[chef] Re: Re: Re: Re: Re: Re: Re: node.run_state

[Lamont Granquist < >]

You should avoid setting attributes at converge-time using ruby_block 
unless you absolutely have to.  You are eventually going to have a bad 
time in later recipes when you try to use those attributes at compile 
time and they don't work the way you think they will.  You'll have to 
use lazy attributes everywhere and
that is code smell that you need to drop those ruby_blocks and move 
whatever input prep you need to do before this to compile time.

On Mon Sep 22 22:19:43 2014, DV wrote:
> Matthew,
>
> Thanks! After thinking about it and re-reading docs I think your
> suggestion got me to realize why I can't just set /node.run_state/ the
> way I can set /node.normal/:
>
> />run_state is an empty Hash that is always discarded at the end of
> the chef-client run./
>
> So I have to treat it as empty hash instead of as node's attributes
> hash, and also, it can't be used to modify cookbook behavior (because
> /node.run_state/ doesn't get merged with /node.normal/ attributes).
>
> So, for my recipe to override attributes at recipe level, I have to
> use /node.override['something'] = value/. That way I get to override
> the value, yet the override doesn't get saved to node object like it
> would with /node.normal['something'] = value/.
>
> /P.S./ The use case for this recipe is to let users override any
> cookbook attributes on per-environment, per-role basis. For example -
> enabling Tomcat debugging on particular set of webapps in particular
> environment. Normally this would require doing "knife node edit" or
> creating a special recipe to set attributes.
>
> Here's working code snippets:
>
> *Goal:* set /node['tomcat']['debug']['enabled]=true/ and
> /node['tomcat']['blah']['blah']='whatever' /on /my-webapp-1/ hosts in
> /qa-1/ environment.
>
> */my-webapp-1.rb:/*
> name "my-webapp-1"
> description "Role for my webapp 1"
> default_attributes(
>   'custom-resource' => {
>     'env_attributes' => {
>       'qa-1' => {
> *        'tomcat.debug.enabled' => true,*
> *        'tomcat.blah.blah' => 'whatever'*
>       }
>     }
>   }
> )
> run_list(...,"recipe[custom-resource]","recipe[tomcat]",...)
>
> Then the Ruby block overrides Tomcat cookbook's attributes at run time:
>
> */cookbooks/custom-resource/attributes/default.rb/*
> default["custom-resource"]["env_attributes"] = Hash.new
>
> */cookbooks/custom-resource/default.rb/*
> node["custom-resource"]["env_attributes"].each do |env, attrs|
>   if env == *node[:environment][:name]*
>     Chef::Log.info("Setting env_attributes for #{env}...")
>     attrs.each do |attr,val|
>       Chef::Log.info("Setting attribute #{attr} to #{val}")
>       if val.instance_of? String
>         ruby_block "set_attr_#{attr}" do
>           block do
> *            eval ( "node.override['" + attr.split(".").join("']['") +
> "'] = #{val}" )*
>           end
>         end
>       else
>         ruby_block "set_attr_#{attr}" do
>           block do
> *            eval ( "node.override['" + attr.split(".").join("']['") +
> "'] = #{val}" )*
>           end
>         end
>       end
>     end
>   end
> end