PyBridge

Moose Development/Moose/Python/MooseBridgeSocketTuningExtension.lua

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+-- Optional connection tuning extension for MOOSE Bridge.
+--
+-- Load after MooseBridge.lua and before creating the bridge instance. It reduces
+-- DCS main-thread stalls when the Python server is not running by shortening the
+-- blocking LuaSocket connect timeout and using less aggressive retry defaults.
+
+if not MOOSE_BRIDGE then error("Load MooseBridge.lua before MooseBridgeSocketTuningExtension.lua") end
+
+local function bridge_tuning_mission_time()
+  if timer and timer.getTime then return timer.getTime() end
+  return 0
+end
+
+local function bridge_tuning_safe_tostring(value)
+  if value == nil then return "nil" end
+  return tostring(value)
+end
+
+local function bridge_should_log_connect_failure(bridge, err, now)
+  if bridge.LogConnectFailures == false then return false end
+  if err == "timeout" and bridge.LogConnectTimeouts ~= true then return false end
+
+  local interval = bridge.ConnectFailureLogInterval or 60
+  if bridge.LastConnectFailureLog and now - bridge.LastConnectFailureLog < interval then return false end
+
+  bridge.LastConnectFailureLog = now
+  return true
+end
+
+local _moose_bridge_tuning_base_new = MOOSE_BRIDGE.New
+
+function MOOSE_BRIDGE:New(host, port)
+  local bridge = _moose_bridge_tuning_base_new(self, host, port)
+
+  -- Keep idle bridge retries low-impact when the Python server is not listening.
+  bridge.ConnectTimeout = bridge.ConnectTimeout or 0.02
+  if bridge.ConnectRetryDelay == nil or bridge.ConnectRetryDelay == 5 then bridge.ConnectRetryDelay = 10 end
+  if bridge.TickInterval == nil or bridge.TickInterval == 0.2 then bridge.TickInterval = 0.5 end
+  if bridge.HeartbeatInterval == nil or bridge.HeartbeatInterval == 5 then bridge.HeartbeatInterval = 10 end
+
+  -- Keep expected idle reconnect timeouts out of dcs.log by default.
+  if bridge.LogConnectFailures == nil then bridge.LogConnectFailures = true end
+  if bridge.LogConnectTimeouts == nil then bridge.LogConnectTimeouts = false end
+  bridge.ConnectFailureLogInterval = bridge.ConnectFailureLogInterval or 60
+  bridge.LastConnectFailureLog = nil
+
+  return bridge
+end
+
+function MOOSE_BRIDGE:_Connect()
+  local now = bridge_tuning_mission_time()
+  if now - self.LastConnectAttempt < (self.ConnectRetryDelay or 10) then return end
+  self.LastConnectAttempt = now
+
+  local lib = require("socket")
+  local conn = lib.tcp()
+  conn:settimeout(self.ConnectTimeout or 0.02)
+
+  local ok, err = conn:connect(self.Host, self.Port)
+  if not ok then
+    if bridge_should_log_connect_failure(self, err, now) then
+      self:_Log("Connect failed: " .. bridge_tuning_safe_tostring(err))
+    end
+    conn:close()
+    return
+  end
+
+  -- All regular bridge IO is polled from the scheduler tick and must not block DCS.
+  conn:settimeout(0)
+  self.Socket = conn
+  self.Connected = true
+  self:_Log("Connected to Python bridge")
+end