Class: Karafka::Instrumentation::LoggerListener

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

Overview

Default listener that hooks up to our instrumentation and uses its events for logging It can be removed/replaced or anything without any harm to the Karafka app flow.

Instance Method Summary collapse

Constructor Details

#initialize(log_polling: true) ⇒ LoggerListener

Returns a new instance of LoggerListener.

Parameters:

  • log_polling (Boolean) (defaults to: true) —

    should we log the fact that messages are being polled. This is usually noisy and not useful in production but can be useful in dev. While users can do this themselves this has been requested and asked for often, thus similar to how extensive logging can be disabled in WaterDrop, we do it here as well.

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 23

def initialize(log_polling: true)
  @log_polling = log_polling
end

Instance Method Details

#on_app_quiet(event) ⇒ Object

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 205

def on_app_quiet(event)
  info "[#{event[:server_id]}] Reached quiet mode. No messages will be processed anymore"
end

#on_app_quieting(event) ⇒ Object

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 200

def on_app_quieting(event)
  info "[#{event[:server_id]}] Switching to quiet mode. New messages will not be processed"
end

#on_app_running(event) ⇒ Object

Logs info that we’re running Karafka app.

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 188

def on_app_running(event)
  server_id = event[:server_id]

  info "[#{server_id}] Running in #{RUBY_DESCRIPTION}"
  info "[#{server_id}] Running Karafka #{Karafka::VERSION} server"

  return if Karafka.pro?

  info "[#{server_id}] See LICENSE and the LGPL-3.0 for licensing details"
end

#on_app_stopped(event) ⇒ Object

Logs info that we stopped the Karafka server.

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 219

def on_app_stopped(event)
  info "[#{event[:server_id]}] Stopped Karafka server"
end

#on_app_stopping(event) ⇒ Object

Logs info that we’re going to stop the Karafka server.

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 212

def on_app_stopping(event)
  info "[#{event[:server_id]}] Stopping Karafka server"
end

#on_client_pause(event) ⇒ Object

Note:

There may be no offset provided in case user wants to pause on the consecutive offset position. This can be beneficial when not wanting to purge the buffers.

Prints info about a consumer pause occurrence. Irrelevant if user or system initiated.

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 103

def on_client_pause(event)
  topic = event[:topic]
  partition = event[:partition]
  offset = event[:offset]
  client = event[:caller]

  info <<~MSG.tr("\n", ' ').strip!
    [#{client.id}]
    Pausing on topic #{topic}-#{partition}
    on #{offset ? "offset #{offset}" : 'the consecutive offset'}
  MSG
end

#on_client_resume(event) ⇒ Object

Prints information about resuming of processing of a given topic partition

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 119

def on_client_resume(event)
  topic = event[:topic]
  partition = event[:partition]
  client = event[:caller]

  info <<~MSG.tr("\n", ' ').strip!
    [#{client.id}] Resuming on topic #{topic}-#{partition}
  MSG
end

#on_connection_listener_before_fetch_loop(event) ⇒ Object

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 30

def on_connection_listener_before_fetch_loop(event)
  listener_id = event[:caller].id
  subscription_group = event[:subscription_group]
  consumer_group_id = subscription_group.consumer_group.id
  topics = subscription_group.topics.select(&:active?).map(&:name).join(', ')
  group_details = "#{consumer_group_id}/#{subscription_group.id}"

  info(
    "[#{listener_id}] Group #{group_details} subscribing to topics: #{topics}"
  )
end

#on_connection_listener_fetch_loop(event) ⇒ Object

Logs each messages fetching attempt

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 45

def on_connection_listener_fetch_loop(event)
  return unless log_polling?

  listener_id = event[:caller].id
  debug "[#{listener_id}] Polling messages..."
end

#on_connection_listener_fetch_loop_received(event) ⇒ Object

Logs about messages that we’ve received from Kafka

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 55

def on_connection_listener_fetch_loop_received(event)
  return unless log_polling?

  listener_id = event[:caller].id
  time = event[:time].round(2)
  messages_count = event[:messages_buffer].size

  message = "[#{listener_id}] Polled #{messages_count} messages in #{time}ms"

  # We don't want the "polled 0" in dev as it would spam the log
  # Instead we publish only info when there was anything we could poll and fail over to the
  # zero notifications when in debug mode
  messages_count.zero? ? debug(message) : info(message)
end

#on_consumer_consuming_retry(event) ⇒ Object

Prints info about retry of processing after an error

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 132

def on_consumer_consuming_retry(event)
  topic = event[:topic]
  partition = event[:partition]
  offset = event[:offset]
  consumer = event[:caller]
  timeout = event[:timeout]

  info <<~MSG.tr("\n", ' ').strip!
    [#{consumer.id}] Retrying of #{consumer.class} after #{timeout} ms
    on topic #{topic}-#{partition} from offset #{offset}
  MSG
end

