Re: [Puppet-dev] Puppet 4: defined resource types and epp template

2016-02-04 Thread Martin Alfke 

On 01 Feb 2016, at 19:15, Henrik Lindberg  
wrote:

> 
> That is exactly what you should do. An external (file based epp) when called, 
> does not get to see variables in the scope from which it was called/used. 
> This design is deliberate. Think of the template as a function you are 
> calling, and you have to give it its arguments.

In this case the documentation on the website is wrong:
https://docs.puppetlabs.com/puppet/latest/reference/lang_template_epp.html#example-template

The example just switches from template() to epp() function.
According to your writing you must pass all parameters to the epp() function.

> 
> Contrast this with the inline_epp, which you can think of as a 
> lambda/code-block. Here the code block gets to see the variables in scope, 
> since it is itself in that scope (part of the same piece of code).
> 
Got it.
To be honest: this is ugly.
I always thought of epp() being a full replacement for template() without the 
scope issue.
This especially feels bad, when we will have performance improvement for epp in 
the future.

I need to rethink whether inline_epp() is the proper replacement for template() 
function.


> This design makes the code more maintainable and templates more reusable. It 
> is also easier to test the templates (there is a command line utility (puppet 
> epp IIRC) that allows you to feed values into a templates and render the 
> result).
> 
> Hope that helps
> - henrik
> 
>> 
>> Best,
>> Martin
>> 
> 
> 
> -- 
> 
> Visit my Blog "Puppet on the Edge"
> http://puppet-on-the-edge.blogspot.se/
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Re: [Puppet-dev] Puppet 4: defined resource types and epp template

2016-02-04 Thread Martin Alfke 

On 04 Feb 2016, at 14:30, Henrik Lindberg  
wrote:

> On 2016-04-02 11:46, Martin Alfke wrote:
>> 
>> On 01 Feb 2016, at 19:15, Henrik Lindberg  
>> wrote:
>> 
>>> 
>>> That is exactly what you should do. An external (file based epp) when 
>>> called, does not get to see variables in the scope from which it was 
>>> called/used. This design is deliberate. Think of the template as a function 
>>> you are calling, and you have to give it its arguments.
>> 
>> In this case the documentation on the website is wrong:
>> https://docs.puppetlabs.com/puppet/latest/reference/lang_template_epp.html#example-template
>> 
> The long example is wrong in that it does not show that arguments must be 
> given in a hash.
> 
> The documetation for epp has unfortunately been boiled down to just the bare 
> minimum and the important distinction that variables must be given has been 
> lost in the series of rewrites that were made.
> 
> The implementation clearly restricts epp() to only see global scope.
> 
> The specification is also clear about scoping: 
> https://github.com/puppetlabs/puppet-specifications/blob/master/language/templates.md#visibility-of-scoped-variables

Yes. the written description is clear about that.

> 
> I filed a documentation ticket.
> 
>> The example just switches from template() to epp() function.
>> According to your writing you must pass all parameters to the epp() function.
>> 
> 
> yes, epp() requires that arguments are given in the call. epp() templates 
> only have access to global variables (i.e. $::osfamily and such).
> 
> 
>>> 
>>> Contrast this with the inline_epp, which you can think of as a 
>>> lambda/code-block. Here the code block gets to see the variables in scope, 
>>> since it is itself in that scope (part of the same piece of code).
>>> 
>> Got it.
>> To be honest: this is ugly.
>> I always thought of epp() being a full replacement for template() without 
>> the scope issue.
> 
> The ERB based template() function is for templates in files. The epp() 
> function is also for files. The big difference between them is that all 
> variables used by the template processed by epp() must be given to the 
> function.
> 
> The inline_epp() may in the special case, when it does not declare parameters 
> have access to all variables in scope. This was deemed to be harmless as all 
> of the logic is in one place, and there is never a question of reuse. It is 
> also seen as an easy way to transition to inline_epp() from inline_template().
> 
> With that, I am not sure I understand your comments. What is it that you 
> think is ugly?
> 
>> This especially feels bad, when we will have performance improvement for epp 
>> in the future.
>> 
> 
> I have not seen tickets with reports of performance problems. How bad is it?

You mentioned it somewhere at PuppetConf that in the future the epp() function 
will have a performance benefit over template() function due to template() 
needing the ruby stack whereas epp() is running in the java based parser (as 
far as I have understood this).

> 
> Best
> - henrik
> 
> -- 
> 
> Visit my Blog "Puppet on the Edge"
> http://puppet-on-the-edge.blogspot.se/
> 
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[Puppet-dev] Puppet 4: defined resource types and epp template

2016-01-31 Thread Martin Alfke 
Hi,

I recently had an issue with epp template within a defined resource type.
Let’s assume the following code snippets:

# modules/test/manifests/init.pp
class test {
  ::test::files { 'test':
param1 => 'value',
  }
}

# modules/test/manifests/files.pp
define test::files (
  $param1 = '',
){
  file { "/tmp/${title}":
ensure  => file,
content => epp('test/files.epp'),
  }
}

# modules/test/templates/files.epp
<%= $param1 %>

The parameter Param1 will not get the data provided within define declaration.

Is this desired behaviour?
Should I open a bug?
Is this a known bug?

When passing the param1 data via hash to epp function, data will get added to 
the template.

Best,
Martin

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