Class: CapsuleCD::TransformEngine

Inherits:
Object
  • Object
show all
Defined in:
lib/capsulecd/base/transform_engine.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ TransformEngine

Returns a new instance of TransformEngine.



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# File 'lib/capsulecd/base/transform_engine.rb', line 7

def initialize()
end

Instance Method Details

#populate_engine_extension ⇒ Object 



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# File 'lib/capsulecd/base/transform_engine.rb', line 25

def populate_engine_extension()
  # lets loop though all the keys, and raise an error if the hooks specified are not available.
  if @type == :repo
    @config.keys.each do |key|
       fail CapsuleCD::Error::EngineTransformUnavailableStep, key + ' cannot be overridden by repo capsule.yml file.' if %w(source_configure source_process_pull_request_payload source_process_push_payload runner_retrieve_payload).include?(key)
    end
  end

  # yeah yeah, metaprogramming is evil. But actually its really just a powerful tool, albeit a really complicated one.
  # Like any tool, you can use it incorrectly. With great power comes.. yada yada.
  # In general metaprogramming is bad because it makes it hard to reason about your code. In this case we're using it
  # to allow other developers to override our engine steps, and/or attach to our hooks. In this case its their
  # responsibility not to f*&^ it all up.

  # http://www.monkeyandcrow.com/blog/building_classes_dynamically/
  # https://rubymonk.com/learning/books/5-metaprogramming-ruby-ascent/chapters/24-eval/lessons/68-class-eval
  # https://www.ruby-forum.com/topic/207350
  @config.each do |step, value|
    next unless %w(source_configure source_process_pull_request_payload source_process_push_payload runner_retrieve_payload build_step test_step package_step source_release release_step).include?(step)

    value.each do |prefix, method_script|
      EngineExtension.class_eval(<<-METHOD
      def #{prefix == 'override' ? '' : prefix+ '_'}#{step};
        #{method_script};
      end
METHOD
)
    end
  end
end

#register_extension ⇒ Object

at this point the EngineExtension module should be populated with all the hooks and methods. now we need to add them to the engine.



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# File 'lib/capsulecd/base/transform_engine.rb', line 58

def register_extension
  @engine.class.prepend(CapsuleCD::EngineExtension)
end

#transform(engine, config_file, type = :repo) ⇒ Object

type can only be :repo or :global



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# File 'lib/capsulecd/base/transform_engine.rb', line 10

def transform(engine, config_file, type = :repo) #type can only be :repo or :global
  @engine = engine
  @type = type

  if !config_file || !File.exists?(config_file)
    puts "no #{type} configuration file found, no engine hooks applied"
    return
  end

  #parse the config file and generate a module file that we can use as part of our engine
  @config = YAML.load(File.open(config_file).read)
  populate_engine_extension
  register_extension
end