Puppet, hiera and erb - erb would not recognize array

Question

I have a pretty annoying error I am desperate to fix. I have a puppet module where certain things are kept in a yaml file (hiera) so that people could quickly edit just that part.

The structure is nested.

The template like this:

<%= @platforms[@platform]['users_allowed'][@host].class %>

renders to this:

Array

But when I try to iterate over it:

<% @platforms[@platform]['users_allowed'][@host].each do | pubkey | %>
<%= pubkey %>
<% end %>

puppet says:

Error: Could not retrieve catalog from remote server: Error 400 on SERVER: Failed to parse template somemodule/templates/authorized_keys.erb:
Filepath: /etc/puppet/modules/somemodule/templates/authorized_keys.erb
Line: 1
Detail: undefined method `each' for nil:NilClass

How does it suddenly become nil and how do I iterate here?

I'm afraid I'm stuck here and not even sure in which direction I should search for solution.

Rewriting module without hiera or without nested structure is not an option in this one case.

Solution

I've tested on my puppet and the correct syntax that worked was:

<% @platforms[@platform]['users_allowed'][@host].each do | pubkey | -%>
  <%= pubkey %>
<% end -%>

I hope I helped.

Comments

[Zypher]

what version of puppet?

[Roman Grazhdan]

It's 3.3.1. I belive the part of the problem is this (quoting puppetlabs docs): The lookup functions and the automatic parameter lookup always return the values of top-level keys in your Hiera data — they cannot descend into deeply nested data structures and return only a portion of them. To do this, you need to first store the whole structure as a variable, then index into the structure from your Puppet code or template. -- but it's still weird to me. It does see the type and it can render a template with the whole array but it can't index.

[Roman Grazhdan]

What version of puppet do you run? I think omitting one pipe must not help and if it does I'm in trouble. I mean, in Ruby array.each do | i | is valid, so it should be valid in erb, too.

[PoLIVoX]

When I typed I forgot to type a |. I already fix. Sorry for the mistake. Answering your question: Puppet 3.4.3. I used as the documentation recommends: docs.puppetlabs.com/learning/templates.html