Class: Fluent::FluentLogEventRouter

Inherits:
NullFluentLogEventRouter show all
Defined in:
lib/fluent/fluent_log_event_router.rb

Overview

This class is for handling fluentd’s inner log e.g. <label @FLUNT_LOG> section and <match fluent.**> section

Constant Summary collapse

STOP = 
:stop
GRACEFUL_STOP = 
:graceful_stop

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from NullFluentLogEventRouter

#emittable?

Constructor Details

#initialize(event_router) ⇒ FluentLogEventRouter

Returns a new instance of FluentLogEventRouter.

Parameters:



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# File 'lib/fluent/fluent_log_event_router.rb', line 87

def initialize(event_router)
  @event_router = event_router
  @thread = nil
  @graceful_stop = false
  @event_queue = Queue.new
end

Class Method Details

.build(root_agent) ⇒ Object

Parameters:



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# File 'lib/fluent/fluent_log_event_router.rb', line 39

def self.build(root_agent)
  log_event_router = nil

  begin
    log_event_agent = root_agent.find_label(Fluent::Log::LOG_EVENT_LABEL)
    log_event_router = log_event_agent.event_router

    # suppress mismatched tags only for <label @FLUENT_LOG> label.
    # it's not suppressed in default event router for non-log-event events
    log_event_router.suppress_missing_match!

    log_event_router = log_event_router

    unmatched_tags = Fluent::Log.event_tags.select { |t| !log_event_router.match?(t) }
    unless unmatched_tags.empty?
      $log.warn "match for some tags of log events are not defined in @FLUENT_LOG label (to be ignored)", tags: unmatched_tags
    end

  rescue ArgumentError # ArgumentError "#{label_name} label not found"
    # use default event router if <label @FLUENT_LOG> is missing in configuration
    root_log_event_router = root_agent.event_router
    event_tags = Fluent::Log.event_tags
    if event_tags.any? { |t| root_log_event_router.match?(t) }
      log_event_router = root_log_event_router

      unmatched_tags = event_tags.select { |t| !log_event_router.match?(t) }
      if unmatched_tags.empty?
        $log.warn "define <match fluent.**> to capture fluentd logs in top level is deprecated. Use <label @FLUENT_LOG> instead"
      else
        matched_sections = (event_tags - unmatched_tags).map { |tag| "<match #{tag}>" }.join(', ')
        $log.warn "define #{matched_sections} to capture fluentd logs in top level is deprecated. Use <label @FLUENT_LOG> instead"
        $log.warn "match for some tags of log events are not defined in top level (to be ignored)", tags: unmatched_tags
      end
    end
  end

  if log_event_router
    FluentLogEventRouter.new(log_event_router)
  else
    $log.debug('No fluent logger for internal event')
    NullFluentLogEventRouter.new
  end
end

Instance Method Details

#emit_event(event) ⇒ Object 



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# File 'lib/fluent/fluent_log_event_router.rb', line 137

def emit_event(event)
  @event_queue.push(event)
end

#graceful_stop ⇒ Object 



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# File 'lib/fluent/fluent_log_event_router.rb', line 131

def graceful_stop
  # to make sure to emit all log events into router, before shutting down
  @event_queue.push(GRACEFUL_STOP)
  @thread && @thread.join
end

#start ⇒ Object 



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# File 'lib/fluent/fluent_log_event_router.rb', line 94

def start
  @thread = Thread.new do
    $log.disable_events(Thread.current)

    loop do
      event = @event_queue.pop

      case event
      when GRACEFUL_STOP
        @graceful_stop = true
      when STOP
        break
      else
        begin
          tag, time, record = event
          @event_router.emit(tag, time, record)
        rescue => e
          # This $log.error doesn't emit log events, because of `$log.disable_events(Thread.current)` above
          $log.error "failed to emit fluentd's log event", tag: tag, event: record, error: e
        end
      end

      if @graceful_stop && @event_queue.empty?
        break
      end
    end
  end

  @thread.abort_on_exception = true
end

#stop ⇒ Object 



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# File 'lib/fluent/fluent_log_event_router.rb', line 125

def stop
  @event_queue.push(STOP)
  # there is no problem calling Thread#join multiple times.
  @thread && @thread.join
end