Converting a Kitchen YAML to Chef Attributes

This is an article that's been on the backlog for four and a half years, so I thought I should get around to actually writing it. Apologies if the context isn't quite right, as I'm trying to remember what I can for why we needed this.

You're hopefully testing your Chef cookbooks with Test Kitchen as part of a set of sufficient test coverage.

You may be finding that you've got your Test Kitchen's suites set up with a nice set of attributes that you want to move into your cookbook's attributes/ directory, but need some way to programmatically convert it, instead of doing it by hand.

(I won't recommend this (see also Chef Attributes and default.rb - it's in the name), but this is what we were doing, and we needed a straightforward way to convert the two)

Let's take the following kitchen.yml:

# ...
suites:
  - name: default
    run_list:
      - recipe[cookbook-spectat::default]
    attributes:
      spectat:
        authorized_keys: ['fake-ssh-public-key']
  # ...
  # more suites
  # ...
  - name: web-review-apps
    run_list:
      - recipe[cookbook-spectat::site]
    provisioner:
      client_rb:
        environment: staging
    attributes:
      spectat:
        site_fqdn: 'longfqdnwww.spectatdesigns.co.uk'
        admin_user: 'root'
        web_user: 'root'
        review_apps: true
        site_type: 'static'
        dns:
          api_key: 'fakeAPIkey'
        tls:
          strategy: 'self_signed'
  - name: web-docker
    run_list:
      - recipe[cookbook-spectat::site]
    attributes:
      spectat:
        site_fqdn: 'longfqdnwww.spectatdesigns.co.uk'
        admin_user: 'root'
        web_user: 'root'
        docker: true
        site_type: 'static'
        dns:
          api_key: 'fakeAPIkey'
        tls:
          strategy: 'self_signed'
        not_set: null

Then with the following script:

require 'yaml'

def keys_to_attributes(keys)
  acc = %w[default]
  acc << keys.map { |k| "['#{k}']" }
  acc.join ''
end

def output_hash(previous_keys, hash)
  hash.each do |k, v|
    keys = previous_keys.dup << k
    if v.is_a? Hash
      output_hash(keys, v)
    else
      puts "#{keys_to_attributes(keys)} = #{v.inspect}"
    end
  end
end

doc = YAML.load_file ARGV[0]
suite_name = ARGV[1] || 'default'

suite = doc['suites'].find { |s| s['name'] == suite_name }

raise "Suite `#{suite_name}` not found" if suite.nil?

output_hash([], suite['attributes'])

Which we can then execute like so:

# to use the `default` suite
$ ruby ktoa.rb kitchen.yml
# to use a specific suite
$ ruby ktoa.rb kitchen.yml web-docker

Which outputs the following when executing against web-docker:

default['spectat']['site_fqdn'] = "longfqdnwww.spectatdesigns.co.uk"
default['spectat']['admin_user'] = "root"
default['spectat']['web_user'] = "root"
default['spectat']['docker'] = true
default['spectat']['site_type'] = "static"
default['spectat']['dns']['api_key'] = "fakeAPIkey"
default['spectat']['tls']['strategy'] = "self_signed"
default['spectat']['not_set'] = nil

Written by Jamie Tanna's profile image Jamie Tanna on , and last updated on .

Content for this article is shared under the terms of the Creative Commons Attribution Non Commercial Share Alike 4.0 International, and code is shared under the Apache License 2.0.

#blogumentation #chef #test-kitchen.

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