[chef] Re: Re: Re: where is the better place for this code?

[Andrea Campi < >]

2011/11/16 Juan Jesús Ojeda Croissier 
<
 >:
> On Wed, Nov 16, 2011 at 9:19 AM, Andrea Campi
>> On Nov 16, 2011, at 12:41 AM, Juan Jesús Ojeda Croissier 
>> <
 >
>>  wrote:
> [...]
>>> I wrote some code for this (which is currently working), but I don't
>>> know if I did in the right place and in the right way. I love to have
>>> it at Chef, but I guess it need to be proven useful and the community
>>> agree. By now I put it in my cookbooks at:
>>> cookbooks/the_cookbook/libraries/file.rb
>>>
>>> Here is the actual code and example or recipe using it:
>>> https://gist.github.com/1368640
>>>
>>> But I'll write down here a simplier version:
>>>
>>> def include?(str)
>>>  file_content = ::File.open(@path).read
>>>  return true if file_content =~ /#{str}/
>>>  return false
>>> end
>>>
>>> def replace(str, str2)
>>>  old_content = ::File.open(@path).read
>>>  content old_content.gsub(str, str2)
>>> end
>>>
>>> These methods are Chef::Resource::File's methods. I wrote like that
>>> because was the only way I got them working, but it seems to me that
>>> it should be a Providers' instead... I don't know...
>>
>> Looking only at your gist it's a wash, but in general yes, I would use an 
>> LWRP. Keep the library, but put the "file" resource in an LWRP.
>>
>
> Sorry, but I don't get what you are saying :-/ I thing my English is
> not as good as I thought. What do you mean by 'wash'?

Ah, sorry, it's kind of idiomatic—I meant "you can do it either way,
each has pros and cons".

> Could you explain to me what do you mean by keep the library but
> putting the 'file' resource in an LWRP? I'm a bit confuse, sorry.

Sure.
In your gist, I wouldn't change anything in the library; I would
remove the recipe and replace it with an LWRP:

resources/gtk_bookmarks.rb

action :replace # and possibly more

attribute :name, :kind_of => String, :name_attribute => true
attribute :owner, :kind_of => String
attribute :group, :kind_of => String
attribute :before, :kind_of => String
attribute :after, :kind_of => String


providers/gtk_bookmarks.rb

action :replace do
  file new_resource.name do
    replace(new_resource.before, new_resource.after) if
include?(new_resource.before)
    owner new_resource.owner
    group new_resource.group
    mode "0644"
    action :create_if_missing
  end
end


This way you can call it with:

<cookbook_name>_gtk_bookmarks "/home/#{node.user}/.gtk-bookmarks" do
  before "smb"
  after "smb"
  owner node.user
  group node.user
  action :replace
end


Makes more sense?


Just for completeness: in this case it would probably be easier/faster
to use a definition instead. But the LWRP is useful in case you want
to add other actions (:add, :replace, :gsub come to mind).

definitions/gtk_bookmarks.rb

define :gtk_bookmarks_replace do
  file params[:name] do
    replace(params[:before], params[:after]) if include?(params[:before])
    owner params[:owner]
    group params[:group]
    mode "0644"
    action :create_if_missing
  end
end

You would call this in the exact same way.


One more thing to keep in mind in all cases, even your first:
resources are unique per run, so if you try to modify this same file
twice in a run, that's going to be a problem. That's true in general,
but when you introduce LWRPs and definitions it may become hard to
diagnose.
The solution here would be something like:

filename = "/path/to/your/file"
file "#{filename} (replace)" do
  path filename
  # and then everything else
end

Basically this will just make give the resource a unique name (which
will show up in logs), and then set the "real" path.

Hope it helps.

Andrea