Puppet exec command with variable not executed

Question

I have a very simple Puppet (sub)module that should use Git to clone a repository from a remote location:

class wppuppet::git(
  $location = '/var/www/wp'
) {

  file { $location:
    ensure => 'directory',
    mode   => '0755',
  }

  exec { 'git-wp':
    command => 'git clone https://github.com/WordPress/WordPress ${location}',
    require => Package['git'],
  }

  Package['git']
  -> File[ $location ]
  -> Exec['git-wp']
}

For some reason it constantly fails with the following error:

Error: git clone https://github.com/WordPress/WordPress ${location} returned 128 instead of one of [0]
Error: /Stage[main]/Wppuppet::Git/Exec[git-wp]/returns: change from notrun to 0 failed: 
git clone https://github.com/WordPress/WordPress ${location} returned 128 instead one of [0]

I tried it with ${location} as well as with $location, but the result stays the same.

Solution

Your first problem is that you have your command parameter surrounded with single quotes ('), which inhibit variable expansion. If you have:

$location = "/path/to/target"

Then:

file { '$location':
  ensure => directory,
}

Will attempt to create a directory called "$location", whereas this:

file { "$location":
  ensure => directory,
}

Would actually try to create /path/to/target.

With that in mind, your exec resource should probably look like:

exec { 'git-wp':
  command => "git clone https://github.com/WordPress/WordPress ${location}",
  require => Package['git'],
}

Also, it's not necessary to pre-create the target directory; git will do this for you.

You can run puppet with --debug in order to see the actual error messages output by git.