fluent/fluentd · error · Fluent::ConfigError

Section <label #{name}> appears twice

Error message

Section <label #{name}> appears twice

What it means

Error "Section <label #{name}> appears twice" thrown in fluent/fluentd.

Source

Thrown at lib/fluent/root_agent.rb:427

      input = Plugin.new_input(type)
      # <source> emits events to the top-level event router (RootAgent#event_router).
      # Input#configure overwrites event_router to a label's event_router if it has `@label` parameter.
      # See also 'fluentd/plugin/input.rb'
      input.context_router = @event_router
      input.configure(conf)
      input.event_emitter_apply_source_only if @source_only_mode.enabled?
      if @enable_input_metrics
        @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)

View on GitHub (pinned to dd45c6e18d)

When it happens

Trigger: Thrown at lib/fluent/root_agent.rb:427 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/eca7ec29d10eed32. Report an issue: GitHub.