Puppet containment example

config.pp

class myclass::config {
  # get the $config from the main class
  # and assignto local scope variable
  $config = $myclass::config
  
  file { $config:
    ensure => present,
  }
}

init.pp

class myclass (
  $package = $::myclas::params::package,
  $config  = $::myclas::params::config,
  $service = $::myclas::params::service,
) inherits myclass::params {

  # contain here ensures that when you do something like
  # file { 'blah':
  #   ensure  => file,
  #   require => Class['myclass'],
  # }
  # then all the resources from these subclasses will
  # be enforce BEFORE File['blah']
  contain myclass::package
  contain myclass::config
  contain myclass::service
  
  # contain doesn't establish order between the subclasses, so we do that here
  Class['myclass::package'] -> Class['myclass::config'] ~> Class['myclass::service']
}

package.pp

class myclass::package {
  # get the $package from the main class
  # and assignto local scope variable
  $package = $myclass::package
  
  package { $package:
    ensure => present,
  }
}

params.pp

class myclass::params (
  case $::facts['os']['family'] {
    'RedHat': {
      $package = 'value for RHEL'
      $config  = 'value for RHEL'
      $service = 'value for RHEL'
    }
    'Debian':  {
      $package = 'value for Debian'
      $config  = 'value for Debian'
      $service = 'value for Debian'
    }
    'Windows':  {
      $package = 'value for Windows'
      $config  = 'value for Windows'
      $service = 'value for Windows'
    }
    default: {
      fail("Module ${module_name} is not supported on ${::facts['os']['name']}")
    }
  }
}

service.pp

class myclass::service {
  # get the $config from the main class
  # and assignto local scope variable
  $service = $myclass::service
  
  service { $service:
    ensure => running,
    enable => true,
  }
}