Configuration file manager.

install.yml

:defaults:
  :perm: 644
  :hosts:
    - MyClient1
    - MyClient2

:files:
  - :path: etc/ssh/sshd_config

  - :path: etc/ntp.conf

  - :path: etc/bacula/bacula-fd.conf
    :perm: 640
    :packages: [ bacula-client ]
    :hosts: [ MyClient1, MyClient2 ]

Rakefile

require 'yaml'
require 'open3'
require 'socket'

task :default => [:install]

def command? name
  `which #{name}`
  $?.success?
end

def hostname
  Socket.gethostname
end

def allowed_host? hosts
  return true if hosts.nil?
  hosts.include? hostname
end

def pkg_exists? pkg
  if command? 'pacman'
    Open3.popen3 'pacman', '-qQ', pkg do |_,_,_,wait_thr|
      wait_thr.value.to_i # the exit status
    end
  end
end

def pkgs_exists? pkgs
  return true if pkgs.nil?
  pkgs.map( &method(:pkg_exists?) ).delete_if{ |e| e == 0 }.empty?
end

task :install do
  config = YAML::load File.open('install.yml')
  config[:files].each do |f|
    next unless allowed_host? f[:hosts]
    next unless pkgs_exists? f[:packages]

    perm = f[:perm]
    perm ||= config[:defaults][:perm]

    src = File.expand_path (
      if File.exists? f[:path]
        f[:path]
      else
        base = File.basename( f[:path].chomp( File.extname(f[:path]) ) )
        dir = File.dirname(f[:path])
        "#{dir}/" + Dir.entries(dir).grep(/^#{base}.#{hostname.downcase}/).first
      end
    )

    dest = File.expand_path '/' + f[:path]

    system "sudo cp #{src} #{dest}"
    system "sudo chmod #{perm.to_s} #{dest}"

    p "#{src} -> #{dest}"
  end
end