fluent/fluentd · error · ArgumentError

#{label_name} label not found

Error message

#{label_name} label not found

What it means

Error "#{label_name} label not found" thrown in fluent/fluentd.

Source

Thrown at lib/fluent/root_agent.rb:436

        @event_router.add_metric_callbacks(input.plugin_id, Proc.new {|es| input.metric_callback(es) })
      end
      @inputs << input

      input
    end

    def add_label(name)
      label = Label.new(name, log: log)
      raise ConfigError, "Section <label #{name}> appears twice" if @labels[name]
      label.root_agent = self
      @labels[name] = label
    end

    def find_label(label_name)
      if label = @labels[label_name]
        label
      else
        raise ArgumentError, "#{label_name} label not found"
      end
    end

    def emit_error_event(tag, time, record, error)
      error_info = {error: error, location: (error.backtrace ? error.backtrace.first : nil), tag: tag, time: time}
      if @error_collector
        # A record is not included in the logs because <@ERROR> handles it. This warn is for the notification
        log.warn "send an error event to @ERROR:", error_info
        @error_collector.emit(tag, time, record)
      else
        error_info[:record] = record
        log.warn "dump an error event:", error_info
      end
    end

    def handle_emits_error(tag, es, error)
      error_info = {error: error, location: (error.backtrace ? error.backtrace.first : nil), tag: tag}
      if @error_collector

View on GitHub (pinned to dd45c6e18d)

When it happens

Trigger: Thrown at lib/fluent/root_agent.rb:436 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of fluent/fluentd@dd45c6e18d (2026-08-21). Data as JSON: /api/errors/1fc82380c809e2cc. Report an issue: GitHub.