fluent/fluentd · error · ArgumentError

BUG: socket option is available only for udp

Error message

BUG: socket option is available only for udp

What it means

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

Source

Thrown at lib/fluent/plugin_helper/server.rb:131

      # server_create(:title, @port) do |data|
      #   # ...
      # end
      # server_create(:title, @port) do |data, conn|
      #   # ...
      # end
      # server_create(:title, @port, proto: :udp, max_bytes: 2048) do |data, sock|
      #   sock.remote_host
      #   sock.remote_port
      #   # ...
      # end
      def server_create(title, port, proto: nil, bind: '0.0.0.0', shared: true, socket: nil, backlog: nil, tls_options: nil, max_bytes: nil, flags: 0, **socket_options, &callback)
        proto ||= (@transport_config && @transport_config.protocol == :tls) ? :tls : :tcp

        raise ArgumentError, "BUG: title must be a symbol" unless title && title.is_a?(Symbol)
        raise ArgumentError, "BUG: port must be an integer" unless port && port.is_a?(Integer)
        raise ArgumentError, "BUG: invalid protocol name" unless PROTOCOLS.include?(proto)

        raise ArgumentError, "BUG: socket option is available only for udp" if socket && proto != :udp
        raise ArgumentError, "BUG: tls_options is available only for tls" if tls_options && proto != :tls

        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

View on GitHub (pinned to dd45c6e18d)

When it happens

Trigger: Thrown at lib/fluent/plugin_helper/server.rb:131 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/057519a8329ca9fb. Report an issue: GitHub.