Puppet iteration string/array - puppet

Question

Can you think of a way to solve this problem in Puppet?
I have a custom fact with generates a string of IP addresses depending on the domain it is run on, it can resolve to have 1 to n addresses.
"10.1.29.1"
"10.1.29.1,10.1.29.5"
"10.1.29.1,10.1.29.5,10.1.29.7"
etc
I want to add these to the host file with a generated server names of servernameX for example;
10.1.29.1 myservername1
10.1.29.5 myservername2
10.1.29.7 myservername3
So how can you do this as puppet doesn't have an array iterator like "for each"?

Answer 1

Sadly, even if you go about and use a custom "define" to iterate over an array upon splitting your custom fact on a comma, the result will be rather not what you expect and not even close to a "for each" loop -- aside of causing you a headache, probably.
Said that, I am not sure if this is what you want to achieve, but have a look at this approach:
$fact = '1.1.1.1,2.2.2.2,3.3.3.3'
$servers = split($::fact, ',')
$count = size($servers)
$names = bracket_expansion("host[01-${count}].address")
file { '/tmp/test.txt':
content => inline_template('<%= #servers.each_with_index.map {|v,i| "#{v}\t\t#{#names[i]}\n" } %>'),
ensure => present
}
What we have there are two custom functions: size() and bracket_expansion(); which we then use values that they provide inside a hack that leverages the inline_template() function to render content of the file utilising parallel access to two arrays -- one with IP addresses from your fact and one with host names that should follow.
The result is a follows:
matti#acrux ~ $ cat | puppet apply
$fact = '1.1.1.1,2.2.2.2,3.3.3.3'
$servers = split($::fact, ',')
$count = size($servers)
$names = bracket_expansion("host[01-${count}].address")
file { '/tmp/test.txt':
content => inline_template('<%= #servers.each_with_index.map {|v,i| "#{v}\t\t#{#names[i]}\n" } %>'),
ensure => present
}
notice: /Stage[main]//File[/tmp/test.txt]/ensure: created
notice: Finished catalog run in 0.07 seconds
matti#acrux ~ $ cat /tmp/test.txt
1.1.1.1 host01.address
2.2.2.2 host02.address
3.3.3.3 host03.address
matti#acrux ~ $
Both size() and bracket_expansion() functions can be found here:
https://github.com/kwilczynski/puppet-functions/tree/master/lib/puppet/parser/functions/
I hope this helps a little :-)