#on_consumer_consuming_seek(event) ⇒ Object

Prints info about seeking to a particular location

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 148

def on_consumer_consuming_seek(event)
  topic = event[:topic]
  partition = event[:partition]
  seek_offset = event[:message].offset
  consumer = event[:caller]

  info <<~MSG.tr("\n", ' ').strip!
    [#{consumer.id}] Seeking from #{consumer.class}
    on topic #{topic}-#{partition} to offset #{seek_offset}
  MSG
end

#on_dead_letter_queue_dispatched(event) ⇒ Object

Logs info when we have dispatched a message the the DLQ

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 262

def on_dead_letter_queue_dispatched(event)
  consumer = event[:caller]
  topic = consumer.topic.name
  message = event[:message]
  offset = message.offset
  dlq_topic = consumer.topic.dead_letter_queue.topic
  partition = message.partition

  info <<~MSG.tr("\n", ' ').strip!
    [#{consumer.id}] Dispatched message #{offset}
    from #{topic}-#{partition}
    to DLQ topic: #{dlq_topic}
  MSG
end

#on_error_occurred(event) ⇒ Object

There are many types of errors that can occur in many places, but we provide a single handler for all of them to simplify error instrumentation.

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 341

def on_error_occurred(event)
  type = event[:type]
  error = event[:error]
  details = (error.backtrace || []).join("\n")

  case type
  when 'consumer.initialized.error'
    error "Consumer initialized error: #{error}"
    error details
  when 'consumer.wrap.error'
    error "Consumer wrap failed due to an error: #{error}"
    error details
  when 'consumer.consume.error'
    error "Consumer consuming error: #{error}"
    error details
  when 'consumer.revoked.error'
    error "Consumer on revoked failed due to an error: #{error}"
    error details
  when 'consumer.idle.error'
    error "Consumer idle failed due to an error: #{error}"
    error details
  when 'consumer.shutdown.error'
    error "Consumer on shutdown failed due to an error: #{error}"
    error details
  when 'consumer.tick.error'
    error "Consumer on tick failed due to an error: #{error}"
    error details
  when 'consumer.eofed.error'
    error "Consumer on eofed failed due to an error: #{error}"
    error details
  when 'consumer.after_consume.error'
    error "Consumer on after_consume failed due to an error: #{error}"
    error details
  when 'worker.process.error'
    fatal "Worker processing failed due to an error: #{error}"
    fatal details
  when 'connection.listener.fetch_loop.error'
    error "Listener fetch loop error: #{error}"
    error details
  when 'swarm.supervisor.error'
    fatal "Swarm supervisor crashed due to an error: #{error}"
    fatal details
  when 'runner.call.error'
    fatal "Runner crashed due to an error: #{error}"
    fatal details
  when 'app.stopping.error'
    # Counts number of workers and listeners that were still active when forcing the
    # shutdown. Please note, that unless all listeners are closed, workers will not finalize
    # their operations as well.
    # We need to check if listeners and workers are assigned as during super early stages of
    # boot they are not.
    listeners = Server.listeners ? Server.listeners.count(&:active?) : 0
    workers = Server.workers ? Server.workers.count(&:alive?) : 0

    message = <<~MSG.tr("\n", ' ').strip!
      Forceful Karafka server stop with:
      #{workers} active workers and
      #{listeners} active listeners
    MSG

    error message
  when 'app.forceful_stopping.error'
    error "Forceful shutdown error occurred: #{error}"
    error details
  when 'librdkafka.error'
    error "librdkafka internal error occurred: #{error}"
    error details
  # Those can occur when emitted statistics are consumed by the end user and the processing
  # of statistics fails. The statistics are emitted from librdkafka main loop thread and
  # any errors there crash the whole thread
  when 'callbacks.statistics.error'
    error "callbacks.statistics processing failed due to an error: #{error}"
    error details
  when 'callbacks.error.error'
    error "callbacks.error processing failed due to an error: #{error}"
    error details
  # Those will only occur when retries in the client fail and when they did not stop after
  # back-offs
  when 'connection.client.poll.error'
    error "Data polling error occurred: #{error}"
    error details
  when 'connection.client.rebalance_callback.error'
    error "Rebalance callback error occurred: #{error}"
    error details
  when 'connection.client.unsubscribe.error'
    error "Client unsubscribe error occurred: #{error}"
    error details
  when 'parallel_segments.reducer.error'
    error "Parallel segments reducer error occurred: #{error}"
    error details
  when 'parallel_segments.partitioner.error'
    error "Parallel segments partitioner error occurred: #{error}"
    error details
  when 'virtual_partitions.partitioner.error'
    error "Virtual partitions partitioner error occurred: #{error}"
    error details
  # This handles any custom errors coming from places like Web-UI, etc
  else
    error "#{type} error occurred: #{error.class} - #{error}"
    error details
  end
end

#on_filtering_seek(event) ⇒ Object

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 296

def on_filtering_seek(event)
  consumer = event[:caller]
  topic = consumer.topic.name
  # Message to which we seek
  message = event[:message]
  partition = message.partition
  offset = message.offset

  info <<~MSG.tr("\n", ' ').strip!
    [#{consumer.id}] Post-filtering seeking to message #{offset}
    on #{topic}-#{partition}
  MSG
end

