Module: RailsPipeline::Subscriber::InstanceMethods

Defined in:
lib/rails-pipeline/subscriber.rb

Instance Method Summary collapse

Instance Method Details

#_api_keys ⇒ Object 



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# File 'lib/rails-pipeline/subscriber.rb', line 168

def _api_keys
  return ENV.fetch('PIPELINE_API_KEYS', "").split(',')
end

#_version(payload) ⇒ Object 



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# File 'lib/rails-pipeline/subscriber.rb', line 163

def _version(payload)
  _, version = payload.class.name.split('_', 2)
  return RailsPipeline::PipelineVersion.new(version)
end

#handle_envelope(envelope) ⇒ Object

Take an EncryptedMessage envelope, and decrypt the cipher text, then get the protobuf object out of it



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# File 'lib/rails-pipeline/subscriber.rb', line 51

def handle_envelope(envelope)
  if ENV.has_key?("DISABLE_RAILS_PIPELINE") || ENV.has_key?("DISABLE_RAILS_PIPELINE_PROCESSING")
    RailsPipeline.logger.debug "Skipping incoming pipeline messages (disabled by env vars)"
    return
  end
  verify_api_key(envelope)
  payload_str = self.class.decrypt(envelope)

  # Find the registered minor version & its related handler to parse and
  # process this message.
  clazz = registered_class_on_same_major_version(envelope.type_info)

  if clazz.nil?
    # No compatible version of this message is registered for this app.
    RailsPipeline.logger.info "Dropping unclaimed message #{envelope.type_info} (no compatible version registered)."
    return
  end

  # Parse and handle the payload.
  payload = clazz.parse(payload_str)
  handle_payload(payload, envelope)
end

#handle_payload(payload, envelope) ⇒ Object

Take a protobuf object (payload) and forward it to the appropriate handler/method/proc



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# File 'lib/rails-pipeline/subscriber.rb', line 76

def handle_payload(payload, envelope)
  version = _version(payload)
  clazz = target_class(payload)
  handler_class = target_handler(payload)
  event_type = envelope.event_type
  method = most_suitable_handler_method_name(version, clazz)

  if clazz.is_a?(Class)
    if handler_class
      # If a built in handler_class is registered, then just use it
      handler_class.new(payload, target_class: clazz, envelope: envelope).handle_payload
    elsif method
      # Target class had a from_pipeline method, so just call it and move on
      target = clazz.send(method, payload, event_type)
    else
      RailsPipeline.logger.info "No handler set, dropping message #{payload.class.name}"
    end
    return target
  elsif clazz.is_a?(Proc)
    return clazz.call(payload)
  end
end

#most_suitable_handler_method_name(version, receiver_class) ⇒ Object 



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# File 'lib/rails-pipeline/subscriber.rb', line 127

def most_suitable_handler_method_name(version, receiver_class)
  # Returns the closest lower implemented method in target_class for the given version
  cached_method = self.class.handler_method_cache[version]
  if cached_method
    return cached_method
  end
  available_methods = receiver_class.methods.grep(%r{^from_pipeline_#{version.major}})
    .reject { |method_name| method_name.to_s.split('_').last.to_i > version.minor }
    .sort
    .reverse

  # cache handler method for this version
  self.class.handler_method_cache[version] = available_methods.first
  return available_methods.first
end

#registered_class_on_same_major_version(payload_class_name) ⇒ Object 



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# File 'lib/rails-pipeline/subscriber.rb', line 99

def registered_class_on_same_major_version(payload_class_name)
  if Subscriber.registered_handlers.has_key?(payload_class_name)
    # The version we've been given has been registered. Return that.
    return Object.const_get(payload_class_name)
  end

  # Lops off the minor version from the payload class name so
  # we can find the registered message type with the same major version.
  class_name_with_major_version =
    payload_class_name
    .split("_", 3)[0, 2]
    .join("_")

  # Look for message types with the same major version.
  available_classes = Subscriber.registered_handlers
    .keys
    .map(&:to_s)
    .select { |class_name| class_name.start_with?(class_name_with_major_version) }

  if available_classes.empty?
    # No message types with the same major version.
    return nil
  else
    # There's a message type with the same major version.
    return Object.const_get(available_classes.first)
  end
end

#target_class(payload) ⇒ Object 



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# File 'lib/rails-pipeline/subscriber.rb', line 155

def target_class(payload)
  RailsPipeline::Subscriber.target_class(payload.class)
end

#target_handler(payload) ⇒ Object 



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# File 'lib/rails-pipeline/subscriber.rb', line 159

def target_handler(payload)
  RailsPipeline::Subscriber.target_handler(payload.class)
end

#verify_api_key(envelope) ⇒ Object 



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# File 'lib/rails-pipeline/subscriber.rb', line 143

def verify_api_key(envelope)
  if envelope.api_key.present?
    if _api_keys.include?(envelope.api_key)
      return true
    else
      raise WrongApiKeyError.new
    end
  else
    raise NoApiKeyError.new
  end
end