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.



6531
6532
6533
6534
6535
6536
6537
 
# File 'lib/clacky/server/http_server.rb', line 6531

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.



6520
6521
6522
 
# File 'lib/clacky/server/http_server.rb', line 6520

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.



6651
6652
6653
6654
6655
6656
6657
6658
6659
6660
6661
6662
6663
6664
6665
6666
6667
6668
6669
6670
6671
6672
6673
6674
6675
6676
6677
 
# File 'lib/clacky/server/http_server.rb', line 6651

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) 


6540
6541
6542
 
# File 'lib/clacky/server/http_server.rb', line 6540

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).



6546
6547
6548
6549
6550
6551
 
# File 'lib/clacky/server/http_server.rb', line 6546

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.



6555
6556
6557
6558
6559
6560
 
# File 'lib/clacky/server/http_server.rb', line 6555

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.



6568
6569
6570
6571
6572
6573
6574
6575
6576
6577
6578
6579
6580
6581
6582
6583
6584
6585
6586
6587
6588
6589
6590
6591
6592
6593
6594
6595
6596
6597
6598
6599
6600
6601
6602
6603
6604
6605
6606
6607
6608
6609
6610
6611
6612
6613
 
# File 'lib/clacky/server/http_server.rb', line 6568

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