chef

https://github.com/opscode/chef

Ruby

A systems integration framework, built to bring the benefits of configuration management to your entire infrastructure.

Chef::Resource#subscribes

Subscribes to updates from other resources, causing a particular action to
run on *this* resource when the other resource is updated.

If multiple resources are specified, this resource action will be run if
*any* of them change.

This notification will only trigger *once*, no matter how many other
resources are updated (or how many actions are run by a particular resource).

Source | Google | Stack overflow

Edit

git clone [email protected]:opscode/chef.git
cd chef
open lib/chef/resource.rb

Contribute

# Make a new branch

git checkout -b -your-name--update-docs-Chef--Resource-subscribes-for-pr

# Commit to git

git add lib/chef/resource.rbgit commit -m "better docs for Chef::Resource#subscribes"

# Open pull request

gem install hub # on a mac you can `brew install hub`

hub fork

git push <your name> -your-name--update-docs-Chef--Resource-subscribes-for-pr

hub pull-request

# Celebrate!