fluent/fluentd · error · ArgumentError

BUG: conf must be a Element, Hash (or unspecified), but '#{c

Error message

BUG: conf must be a Element, Hash (or unspecified), but '#{conf.class}'

What it means

Error "BUG: conf must be a Element, Hash (or unspecified), but '#{conf.class}'" thrown in fluent/fluentd.

Source

Thrown at lib/fluent/plugin_helper/storage.rb:67

                   raise Fluent::ConfigError, "@type is required in <storage>" unless conf['@type']
                   conf['@type']
                 elsif default_type
                   default_type
                 else
                   raise ArgumentError, "BUG: both type and conf are not specified"
                 end
          storage = Plugin.new_storage(type, parent: self)
          config = case conf
                   when Fluent::Config::Element
                     conf
                   when Hash
                     # in code, programmer may use symbols as keys, but Element needs strings
                     conf = Hash[conf.map{|k,v| [k.to_s, v]}]
                     Fluent::Config::Element.new('storage', usage, conf, [])
                   when nil
                     Fluent::Config::Element.new('storage', usage, {'@type' => type}, [])
                   else
                     raise ArgumentError, "BUG: conf must be a Element, Hash (or unspecified), but '#{conf.class}'"
                   end
          storage.configure(config)
          if @_storages_started
            storage.start
          end
          s = @_storages[usage] = StorageState.new(wrap_instance(storage), false)
        end

        s.storage
      end

      module StorageParams
        include Fluent::Configurable
        # minimum section definition to instantiate storage plugin instances
        config_section :storage, required: false, multi: true, param_name: :storage_configs, init: true do
          config_argument :usage, :string, default: ''
          config_param    :@type, :string, default: Fluent::Plugin::Storage::DEFAULT_TYPE
        end

View on GitHub (pinned to dd45c6e18d)

When it happens

Trigger: Thrown at lib/fluent/plugin_helper/storage.rb:67 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/90b690e53c766125. Report an issue: GitHub.