[chef] Re: Re: howto install a ruby gem that's a pre-req of a chef recipe

[Bryan McLellan < >]

On Thu, Aug 16, 2012 at 1:12 PM, Joshua Blatt 
<
 >
 wrote:
> After playing with this a bit, I found that chef loads libraries before the 
> recipe is compiled so sometimes you can't use that gem_package resource in 
> time.

libraries are evaluated before recipes in the compilation phase [1].
What you need to do is a) use chef_gem and b) move your requires in
your libraries where they aren't evaluated until the recipe is
converged.

# library_gem/libraries/check_mysql.rb
module CheckMysql
  def check
    require 'mysql'

    # do something
  end
end
# EOF

# library_gem/recipes/default.rb
class Chef::Recipe
  include CheckMysql
end

chef_gem "mysql"

check
# EOF

> I also noticed that the opscode database cookbook has this problem too.     
> The 'added:' lines below addressed the problem for me, but is this a 
> colossal hack?   Would love to know if I'm doing something stupid here or 
> depending on internals that may change in the future….

That is an unnecessary hack.

The mysql gem should (must) be installed with chef_gem (or the old
gem_package.run_action hack) in a recipe before the mysql library is
required in a chef cookbook library.

The simplest course of action for this part of the discussion is to
look at the database cookbook refactor that was recently completed
[1].

Bryan

[1] http://lists.opscode.com/sympa/arc/chef/2012-08/msg00206.html