Class: Karafka::Web::Processing::Consumer

Inherits:
BaseConsumer
  • Object
show all
Includes:
Core::Helpers::Time
Defined in:
lib/karafka/web/processing/consumer.rb

Overview

Consumer used to squash and process statistics coming from particular processes, so this data can be read and used. We consume this info overwriting the data we previously had (if any)

Instance Method Summary collapse

Instance Method Details

#consume ⇒ Object

Aggregates consumers state into a single current state representation



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# File 'lib/karafka/web/processing/consumer.rb', line 15

def consume
  bootstrap!

  consumers_messages = messages.select { |message| message.payload[:type] == 'consumer' }

  # If there is even one incompatible message, we need to stop
  consumers_messages.each do |message|
    case @reports_schema_manager.call(message)
    when :current
      true
    when :newer
      @reports_schema_manager.invalidate!

      dispatch

      raise ::Karafka::Web::Errors::Processing::IncompatibleSchemaError
    # Older reports mean someone is in the middle of upgrade. Schema change related
    # upgrades always should happen without a rolling-upgrade, hence we can reject those
    # requests without significant or any impact on data quality but without having to
    # worry about backwards compatibility. Errors are tracked independently, so it should
    # not be a problem.
    #
    # In case user wants to do a rolling upgrade, the user docs state that this can happen
    # and it is something user should be aware
    when :older
      next
    else
      raise ::Karafka::Errors::UnsupportedCaseError
    end

    # We need to run the aggregations on each message in order to compensate for
    # potential lags.
    @state_aggregator.add(message.payload, message.offset)
    @metrics_aggregator.add_report(message.payload)
    @metrics_aggregator.add_stats(@state_aggregator.stats)
    # Indicates that we had at least one report we used to enrich data
    # If there were no state changes, there is no reason to flush data. This can occur
    # when we had some messages but we skipped them for any reason on a first run
    @established = true

    # Optimize memory usage in pro
    message.clean! if Karafka.pro?
  end

  return unless periodic_flush?

  dispatch

  mark_as_consumed(messages.last)
end

#shutdown ⇒ Object

Flush final state on shutdown



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# File 'lib/karafka/web/processing/consumer.rb', line 67

def shutdown
  dispatch
end