add skynet.watch for skynet.call, read http://blog.codingnow.com/2013/12/skynet_monitor.html

lualib/skynet.lua

@@ -26,9 +26,56 @@ local session_coroutine_address = {}
 local wakeup_session = {}
 local sleep_session = {}
 
+local watching_service = {}
+local watching_session = {}
+local exit_queue = {}
+
+-- suspend is function
+local suspend
+
 local trace_handle
 local trace_func = function() end
 
+local function string_to_handle(str)
+	return tonumber("0x" .. string.sub(str , 2))
+end
+
+----- monitor exit
+
+local function dispatch_exit()
+	local session = table.remove(exit_queue,1)
+	if session then
+		local co = session_id_coroutine[session]
+		session_id_coroutine[session] = nil
+		return suspend(co, coroutine.resume(co, false))
+	end
+end
+
+local function _exit_dispatch(session, monitor, service)
+--  Don't remove from watching_service , because user may call dead service
+	watching_service[service] = false
+	for session, srv in pairs(watching_session) do
+		if srv == service then
+			table.insert(exit_queue, session)
+		end
+	end
+end
+
+local watch_monitor
+
+function skynet.watch(service)
+	assert(type(service) == "number")
+	if watch_monitor == nil then
+		watch_monitor = string_to_handle(c.command("MONITOR"))
+		assert(watch_monitor, "Need a monitor")
+	end
+	if watching_service[service] == nil then
+		watching_service[service] = true
+		-- read lualib/simplemonitor.lua
+		assert(skynet.call(watch_monitor, "lua", "WATCH", service), "watch a dead service")
+	end
+end
+
 -- coroutine reuse
 
 local coroutine_pool = {}
@@ -52,9 +99,6 @@ local function co_create(f)
 	return co
 end
 
--- suspend is function
-local suspend
-
 local function dispatch_wakeup()
 	local co = next(wakeup_session)
 	if co then
@@ -111,6 +155,7 @@ function suspend(co, result, command, param, size)
 	end
 	trace_count()
 	dispatch_wakeup()
+	dispatch_exit()
 end
 
 function skynet.timeout(ti, func)
@@ -155,10 +200,6 @@ function skynet.name(name, handle)
 	c.command("NAME", name .. " " .. handle)
 end
 
-local function string_to_handle(str)
-	return tonumber("0x" .. string.sub(str , 2))
-end
-
 local self_handle
 function skynet.self()
 	if self_handle then
@@ -210,6 +251,9 @@ end
 
 function skynet.send(addr, typename, ...)
 	local p = proto[typename]
+	if watching_service[addr] == false then
+		error("Service is dead")
+	end
 	return c.send(addr, p.id, 0 , p.pack(...))
 end
 
@@ -231,10 +275,21 @@ skynet.pack = assert(c.pack)
 skynet.unpack = assert(c.unpack)
 skynet.tostring = assert(c.tostring)
 
+local function yield_call(service, session)
+	watching_session[session] = service
+	local succ, msg, sz = coroutine_yield("CALL", session)
+	watching_session[session] = nil
+	assert(succ, "Service is dead")
+	return msg,sz
+end
+
 function skynet.call(addr, typename, ...)
 	local p = proto[typename]
-	local session = c.send(addr, p.id , nil , p.pack(...))
-	return p.unpack(coroutine_yield("CALL", assert(session, "call to invalid address")))
+	if watching_service[addr] == false then
+		error("Service is dead")
+	end
+	local session = assert(c.send(addr, p.id , nil , p.pack(...)),"call to invalid address")
+	return p.unpack(yield_call(addr, session))
 end
 
 function skynet.blockcall(addr, typename , ...)
@@ -245,13 +300,13 @@ function skynet.blockcall(addr, typename , ...)
 		c.command("UNLOCK")
 		error("call to invalid address")
 	end
-	return p.unpack(coroutine_yield("CALL", session))
+	return p.unpack(yield_call(addr, session))
 end
 
 function skynet.rawcall(addr, typename, msg, sz)
 	local p = proto[typename]
-	local session = c.send(addr, p.id , nil , msg, sz)
-	return coroutine_yield("CALL", assert(session, "call to invalid address"))
+	local session = assert(c.send(addr, p.id , nil , msg, sz), "call to invalid address")
+	return yield_call(addr, session)
 end
 
