[Puppet Users] Can ERB templates be used to process hashes of arbitrary depth?

[Andreas Ntaflos]

Hi list,

I am in the process of writing a module to manage strongSwan, an IKE
keying daemon for IPsec VPNs on Linux [1]. The strongSwan daemon's
(charon) configuration file is basically formatted like a hash, with
sections containing key-value pairs that may themselves contain further
sections [2]. Sections may also be empty. I don't think there is a
maximum depth defined.

It seems to me that this kind of configuration file format is easily
modelled as a Puppet/Ruby hash, so now I am wondering how I can go about
rendering the configuration file from such a hash.

Is it feasibly to use an ERB template for this? You may notice that I am
(still) not much of a Ruby guy and I don't want to reinvent any wheels,
so I am asking: what are my options?

Can ERB templates in Puppet be used to render hashes of arbitrary depth?
Or should I look to something else? Can this even be done?

I'd appreciate any and all pointers and ideas.

Here is an example hash that I would supply as a parameter to my
strongswan class:

charon_config => {
  ikesa_limit        => '0',
  install_virtual_ip => 'yes',
  keep_alive         => '20s',
  host_resolver => {
    max_threads => '3'
  },
  processor => {
    priority_threads => {
      high   => '1',
      medium => '4'
    }
  },
  tls  => {},
  x509 => {}
}

This should result in the following configuration file content (sorting
the keys is only of secondary concern):

charon {
  ikesa_limit = 0
  install_virtual_ip = yes
  keep_alive = 20s
  host_resolver {
    max_threads = 3
  }
  processor {
    priority_threads {
      high = 1
      medium = 4
    }
  }
  tls {
  }
  x509 {
  }
}

Thanks in advance,

Andreas

[1] http://www.strongswan.org/
[2] http://wiki.strongswan.org/projects/strongswan/wiki/StrongswanConf

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