Class: Karafka::Instrumentation::Callbacks::Statistics

Inherits:
Object
  • Object
show all
Defined in:
lib/karafka/instrumentation/callbacks/statistics.rb

Overview

Statistics callback handler

See Also:

  • for details on why we decorate those statistics

Instance Method Summary collapse

Constructor Details

#initialize(subscription_group_id, consumer_group_id, client_name, monitor) ⇒ Statistics

Returns a new instance of Statistics.

Parameters:

  • subscription_group_id (String) —

    id of the current subscription group

  • consumer_group_id (String) —

    id of the current consumer group

  • client_name (String) —

    rdkafka client name

  • monitor (WaterDrop::Instrumentation::Monitor) —

    monitor we are using



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# File 'lib/karafka/instrumentation/callbacks/statistics.rb', line 14

def initialize(subscription_group_id, consumer_group_id, client_name, monitor)
  @subscription_group_id = subscription_group_id
  @consumer_group_id = consumer_group_id
  @client_name = client_name
  @monitor = monitor
  @statistics_decorator = ::Karafka::Core::Monitoring::StatisticsDecorator.new
end

Instance Method Details

#call(statistics) ⇒ Object

Emits decorated statistics to the monitor

Parameters:

  • statistics (Hash) —

    rdkafka statistics



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# File 'lib/karafka/instrumentation/callbacks/statistics.rb', line 24

def call(statistics)
  # Emit only statistics related to our client
  # rdkafka does not have per-instance statistics hook, thus we need to make sure that we
  # emit only stats that are related to current producer. Otherwise we would emit all of
  # all the time.
  return unless @client_name == statistics['name']

  @monitor.instrument(
    'statistics.emitted',
    subscription_group_id: @subscription_group_id,
    consumer_group_id: @consumer_group_id,
    statistics: @statistics_decorator.call(statistics)
  )
end