Class: Hermes::ConsumerBuilder

Inherits:
Object
  • Object
show all
Defined in:
lib/hermes/consumer_builder.rb

Instance Method Summary collapse

Instance Method Details

#build(event_class, consumer_config: -> {}) ⇒ Object 



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# File 'lib/hermes/consumer_builder.rb', line 5

def build(event_class, consumer_config: -> {})
  queue = queue_name_from_event(event_class)
  routing_key = event_class.routing_key
  consumer_name = consumer_name_from_event(event_class)

  consumer = Class.new do
    include ::Hutch::Consumer

    consume routing_key
    queue_name queue
    instance_exec(&consumer_config)

    define_method :process do |message|
      instrumenter.instrument("Hermes.Consumer.process") do
        body = message.body
        headers = message.properties[:headers].to_h

        registration = config.event_handler.registration_for(event_class)

        if registration.async?
          config.background_processor.public_send(
            config.enqueue_method, event_class.to_s, body.as_json, headers.as_json
          )
          logger.log_enqueued(event_class, body, headers, config.clock.now)
        else
          ensure_database_connection!
          begin
            result = event_processor.call(event_class.to_s, body, headers)
          rescue StandardError => error
            rescue_from_closed_db_connection(error)
            raise error
          end
          event = result.event
          response = result.response

          if registration.rpc?
            message.delivery_info.channel.default_exchange.publish(
              response.to_json,
              routing_key: message.properties.reply_to,
              correlation_id: message.properties.correlation_id,
              headers: event.to_headers
            )
          end
        end
      end
    end

    private

    def instrumenter
      Hermes::DependenciesContainer["instrumenter"]
    end

    def logger
      Hermes::DependenciesContainer["logger"]
    end

    def config
      Hermes::DependenciesContainer["config"]
    end

    def event_processor
      Hermes::DependenciesContainer["event_processor"]
    end

    def ensure_database_connection!
      config.database_connection_provider.connection.reconnect! if config.database_connection_provider
      Hermes::DistributedTrace.connection.reconnect! if config.store_distributed_traces?
    end

    def rescue_from_closed_db_connection(error)
      if error.to_s.include?("PG::ConnectionBad")
        config.database_connection_provider.connection_pool.disconnect! if config.database_connection_provider
        Hermes::DistributedTrace.connection_pool.disconnect! if config.store_distributed_traces?
      end
    end
  end

  register_consumer(consumer_name, consumer)
  Object.const_get(consumer_name)
end