optionally passing a parameter to puppet resource -

is there way pass parameter puppet resource if it's been set? example, have manifest creates new user, , may or may not want set uid , gid manually. best way can think this:

class example (     $uid      = undef,     $gid      = undef,     $username = 'default' ) {     user { $username:         ensure => present,         # etc     }      if $uid != undef {         user { "uid-${username}":             name    => $username,             uid     => $uid,             require => user[$username]         }     }      if $gid != undef {         user { "gid-${username}":             name    => $username,             gid     => $gid,             require => user[$username]         }     } } 

but lot of code determine whether or not send uid and/or gid. there better way?

i think example fail compile due multiple declarations, because name on user resource being checked uniqueness. being said, there couple ways make better in opinion.

the first way involves attribute amending:

... user { $username:     ensure => present,     # etc }  if $uid != undef {     user[$username] { uid => $uid } }  if $gid != undef {     user[$username] { gid => $gid } } 

the second involves setting attributes hash:

class example (     hash $id         = {},     string $username = 'default' ) {     user { $username:         ensure => present,         *      => $id,         # etc     } } 

and either passing additional parameters in via declaration:

class example { 'foo':   username => 'bar',   id       => { uid => 1000, gid => 1000 } } 

or using automatic hiera lookups similar to:

example::id:   uid: 1000   gid: 1000 

note not specifying id in either case (declaration or hiera) still result in correct , expected behavior of user resource without uid or gid altered.

you can find both methods documented @ https://docs.puppet.com/puppet/latest/reference/lang_resources_advanced.html, , may able figure out method or 2 document.