Puppet3 | read values from different yaml file

Question

So I'm using puppet3 and I have X.yaml and Y.yaml. X.yaml has profiles::resolv_conf::nameservers: [ '1.1.1.1', '8.8.8.8', '2.2.2.2' ]in it. I want to add that [ '1.1.1.1', '8.8.8.8', '2.2.2.2' ] as a value to the servers: which is in Y.yaml:

 'dns_test':
plugin_type: 'dns_query'
options:
'servers': \['1.1.1.1', '8.8.8.8', "2.2.2.2"\]
'domains': \['google.com'\]
'record_type': 'A'
'timeout': 5
tags:
'input_source': 'dns_query'

By doing this I want to make sure that when someone change values in profiles::resolv_conf::nameservers: that value is changed in this telegraf plugin too.

I tried multiple solution but the one that was the closest was:

 'dns_test': 
plugin_type: 'dns_query'     
options:       
'servers': "%{hiera('profiles::resolv_conf::nameservers')}"       
'domains': ['google.com']       
'record_type': 'A'       
'timeout': 5     
 tags:       'input_source': 'dns_query'

but problem is that puppet was adding extra " " to the value and final value in plugin conf was: "["1.1.1.1", "2.2.2.2", "8.8.8.8"]" instead of ["1.1.1.1", "2.2.2.2", "8.8.8.8"]

@JohnBollinger I agree but it's still used somewhere and I'm trying to find the way to implement idea from above. The biggest problem is that puppet doesn't have documentation for puppet3 and most of puppet users are using puppet 5+ so it's pretty hard to find good answer. — Codemypath, Apr 05 '22 at 09:16

score 0 · Accepted Answer · answered Apr 06 '22 at 00:46

TL;DR: You can't.

From the current docs and the Puppet documentation archive, I confirm that no version of the %{hiera} interpolation function or its replacement, %{lookup}, ever supported interpolating values other than strings. That's expressed in the current docs like so:

The lookup and hiera interpolation functions look up a key and return the resulting value. The result of the lookup must be a string; any other result causes an error.

(Emphasis added)

What you're looking for would be supported by Hiera 5's %{alias} function, provided that the data are available somewhere else in the same hierarchy (which is also a requirement for %{hiera}). Since you're stuck on Puppet 3, however, you're probably on Hiera 2, and certainly not later than Hiera 3.

"But wait!" You may say. "I'm getting a successful interpolation, but the data are just munged". Specifically, you wrote:

problem is that puppet was adding extra " " to the value and final value

Since %{hiera()} interpolates only strings, it is not surprising that you got a string value, given that you got a value at all. I do find it a bit surprising that Puppet did not throw an error, but I'm not prepared to comment further on that without a minimum reproducible example that demonstrates the behavior.

Puppet3 | read values from different yaml file

1 Answers1