Class: Clacky::Server::HttpServer::WebSocketConnection

Inherits:
Object
  • Object
show all
Defined in:
lib/clacky/server/http_server.rb

Overview

Wraps a raw TCP socket, providing thread-safe WebSocket frame sending.

IMPORTANT: send_raw is called from the Agent thread via broadcast() → send_json(). A blocking socket write with no deadline can pin the Agent thread indefinitely when the client's receive buffer fills up (silent disconnects such as Wi-Fi handoff or NAT timeout, where TCP keepalive defaults are measured in hours). Thread#raise on blocking native socket writes is best-effort and unreliable, so instead we bound every write with an explicit deadline using IO.select + write_nonblock and declare the connection dead on timeout.

Constant Summary collapse

SEND_DEADLINE =

Maximum time a single send_raw call is allowed to spend writing. 5 seconds is generous for healthy LAN/Internet clients and short enough that a stuck Agent becomes responsive again quickly.

5.0
SEND_SLOW_WARN =

Warn threshold — any individual send_raw that exceeds this is logged so we can spot sluggish clients before they fully hang.

1.0

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(socket, version) ⇒ WebSocketConnection

Returns a new instance of WebSocketConnection.



7489
7490
7491
7492
7493
7494
7495
 
# File 'lib/clacky/server/http_server.rb', line 7489

def initialize(socket, version)
  @socket     = socket
  @version    = version
  @send_mutex = Mutex.new
  @closed     = false
  WebSocketConnection.apply_keepalive(socket)
end

Instance Attribute Details

#session_id ⇒ Object

Returns the value of attribute session_id.



7478
7479
7480
 
# File 'lib/clacky/server/http_server.rb', line 7478

def session_id
  @session_id
end

Class Method Details

.apply_keepalive(socket) ⇒ Object

Enable TCP keepalive on the underlying socket so silently dead peers are detected in minutes instead of the OS default of hours. Best-effort: any failure is logged at debug level and ignored.



7609
7610
7611
7612
7613
7614
7615
7616
7617
7618
7619
7620
7621
7622
7623
7624
7625
7626
7627
7628
7629
7630
7631
7632
7633
7634
7635
 
# File 'lib/clacky/server/http_server.rb', line 7609

def self.apply_keepalive(socket)
  return unless socket.respond_to?(:setsockopt)

  socket.setsockopt(Socket::SOL_SOCKET, Socket::SO_KEEPALIVE, true)

  # TCP-level keepalive tuning — constants vary by platform and are
  # only set when available. Values chosen to detect dead peers in
  # roughly 60-90 seconds total.
  if defined?(Socket::IPPROTO_TCP)
    # Idle time before first probe (Linux: TCP_KEEPIDLE, macOS: TCP_KEEPALIVE)
    idle_const = if Socket.const_defined?(:TCP_KEEPIDLE)
                   Socket::TCP_KEEPIDLE
                 elsif Socket.const_defined?(:TCP_KEEPALIVE)
                   Socket::TCP_KEEPALIVE
                 end
    socket.setsockopt(Socket::IPPROTO_TCP, idle_const, 60) if idle_const

    if Socket.const_defined?(:TCP_KEEPINTVL)
      socket.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_KEEPINTVL, 10)
    end
    if Socket.const_defined?(:TCP_KEEPCNT)
      socket.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_KEEPCNT, 3)
    end
  end
rescue StandardError => e
  Clacky::Logger.debug("[WS] failed to set keepalive: #{e.class}: #{e.message}")
end

Instance Method Details

#closed? ⇒ Boolean

Returns true if the underlying socket has been detected as dead.

Returns:

  • (Boolean) 


7498
7499
7500
 
# File 'lib/clacky/server/http_server.rb', line 7498

def closed?
  @closed
end

#force_close! ⇒ Object

Force-close the connection (used by the interrupt watchdog when an Agent thread is stuck on an unresponsive socket write).



7504
7505
7506
7507
7508
7509
 
# File 'lib/clacky/server/http_server.rb', line 7504

def force_close!
  @closed = true
  @socket.close
rescue StandardError
  # best effort
end

#send_json(data) ⇒ Object

Send a JSON-serializable object over the WebSocket. Returns true on success, false if the connection is dead.



7513
7514
7515
7516
7517
7518
 
# File 'lib/clacky/server/http_server.rb', line 7513

def send_json(data)
  send_raw(:text, JSON.generate(data))
rescue => e
  Clacky::Logger.debug("WS send error (connection dead): #{e.message}")
  false
end

#send_raw(type, data) ⇒ Object

Send a raw WebSocket frame. Returns true on success, false on broken/closed/sluggish socket.

Uses write_nonblock with an overall deadline so the caller (typically the Agent thread) never blocks longer than SEND_DEADLINE, even if the client silently stopped reading.



7526
7527
7528
7529
7530
7531
7532
7533
7534
7535
7536
7537
7538
7539
7540
7541
7542
7543
7544
7545
7546
7547
7548
7549
7550
7551
7552
7553
7554
7555
7556
7557
7558
7559
7560
7561
7562
7563
7564
7565
7566
7567
7568
7569
7570
7571
 
# File 'lib/clacky/server/http_server.rb', line 7526

def send_raw(type, data)
  started_at = Process.clock_gettime(Process::CLOCK_MONOTONIC)

  @send_mutex.synchronize do
    return false if @closed

    outgoing = WebSocket::Frame::Outgoing::Server.new(
      version: @version,
      data: data,
      type: type
    )
    bytes = outgoing.to_s

    unless write_with_deadline(bytes, SEND_DEADLINE)
      # Deadline exceeded — treat as a dead connection so broadcast
      # purges it and the Agent thread is freed immediately.
      @closed = true
      begin
        @socket.close
      rescue StandardError
        # ignore
      end
      Clacky::Logger.warn(
        "[WS] send_raw deadline exceeded — closing sluggish connection " \
        "(bytes=#{bytes.bytesize}, deadline=#{SEND_DEADLINE}s)"
      )
      return false
    end
  end

  elapsed = Process.clock_gettime(Process::CLOCK_MONOTONIC) - started_at
  if elapsed > SEND_SLOW_WARN
    Clacky::Logger.warn(
      "[WS] send_raw slow: #{elapsed.round(2)}s (type=#{type})"
    )
  end
  true
rescue Errno::EPIPE, Errno::ECONNRESET, IOError, Errno::EBADF => e
  @closed = true
  Clacky::Logger.debug("WS send_raw error (client disconnected): #{e.message}")
  false
rescue => e
  @closed = true
  Clacky::Logger.debug("WS send_raw unexpected error: #{e.message}")
  false
end