if $puppet_interval {
  $action = 'set'
} else {
  $action = 'del'
}

augeas { 'puppet.conf':
    context => '/files/etc/puppet.conf',
    changes => [
      "set agent/server $::servername",
      "set agent/environment $::environment",
      "${action}  agent/runinterval $puppet_interval",
    ],
    requires => Package['puppet'],
    notify => Service['puppet'],
  }