How do I make puppet copy a file only if source exists? - vagrant

Question

I am trying to provision a vagrant VM to allow users to supply their own bash_profile.local but I don't want this file tracked in the vm's vcs repo. I have a tracked bash_profile.local.dist file that they can rename. How can I tell puppet to only create a file if the source file exists? It is currently working correctly but logs an error during provisioning and this is what I'm trying to avoid.
This is the manifest:
class local
{
file { '.bash_profile.local':
source => 'puppet:///modules/local/bash_profile.local',
path => '/home/vagrant/.bash_profile.local',
replace => false,
mode => 0644,
owner => 'vagrant',
group => 'vagrant',
}
}

Answer 1

You could abuse file in this way :
$a = file('/etc/puppet/modules/local/files/bash_profile.local','/dev/null')
if($a != '') {
file { '.bash_profile.local':
content => $a,
...
}
}

Answer 2

This is not exactly what you asked but you can supply multiple paths in the source, so you can have a default empty file if the user didn't supplied his own.
class local
{
file { '.bash_profile.local':
source => [
'puppet:///modules/local/bash_profile.local',
'puppet:///modules/local/bash_profile.local.default'
],
path => '/home/vagrant/.bash_profile.local',
replace => false,
mode => 0644,
owner => 'vagrant',
group => 'vagrant',
}
}

Answer 3

You can try something like this:
file { 'bash_profile.local':
ensure => present,
source => ['puppet:///modules/local/bash_profile.local', '/dev/null'],
path => '/home/vagrant/.bash_profile.local',
before => Exec['clean-useless-file'],
}
exec { 'clean-useless-file':
command => 'rm .bash_profile.local',
onlyif => 'test -s .bash_profile.local',
cwd => '/home/vagrant',
path => '/bin:/usr/bin',
}
If the admin don't make a copy of ".bash_profile.local" available in "modules/local/bash_profile.local", the file resource will use the second source and then create a blank file. Then, the "onlyif" test fails and the exec will remove the useless blank file.
Used this way this code can be a little cumbersome, but it's better than a provisioning failure. You may evaluate if retaining a blank .bash_profile.local file can be okay in your case. I normally use a variation of this, with wget instead of rm, to get a fresh copy of the file from the internet if it was not already made available as a source.
If you're using puppetmaster, be aware you can use it to provision the own server, presenting two versions of the catalog, according to the .bash_profile.local is present or not.