add socketchannel.overload

lualib/skynet/db/mongo.lua

@@ -173,6 +173,7 @@ function mongo.client( conf	)
 		auth = mongo_auth(obj),
 		backup = backup,
 		nodelay = true,
+		overload = conf.overload,
 	}
 	setmetatable(obj, client_meta)
 	obj.__sock:connect(true)	-- try connect only	once

lualib/skynet/db/mysql.lua

@@ -21,26 +21,17 @@ local sha1= crypt.sha1
 local setmetatable = setmetatable
 local error = error
 local tonumber = tonumber
-local    new_tab = function (narr, nrec) return {} end
+local new_tab = function (narr, nrec) return {} end
 
 
-local _M = { _VERSION = '0.13' }
+local _M = { _VERSION = '0.14' }
 -- constants
 
-local STATE_CONNECTED = 1
-local STATE_COMMAND_SENT = 2
-
 local COM_QUERY = 0x03
-
 local SERVER_MORE_RESULTS_EXISTS = 8
 
--- 16MB - 1, the default max allowed packet size used by libmysqlclient
-local FULL_PACKET_SIZE = 16777215
-
-
 local mt = { __index = _M }
 
-
 -- mysql field value type converters
 local converters = new_tab(0, 8)
 
@@ -640,6 +631,7 @@ function _M.connect(opts)
         host = opts.host,
         port = opts.port or 3306,
         auth = _mysql_login(self,user,password,database,opts.on_connect),
+		overload = opts.overload,
     }
     self.sockchannel = channel
     -- try connect first only once

lualib/skynet/db/redis.lua

@@ -143,6 +143,7 @@ function redis.connect(db_conf)
 		port = db_conf.port or 6379,
 		auth = redis_login(db_conf.auth, db_conf.db),
 		nodelay = true,
+		overload = db_conf.overload,
 	}
 	-- try connect first only once
 	channel:connect(true)

lualib/skynet/socketchannel.lua

@@ -39,6 +39,8 @@ function socket_channel.channel(desc)
 		__closed = false,
 		__authcoroutine = false,
 		__nodelay = desc.nodelay,
+		__overload_notify = desc.overload,
+		__overload = false,
 	}
 
 	return setmetatable(c, channel_meta)
@@ -246,6 +248,32 @@ local function connect_once(self)
 		socketdriver.nodelay(fd)
 	end
 
+	-- register overload warning
+
+	local overload = self.__overload_notify
+	if overload then
+		local function overload_trigger(id, size)
+			if id == self.__sock[1] then
+				if size == 0 then
+					if self.__overload then
+						self.__overload = false
+						overload(false)
+					end
+				else
+					if not self.__overload then
+						self.__overload = true
+						overload(true)
+					else
+						skynet.error(string.format("WARNING: %d K bytes need to send out (fd = %d %s:%s)", size, id, self.__host, self.__port))
+					end
+				end
+			end
+		end
+
+		skynet.fork(overload_trigger, fd, 0)
+		socket.warning(fd, overload_trigger)
+	end
+
 	while self.__dispatch_thread do
 		-- wait for dispatch thread exit
 		skynet.yield()