fluent/fluentd · error · ArgumentError

BUG: max_bytes is available only for udp

Error message

BUG: max_bytes is available only for udp

What it means

Error "BUG: max_bytes is available only for udp" thrown in fluent/fluentd.

Source

Thrown at lib/fluent/plugin_helper/server.rb:152

        raise ArgumentError, "BUG: block not specified which handles received data" unless block_given?
        raise ArgumentError, "BUG: block must have 1 or 2 arguments" unless callback.arity == 1 || callback.arity == 2

        if proto == :tcp || proto == :tls
          socket_options[:linger_timeout] ||= @transport_config&.linger_timeout || 0
        end

        socket_options[:receive_buffer_size] ||= @transport_config&.receive_buffer_size

        unless socket
          socket_option_validate!(proto, **socket_options)
          socket_option_setter = ->(sock){ socket_option_set(sock, **socket_options) }
        end

        if proto != :tcp && proto != :tls && proto != :unix # options to listen/accept connections
          raise ArgumentError, "BUG: backlog is available for tcp/tls" if backlog
        end
        if proto != :udp # UDP options
          raise ArgumentError, "BUG: max_bytes is available only for udp" if max_bytes
          raise ArgumentError, "BUG: flags is available only for udp" if flags != 0
        end

        case proto
        when :tcp
          server = server_create_for_tcp_connection(shared, bind, port, backlog, socket_option_setter) do |conn|
            conn.data(&callback)
          end
        when :tls
          transport_config = if tls_options
                               server_create_transport_section_object(tls_options)
                             elsif @transport_config && @transport_config.protocol == :tls
                               @transport_config
                             else
                               raise ArgumentError, "BUG: TLS transport specified, but certification options are not specified"
                             end
          server = server_create_for_tls_connection(shared, bind, port, transport_config, backlog, socket_option_setter) do |conn|
            conn.data(&callback)

View on GitHub (pinned to dd45c6e18d)

When it happens

Trigger: Thrown at lib/fluent/plugin_helper/server.rb:152 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/65d1d0dbe69eaff6. Report an issue: GitHub.