing_resource/recipes/default.rb
greeting "Ohai" do
title "Chef"
action :create
end
Step 4 − Upload the modified cookbook to Chef server.
vipin@laptop:~/chef-repo $ knife cookbook upload greeting
Uploading greeting [0.1.0]
Step 5 − Run Chef-Client on the node.
vipin@server:~$ sudo chef-client
...TRUNCATED OUTPUT...
2013-06-28T21:32:54+00:00] INFO: Processing greeting[Ohai] action
create (greeting::default line 9)
[2013-06-28T21:32:54+00:00] INFO: Adding 'Ohai' greeting as /tmp/
greeting.txt
[2013-06-28T21:32:54+00:00] INFO: Processing file[/tmp/greeting.
txt] action create (/srv/chef/file_store/cookbooks/greeting/
providers/default.rb line 7)
[2013-06-28T21:32:54+00:00] INFO: entered create
[2013-06-28T21:32:54+00:00] INFO: file[/tmp/greeting.txt] created
file /tmp/greeting.txt
...TRUNCATED OUTPUT...
Step 6 − Validate the content of the generated file.
user@server:~$ cat /tmp/greeting.txt
Ohai, Chef!

Workflow Scripts

LWRPs live in cookbooks. A custom resource lives inside the cookbooks, and will be available under the cookbook name. In the workflow, first we define the definitions and then pass the attributes to the resources which is going to be used in the cookbook. Finally, we use those actions and attributes in our recipe.

Chef – Blueprints

In Chef, blueprints are the tools to find out and record exactly what is present on the server. Blueprints record all the things required such as directors, packages, configuration files, and so on. Blueprints have the capability to split server information in various formats. One of them is Chef recipe. This helps to configure unique server using Chef.

Woring Method

We need to have Python and Git installed on the node where we need to run the blueprint.
Step 1 − Install the blueprint.
vipin@server:~$ pip install blueprint
Step 2 − Create a blueprint.
user@server:~$ sudo blueprint create internal-cookbook
# [blueprint] using cached blueprintignore(5) rules
# [blueprint] searching for Python packages
# [blueprint] searching for PEAR/PECL packages
# [blueprint] searching for Yum packages
# [blueprint] searching for Ruby gems
# [blueprint] searching for npm packages
# [blueprint] searching for software built from source
# [blueprint] searching for configuration files
# [blueprint] /etc/ssl/certs/AC_Ra\xc3\xadz_Certic\xc3\
xa1mara_S.A..pem not UTF-8 - skipping it
# [blueprint] /etc/ssl/certs/NetLock_Arany_=Class_Gold=_F\xc5\
x91tan\xc3\xbas\xc3\xadtv\xc3\xa1ny.pem not UTF-8 - skipping it
# [blueprint] /etc/ssl/certs/EBG_Elektronik_Sertifika_Hizmet_Sa\
xc4\x9flay\xc4\xb1c\xc4\xb1s\xc4\xb1.pem not UTF-8 - skipping it
# [blueprint] /etc/ssl/certs/Certinomis_-_Autorit\xc3\xa9_Racine.
pem not UTF-8 - skipping it
# [blueprint] /etc/ssl/certs/T\xc3\x9cB\xc4\xb0TAK_UEKAE_K\xc3\
xb6k_Sertifika_Hizmet_Sa\xc4\x9flay\xc4\xb1c\xc4\xb1s\xc4\xb1_-_S\
xc3\xbcr\xc3\xbcm_3.pem not UTF-8 - skipping it
# [blueprint] searching for APT packages
# [blueprint] searching for service dependencies
Step 3 − Create a cookbook from the blueprint.
user@server:~$ blueprint show -C internal-cookbook my-server/recipes/default.rb
Step 4 − Validate the content of the generated file.
user@server:~$ cat internal-cookbook /recipes/default.rb
#
# Automatically generated by blueprint(7). Edit at your own risk.
#
cookbook_file('/tmp/96468fd1cc36927a027045b223c61065de6bc575.tar')
do
backup false
group 'root'
mode '0644'
owner 'root'
source 'tmp/96468fd1cc36927a027045b223c61065de6bc575.tar'
end
execute('/tmp/96468fd1cc36927a027045b223c61065de6bc575.tar') do
command 'tar xf "/tmp/96468fd1cc36927a027045b223c61065de6bc575.tar"'
cwd '/usr/local'
end
directory('/etc/apt/apt.conf.d') do
...TRUNCATED OUTPUT...
service('ssh') do
action [:enable, :start]
subscribes :restart, resources('cookbook_file[/etc/default/
keyboard]', 'cookbook_file[/etc/default/console-setup]',
'cookbook_file[/etc/default/ntfs-3g]', 'package[openssh-server]',
'execute[96468fd1cc36927a027045b223c61065de6bc575.tar]')
end

Workflow Script

Blueprint is a Python package that finds out all the relevant configuration data of the server and stores it in a Git repo. Each blueprint has its own name.
One can ask the blueprint to show the content of its Git repo in various formants.
user@server:~$ ls -l internal-cookbook /
total 8
drwxrwxr-x 3 vagrant vagrant 4096 Jun 28 06:01 files
-rw-rw-r– 1 vagrant vagrant 0 Jun 28 06:01 metadata.rb
drwxrwxr-x 2 vagrant vagrant 4096 Jun 28 06:01 recipes

Blueprints Show Commands

user@server:~$ blueprint show-packages my-server
...TRUNCATED OUTPUT...
apt wireless-regdb 2011.04.28-1ubuntu3
apt zlib1g-dev 1:1.2.3.4.dfsg-3ubuntu4
python2.7 distribute 0.6.45
python2.7 pip 1.3.1
pip blueprint 3.4.2
pip virtualenv 1.9.1

The preceding command shows all kinds of installed packages. Other show commands are as follows −
• show-files
• show-services
• show-sources

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