Identifying custom resources from resource_collection using is_a

Chef Infra (archive)
1

I’m trying to work through custom resources a bit, and I’m using a users cookbook to do it. I have one custom resource for a standard user (call it custom_user), and then I have another user that I want to have ssh keys from multiple other users in (call it special_user).

First step in that is to find all of the custom users. I have this in a helper that I’ve made available to the custom resource:

def foo
  public_keys = []
  run_context.resource_collection.each do |res|
    if res.is_a?(custom_user)
       public_keys << res.public_keys
    end
  end
end

But, that isn’t working. I replaced it with a log entry to give me inspect output, and it looks like it has a class of custom_user – but I guess I’m not sure how to refer to my custom resource in the is_a line in a way that chef/ruby will recognize.

If it was the old-school resources, I’m guessing I could fix this by making the custom_user the parent class for a special_user – but I don’t think you can do that with the new custom resources, (or at least that’s not immediately obvious to me in the docs).

2

@thewyzard on Slack pointed me at the lib/chef/resource.rb. Our initial attempts from here to find the class were unfruitful, but as I was poking around I discovered I could probably do this slightly differently:

def foo
  public_keys = []
  run_context.resource_collection.each do |res|
    if res.resource_name = :custom_user
      public_keys << res.public_keys
    end
  end
end

This works for me (or at least it passes tests). If anyone has a reason I shouldn’t do it this way, or suggestions on how to do it better I’m all ears.