#on_filtering_throttled(event) ⇒ Object

Logs info about throttling event

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 280

def on_filtering_throttled(event)
  consumer = event[:caller]
  topic = consumer.topic.name
  # Here we get last message before throttle
  message = event[:message]
  partition = message.partition
  offset = message.offset

  info <<~MSG.tr("\n", ' ').strip!
    [#{consumer.id}] Throttled and will resume
    from message #{offset}
    on #{topic}-#{partition}
  MSG
end

#on_process_notice_signal(event) ⇒ Object

Logs info about system signals that Karafka received and prints backtrace for threads in case of ttin

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 164

def on_process_notice_signal(event)
  server_id = Karafka::Server.id
  info "[#{server_id}] Received #{event[:signal]} system signal"

  # We print backtrace only for ttin
  return unless event[:signal] == :SIGTTIN

  # Inspired by Sidekiq
  Thread.list.each do |thread|
    tid = (thread.object_id ^ ::Process.pid).to_s(36)

    warn "Thread TID-#{tid} #{thread.name}"

    if thread.backtrace
      warn thread.backtrace.join("\n")
    else
      warn '<no backtrace available>'
    end
  end
end

#on_rebalance_partitions_assigned(event) ⇒ Object

Logs info about partitions that we’ve gained

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details with assigned partitions

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 244

def on_rebalance_partitions_assigned(event)
  assigned_partitions = event[:tpl].to_h.transform_values { |part| part.map(&:partition) }
  group_id = event[:consumer_group_id]
  client_id = event[:client_id]
  group_prefix = "[#{client_id}] Group #{group_id} rebalance"

  if assigned_partitions.empty?
    info "#{group_prefix}: No partitions assigned"
  else
    assigned_partitions.each do |topic, partitions|
      info "#{group_prefix}: #{topic}-[#{partitions.join(',')}] assigned"
    end
  end
end

#on_rebalance_partitions_revoked(event) ⇒ Object

Logs info about partitions we have lost

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details with revoked partitions

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 226

def on_rebalance_partitions_revoked(event)
  revoked_partitions = event[:tpl].to_h.transform_values { |part| part.map(&:partition) }
  group_id = event[:consumer_group_id]
  client_id = event[:client_id]
  group_prefix = "[#{client_id}] Group #{group_id} rebalance"

  if revoked_partitions.empty?
    info "#{group_prefix}: No partitions revoked"
  else
    revoked_partitions.each do |topic, partitions|
      info "#{group_prefix}: #{topic}-[#{partitions.join(',')}] revoked"
    end
  end
end

#on_swarm_manager_before_fork(event) ⇒ Object

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 323

def on_swarm_manager_before_fork(event)
  debug "Swarm manager starting node with id: #{event[:node].id}"
end

#on_swarm_manager_control(event) ⇒ Object

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 333

def on_swarm_manager_control(event)
  pids = event[:caller].nodes.map(&:pid).join(', ')
  debug "Swarm manager checking nodes: #{pids}"
end

#on_swarm_manager_stopping(event) ⇒ Object

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 311

def on_swarm_manager_stopping(event)
  node = event[:node]
  error "Swarm manager detected unhealthy node #{node.pid}. Sending TERM signal..."
end

#on_swarm_manager_terminating(event) ⇒ Object

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 317

def on_swarm_manager_terminating(event)
  node = event[:node]
  error "Swarm manager detected unresponsive node #{node.pid}. Sending KILL signal..."
end

#on_swarm_node_after_fork(_event) ⇒ Object

Parameters:

  • _event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 328

def on_swarm_node_after_fork(_event)
  info "Swarm node #{::Process.pid} forked from #{::Process.ppid}"
end

#on_worker_process(event) ⇒ Object

Prints info about the fact that a given job has started

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 73

def on_worker_process(event)
  job = event[:job]
  job_type = job.class.to_s.split('::').last
  consumer = job.executor.topic.consumer
  topic = job.executor.topic.name
  partition = job.executor.partition
  info "[#{job.id}] #{job_type} job for #{consumer} on #{topic}-#{partition} started"
end

#on_worker_processed(event) ⇒ Object

Prints info about the fact that a given job has finished

Parameters:

  • event (Karafka::Core::Monitoring::Event) —

    event details including payload

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# File 'lib/karafka/instrumentation/logger_listener.rb', line 85

def on_worker_processed(event)
  job = event[:job]
  time = event[:time].round(2)
  job_type = job.class.to_s.split('::').last
  consumer = job.executor.topic.consumer
  topic = job.executor.topic.name
  partition = job.executor.partition
  info <<~MSG.tr("\n", ' ').strip!
    [#{job.id}] #{job_type} job for #{consumer}
    on #{topic}-#{partition} finished in #{time} ms
  MSG
end