fluent/fluentd · error · Fluent::ConfigError

Missing symbol argument on <label> directive

Error message

Missing symbol argument on <label> directive

What it means

Error "Missing symbol argument on <label> directive" thrown in fluent/fluentd.

Source

Thrown at lib/fluent/root_agent.rb:170

              raise Fluent::ConfigError, "<worker> section cannot have <#{elem.name}> directive"
            end
            elem.set_target_worker_id(target_worker_id)
          end
        end
        conf += e
      end
      conf.elements.delete_if{|e| e.name == 'worker'}

      error_label_config = nil

      # initialize <label> elements before configuring all plugins to avoid 'label not found' in input, filter and output.
      label_configs = {}
      conf.elements(name: 'label').each { |e|
        if !Fluent::Engine.supervisor_mode && e.for_another_worker?
          next
        end
        name = e.arg
        raise ConfigError, "Missing symbol argument on <label> directive" if name.empty?
        raise ConfigError, "@ROOT for <label> is not permitted, reserved for getting root router" if name == '@ROOT'

        if name == ERROR_LABEL
          error_label_config = e
        else
          add_label(name)
          label_configs[name] = e
        end
      }
      # Call 'configure' here to avoid 'label not found'
      label_configs.each { |name, e| @labels[name].configure(e) }
      setup_error_label(error_label_config) if error_label_config

      super

      setup_source_only_buffer_agent if @source_only_mode.enabled?

      # initialize <source> elements

View on GitHub (pinned to dd45c6e18d)

When it happens

Trigger: Thrown at lib/fluent/root_agent.rb:170 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/afdfafa3dfd79500. Report an issue: GitHub.