[chef] Using "subscribes" in recipes

[< >]

Hi, I'm trying to make a modification to a package that is installed by 
several
different recipes.

Since I'm trying not to modify the the cookbook directly, I believe the best
way to do this is to create a recipe with some actions that include a
"subscribes" line. After reading the documentation, some googling, and a 
number
of attempts, I'm still a bit unclear on how to do this.

Any tips on how to do this correctly would be appreciated. Here's what I've
tried so far:

--------------
# In main cookbook
package "tomcat" do
  action :install
end

--------------
# In my (simplified) recipe

directory "/bigdrive/tomcat/tmp" do
  owner node['tomcat']['user']
  group node['tomcat']['group']
  mode 0755
  action :create
  subscribes :install, resources("packages[tomcat]"), :immediately
end

# Update configuration
ruby_block "update_tomcat_defaults" do
  block do
    file =
Chef::Util::FileEdit.new("/etc/default/tomcat#{node["tomcat"]["base_version"]}")
    props = [ "export JVM_TMP=\"/bigdrive/tomcat/tmp\"" ]
    file.insert_line_after_match(/LANG\=/, props.join("\n"))
    file.write_file
  end
  subscribes :install, resources("packages[tomcat]"), :immediately
end