I've developed the following pattern. Please don't hate.
[nibz@pdxudev01 sandbox]$ cat testpuppetfailtemplate.sh
$bar = 'lies'
$derp=inline_template("<%= @bar || scope.function_fail(['die']) %>")
notify { $derp: }
Which produces:
[nibz@pdxudev01 sandbox]$ puppet apply testpuppetfailtemplate.sh
Notice: lies
Notice: /Stage[main]//Notify[lies]/message: defined 'message' as 'lies'
Notice: Finished catalog run in 0.09 seconds
Then commenting out $bar
[nibz@pdxudev01 sandbox]$ puppet apply testpuppetfailtemplate.sh
Error: Failed to parse inline template: die at
/home/nibz/sandbox/testpuppetfailtemplate.sh:4 on node
pdxudev01.devtst.go2uti.com
Error: Failed to parse inline template: die at
/home/nibz/sandbox/testpuppetfailtemplate.sh:4 on node
pdxudev01.devtst.go2uti.com
:)
On Wednesday, July 17, 2013 8:29:07 AM UTC-7, jcbollinger wrote:
>
>
>
> On Monday, July 15, 2013 11:25:50 AM UTC-5, Brano Zarnovican wrote:
>>
>> Hi,
>>
>> I have the following code snippet
>>
>> node default {
>> # $var_a .. is undefined
>> $var_b = hiera("var_b", undef)
>> $var_c = undef
>>
>> file { "/var/tmp/foo.txt": content => inline_template("
>>
>> <% if @var_a %>
>> var_b = <%= @var_a %>
>> <% else %>
>> <% info(\"var_a is undefined\") %>
>> <% end -%>
>>
>> <% if @var_b %>
>> var_b = <%= @var_b %>
>> <% else %>
>> <% info(\"var_b is undefined\") %>
>> <% end -%>
>>
>> <% if @var_c %>
>> var_c = <%= @var_c %>
>> <% else %>
>> <% info(\"var_c is undefined\") %>
>> <% end -%>
>>
>> "
>> ), }
>> }
>>
>> Applying it, will generate these two info messages.
>>
>> Info: template[inline]: var_a is undefined
>> Info: template[inline]: var_c is undefined
>> var_b =
>>
>> What I would like puppet to do is to fail if template is referencing a
>> variable which is not defined, without having to wrap it with
>> if-else-fail()-end.
>>
>> Another strange thing I've noticed that "undef" behaves differently if it
>> is a default value for hiera lookup (see var_b vs var_c).
>>
>> Actually, my code looks more like..
>>
>> $var_a = hiera("var_a")
>> $var_b = hiera("var_b")
>> $var_c = hiera("var_c")
>> file {"..": content => template(hiera("tmpl_name")) }
>>
>> That will fail if any variable a,b,c is undefined in hiera, no matter if
>> it is used in template or not. I can rewrite it to
>>
>> $var_a = hiera("var_a", undef)
>> $var_b = hiera("var_b", undef)
>> $var_c = hiera("var_c", undef)
>> file {"..": content => template(hiera("tmpl_name")) }
>>
>> This will not fail even if variable used by the template is undefined.
>> The value is quietly replaced by empty string.
>>
>> In other words, I would like to delay the failure from hiera() lookup to
>> the time when it is actually used in template. Can it be done without
>> explicitly testing it with "if" inside template ?
>>
>> Thanks,
>>
>> BranoZ
>>
>> PS: we are (or soon be) on puppet 3.2.
>>
>>
>
> You have a couple of separate issues here, but first a little background
> to make sure we're on the same page: templates are evaluated by the master,
> not by agents, so the only form of failure a template can exhibit is to
> interrupt catalog compilation with a synthetic parse error. It cannot
> cause application of the associated resource to fail on the agent.
>
> With that said, a template can call Puppet function via the 'scope' object
> available to it. In particular, if you want a template evaluation to fail
> as I describe, then it can invoke the fail() function:
>
> <% scope.function_fail('variable foo is not set') %>
>
>
> Now, as a separate matter, you are correct that hiera will translate the
> default value 'undef' to an empty string. It will never return an undef
> value (I'm not sure that even makes sense). A common approach is to
> instead choose a default value that you are confident will not appear as a
> valid value in your data. One conventional choice is 'NOTSET'. Your code
> then tests for that special value instead of (or in addition to) testing
> whether the variable is defined.
>
>
> John
>
>
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