Contents

# frozen_string_literal: true

module Karafka
  # Params namespace encapsulating all the logic that is directly related to params handling
  module Params
    # It provides lazy loading not only until the first usage, but also allows us to skip
    # using deserializer until we execute our logic. That way we can operate with
    # heavy-deserialization data without slowing down the whole application.
    class Params
      attr_reader :raw_payload, :metadata

      # @param raw_payload [Object] incoming payload before deserialization
      # @param metadata [Karafka::Params::Metadata] message metadata object
      def initialize(raw_payload, metadata)
        @raw_payload = raw_payload
        @metadata = metadata
        @deserialized = false
        @payload = nil
      end

      # @return [Object] lazy-deserialized data (deserialized upon first request)
      def payload
        return @payload if deserialized?

        @payload = deserialize
        # We mark deserialization as successful after deserialization, as in case of an error
        # this won't be falsely set to true
        @deserialized = true
        @payload
      end

      # @return [Boolean] did given params payload were deserialized already
      def deserialized?
        @deserialized
      end

      private

      # @return [Object] tries de-serializes data
      def deserialize
        Karafka.monitor.instrument('params.params.deserialize', caller: self) do
          metadata.deserializer.call(self)
        end
      rescue ::StandardError => e
        Karafka.monitor.instrument('params.params.deserialize.error', caller: self, error: e)
        raise e
      end
    end
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
karafka-1.4.0.rc1	lib/karafka/params/params.rb