AnsibleModule

AnsibleModule is a Ruby class that provides basic functionalities as an Ansible module.

It is distributed as a gem package under the MIT-LICENSE.

Installation

Manual Installation

Install Ruby (2.0 or later) and ansible_module gem on your remote hosts.

The following is a typical procedure on Ubuntu Server 14.04:

$ sudo add-apt-repository -y ppa:brightbox/ruby-ng
$ sudo apt-get update
$ sudo apt-get -y install ruby2.1
$ sudo gem install ansible_module

Installation with Ansible

Create an Ansible playbook to install Ruby and ansible_module gem.

The following is an example for Ubuntu Server 14.04:

- hosts: servers
  sudo: yes
  tasks:
  - name: Add ppa for ruby
    apt_repository: repo='ppa:brightbox/ruby-ng' state=present
  - name: Install ruby 2.1
    apt: name=ruby2.1 state=present
  - name: Install ansible_module gem
    gem: name=ansible_module user_install=false state=present

If you named this file ruby_environment.yml, then run the following command on your local host:

$ ansible-playbook -i hosts ruby_environment.yml

In the above example, the hosts file is an inventory which lists up host names or IP addresses.

Example (1)

Create a file named calc on the library directory as follows:

#!/usr/bin/ruby

require 'ansible_module'

class Calc < AnsibleModule
  attribute :x, Integer
  attribute :y, Integer, default: 100

  validates :x, presence: true, numericality: { only_integer: true }
  validates :y, numericality: { only_integer: true }

  def main
    sum = x + y

    exit_json(x: x, y: y, sum: sum, changed: true)
  end
end

Calc.instance.run

The values of attributes x and y are set during instantiation process by AnsibleModule.

Note that you can validate them with validates class method derived from ActiveModel.

Then, create a file named calc.yml as follows:

- hosts: servers
  tasks:
  - name: Make a calculation
    calc: x=50 y=50
    register: result
  - debug: >
      msg="sum = {{ result['sum'] }}"

And run the following command on your local host:

$ ansible-playbook -i hosts calc.yml

Example (2)

Create a file named mysql_change_master on the library directory as follows:

#!/usr/bin/ruby

require 'ansible_module'

class MysqlChangeMaster < AnsibleModule
  attribute :host, String
  attribute :port, Integer, default: 3306
  attribute :user, String
  attribute :password, String
  attribute :mysql_root_password, String

  validates :port, inclusion: { in: 0..65535 }

  def main
    statement = %Q{
      STOP SLAVE;
      CHANGE MASTER TO
        MASTER_HOST='#{host}',
        MASTER_PORT=#{port},
        MASTER_USER='#{user}',
        MASTER_PASSWORD='#{password}',
        MASTER_AUTO_POSITION=1;
      START SLAVE;
    }.squish

    command = %Q{
      /usr/bin/mysql -u root -p#{mysql_root_password} -e "#{statement}"
    }.squish

    system(command)

    exit_json(statement: statement, changed: true)
  end
end

MysqlChangeMaster.instance.run

Note that you can use methods added by ActiveSupport like String#squish.

Then, create a file named replication.yml as follows:

- hosts: mysql-slave
  vars_files:
    - shared/secret.yml
  tasks:
  - name: Change master to the db1
    mysql: >
      host="db1"
      user="repl"
      password="{{ mysql_repl_password }}"
      mysql_root_password="{{ mysql_root_password }}"

Next, create a file named secret.yml on the shared directory as follows:

mysql_repl_password: p@ssw0rd
mysql_root_password: p@ssw0rd

Note that you should replace p@ssw0rd with real passwords.

And run the following command on your local host:

$ ansible-playbook -i hosts replication.yml

You might want to encrypt the secret.yml with ansible-vault. In that case, you must add --ask-vault-pass option to the above command:

$ ansible-playbook -i hosts --ask-vault-pass replication.yml

License

AnsibleModule is distributed under the MIT-LICENSE.