fluent/fluentd · error · Fluent::ConfigError

Invalid regexp '#{format[1..-2]}': #{$!}

Error message

Invalid regexp '#{format[1..-2]}': #{$!}

What it means

Error "Invalid regexp '#{format[1..-2]}': #{$!}" thrown in fluent/fluentd.

Source

Thrown at lib/fluent/compat/parser.rb:109

          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)
          rescue ConfigError # keep same error message
            raise ConfigError, "Unknown format template '#{format}'"
          end
        end
      end

      module TypeConverterCompatParameters
        def convert_type_converter_parameters!(conf)
          if conf["types"]
            delimiter = conf["types_delimiter"] || ','
            label_delimiter = conf["types_label_delimiter"] || ':'

View on GitHub (pinned to dd45c6e18d)

When it happens

Trigger: Thrown at lib/fluent/compat/parser.rb:109 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/90133d4dc9af8a7b. Report an issue: GitHub.