[chef] Re: Re: Re: Re: How to override node attribute with lazy value?

[Lamont Granquist < >]

Just move that into a computation in recipe code that is stored in a 
variable and not in a node attribute:

in default.rb:

ssl_certificate = node["chef-server"]["configuration"]["nginx"][ 
"ssl_certificate"] ||=
  "/etc/pki/tls/certs/%{node["fqdn"]}.pem"

then don't set that attribute in the attribute file, leave it only as a 
hook for someone to override the computation with.

See https://github.com/lamont-granquist/erlang_one for an example 
cookbook I wrote last night, with tests showing that you can wrap the 
cookbook the way that people want to.  Works without computed attributes 
directly in the attributes file, it exposes the kind of behavior so that 
what the recipe does is computed from the input attributes.  Since it 
uses a ruby variable instead of setting node attributes in recipe code 
there's no attribute precedence issues.

On Fri Oct 3 07:21:32 2014, Christine Draper wrote:
> Greg,
>
> Using Noah's approach, you'd have something like this in your
> attribute file, to establish the pattern for the derived attribute:
>
> node["chef-server"]["configuration"]["nginx"][ "ssl_certificate"] =
> "/etc/pki/tls/certs/%{fqdn}.pem" }
>
> And then this in your recipe where actually wanted to realize the value:
>
> node["chef-server"]["configuration"]["nginx"][ "ssl_certificate"] % {
> fqdn : node[:fqdn] }
>
> Hope this helps.
> Christine
>
>
>
> "/etc/pki/tls/certs/#{node[:fqdn]}.pem" }
>
>
> On Thu, Oct 2, 2014 at 11:18 AM, Greg Barker 
> <
>  
> <mailto:
>  >>
>  wrote:
>
> Thanks Noah. I tried it out but I don't think I'm doing it right.
>
> node["chef-server"]["configuration"]["nginx"] % { ssl_certificate:
> "/etc/pki/tls/certs/#{node[:fqdn]}.pem" }
>
> This resulted in:
>
> NoMethodError - undefined method `%' for nil:NilClass
>
> So before that line I added:
>
> node.default["chef-server"]["configuration"]["nginx"] = {}
>
> But now I get the error:
>
> NoMethodError - Undefined node attribute or method `%' on `node'
>
> Any ideas?
>
> On Thu, Oct 2, 2014 at 7:55 AM, Noah Kantrowitz
> <
>  
>  
> <mailto:
>  >>
>  wrote:
>
>
> On Oct 2, 2014, at 3:13 AM, Greg Barker 
> <
>  
> <mailto:
>  >>
>  wrote:
>
> > The chef-server readme shows how to override nginx
> attributes. However, it doesn't seem to work like I want it to
> when I do:
> >
> >
> node.override["chef-server"]["configuration"]["nginx"]["ssl_certificate"]
> = "/etc/pki/tls/certs/#{node[:fqdn]}.pem"
> >
> > node[:fqdn] is being updated during my chef run using the
> hostname cookbook, and so using the above results in an error
> because chef-server ends up looking for
> /etc/pki/tls/certs/localhost.pem (the old hostname), when it
> should instead be using
> /etc/pki/tls/certs/mynode.mycompany.com.pem.
> >
> > So I think I want something like the following, but this
> doesn't work. What's the right way to do it?
> >
> >
> node.override["chef-server"]["configuration"]["nginx"]["ssl_certificate"]
> = lazy { "/etc/pki/tls/certs/#{node[:fqdn]}.pem" }
>
> lazy{} is a feature of resources, not of node attributes. See
> https://coderanger.net/derived-attributes/ for more
> information about how to handle delayed interpolation in node
> attributes.
>
> --Noah