fluent/fluentd · error · Fluent::ConfigError

'format' parameter is required

Error message

'format' parameter is required

What it means

Error "'format' parameter is required" thrown in fluent/fluentd.

Source

Thrown at lib/fluent/compat/parser.rb:98

          }
        end
      end

      def self.register_template(type, template, time_format=nil)
        # TODO: warn when deprecated to use Plugin.register_parser directly
        if template.is_a?(Class) || template.respond_to?(:call)
          Fluent::Plugin.register_parser(type, template)
        elsif template.is_a?(Regexp)
          Fluent::Plugin.register_parser(type, Proc.new { RegexpParser.new(template, {'time_format' => time_format}) })
        else
          raise ArgumentError, "Template for parser must be a Class, callable object or regular expression object"
        end
      end

      def self.lookup(format)
        # TODO: warn when deprecated to use Plugin.new_parser or RegexpParser.new directly
        if format.nil?
          raise ConfigError, "'format' parameter is required"
        end

        if format[0] == ?/ && format[format.length-1] == ?/
          # regexp
          begin
            regexp = Regexp.new(format[1..-2])
            if regexp.named_captures.empty?
              raise "No named captures"
            end
          rescue
            raise ConfigError, "Invalid regexp '#{format[1..-2]}': #{$!}"
          end

          RegexpParser.new(regexp)
        else
          # built-in template
          begin
            Fluent::Plugin.new_parser(format)

View on GitHub (pinned to dd45c6e18d)

When it happens

Trigger: Thrown at lib/fluent/compat/parser.rb:98 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/9d57ed8c9923a438. Report an issue: GitHub.