Inprovise Fork

This project implements an extension for the Inprovise provisioning tool providing a fork method to the execution contexts of Inprovise scripts allowing scripts to fork off provisioning commands (apply, revert, validate or trigger) for other nodes.

Installation

$ gem install inprovise-fork

Usage

Add the following to (for example) your Inprovise project's rigrc file.

require 'inprovise/fork'

Syntax

fork(mode = :sync).apply('script', 'name'[, 'name'[, ...]][, config={}])
fork(mode = :sync).revert('script', 'name'[, 'name'[, ...]][, config={}])
fork(mode = :sync).validate('script', 'name'[, 'name'[, ...]][, config={}])
fork(mode = :sync).trigger('action', 'name'[, 'name'[, ...]][, config={}])

or

fork(mode = :sync) do
  apply('script', 'name'[, 'name'[, ...]][, config={}])  
end
fork(mode = :sync) do
  revert('script', 'name'[, 'name'[, ...]][, config={}])
end
fork(mode = :sync) do 
  validate('script', 'name'[, 'name'[, ...]][, config={}])
end
fork(mode = :sync) do
  trigger('action', 'name'[, 'name'[, ...]][, config={}])
end

The mode argument can be :sync (default) or :async. With the first the provisioning methods will not return until the provisioning process they kicked off has finished. With the latter the provisioning methods kick off the provisioning process in parallel and return immediately.

The provisioning methods return a reference to the forking execution context allowing provisioning methods to be chained like:

fork.apply('script', 'node1').trigger('action', 'node1')

Example

By combining the Inprovise-VBox plugin and the Inprovise-Fork plugin provisioning scripts could add a virtual machine on a host server, register an Inprovise node and provision that new node with a single rig command using a scheme like this:

# assumes rigrc has been defined with
# require 'inprovise/vbox' and
# require 'inprovise/fork'

include 'rubysetup.rb'  # includes a scheme defining scripts to control ruby provisioning dependencies

script 'vmSetup' do

  validate do
    # check node setup
    trigger 'gem:exists', 'rails'
  end

  apply do
    trigger 'gem:install', 'rails'
  end

  revert do
    trigger 'gem:uninstall', 'rails'
  end

end


vbox 'myVM' do
    configuration ({
      :name => 'MyVM',
      :image => '/remote/image/path/MyVM.qcow2',
      :memory => 1024,
      :cpus => 2  
    })

    apply do
      fork(:async).apply('vmSetup', 'MyVM')
    end

    revert do
      # in real life you may not want to do this to be able to reinstate 
      # the VM faster with all setup already in place   
      fork(:sync).revert('vmSetup', 'MyVM')
    end
end

end