 function skynet.ret(msg, sz)
@@ -306,7 +361,7 @@ local function raw_dispatch_message(prototype, msg, sz, session, source, ...)
 		else
 			c.trace_switch(trace_handle, session)
 			session_id_coroutine[session] = nil
-			suspend(co, coroutine.resume(co, msg, sz))
+			suspend(co, coroutine.resume(co, true, msg, sz))
 		end
 	else
 		local p = assert(proto[prototype], prototype)
@@ -419,7 +474,6 @@ do
 	local remote_call_func = setmetatable({}, weak_meta)
 
 	local _send = assert(c.send)
-	local _yield = coroutine.yield
 	local _pack = assert(c.pack)
 	local _unpack = assert(c.unpack)
 	local _local = skynet.self()
@@ -431,7 +485,7 @@ do
 				local addr = remote_query(t.__remote)
 				-- the proto is 11 (lua is 10)
 				local session = assert(_send(addr, 11 , nil, _pack(t,method,...)), "call to invalid address")
-				local msg, sz = _yield("CALL", session)
+				local msg, sz = coroutine_yield(session)
 				return select(2,assert(_unpack(msg,sz)))
 			end
 			remote_call_func[method] = f
@@ -463,13 +517,13 @@ do
 
 	local function remote_call(obj, method, ...)
 		if type(obj) ~= "table" or type(method) ~= "string" then
-			return _yield("RETURN", _pack(false, "Invalid call"))
+			return coroutine_yield("RETURN", _pack(false, "Invalid call"))
 		end
 		local f = obj[method]
 		if type(f) ~= "function" then
-			return _yield("RETURN", _pack(false, "Object has not method " .. method))
+			return coroutine_yield("RETURN", _pack(false, "Object has not method " .. method))
 		end
-		return _yield("RETURN", _pack(pcall(f,...)))
+		return coroutine_yield("RETURN", _pack(pcall(f,...)))
 	end
 
 	function skynet.remote_root()
@@ -575,6 +629,14 @@ do
 		unpack = skynet.unpack,
 		dispatch = _debug_dispatch,
 	}
+
+	REG {
+		name = "exit",
+		id = 7,
+		pack = skynet.pack,
+		unpack = skynet.unpack,
+		dispatch = _exit_dispatch,
+	}
 end
 
 local init_func = {}

service/pingserver.lua

@@ -11,6 +11,10 @@ function command.HELLO()
 	skynet.ret(skynet.pack("hello"))
 end
 
+function command.EXIT()
+	skynet.exit()
+end
+
 skynet.start(function()
 	skynet.dispatch("lua", function(session,addr, cmd, ...)
 		command[cmd](...)

service/simplemonitor.lua

@@ -2,13 +2,39 @@ local skynet = require "skynet"
 
 -- It's a simple service exit monitor, you can do something more when a service exit.
 
+local service_map = {}
+
 skynet.register_protocol {
 	name = "client",
 	id = 3,
 	unpack = function() end,
 	dispatch = function(_, address)
+		local w = service_map[address]
+		if w then
+			for watcher in pairs(w) do
+				skynet.send(watcher, "exit", address)
+			end
+			service_map[address] = false
+		end
 		print(string.format("[:%x] exit", address))
 	end
 }
 
-skynet.start(function() end)
+local function monitor(session, watcher, command, service)
+	assert(command, "WATCH")
+	local w = service_map[service]
+	if not w then
+		if w == false then
+			skynet.ret(skynet.pack(false))
+			return
+		end
+		w = {}
+		service_map[service] = w
+	end
+	w[watcher] = true
+	skynet.ret(skynet.pack(true))
+end
+
+skynet.start(function()
+	skynet.dispatch("lua", monitor)
+end)

service/testping.lua

@@ -0,0 +1,9 @@
+local skynet = require "skynet"
+
+skynet.start(function()
+	local ps = skynet.uniqueservice("pingserver")
+	skynet.watch(ps)
+	print(skynet.call(ps, "lua", "PING", "hello"))
+	skynet.send(ps, "lua", "EXIT")
+	print(skynet.call(ps, "lua", "PING", "hay"))
+end)

skynet-src/skynet.h

@@ -11,8 +11,8 @@
 #define PTYPE_SYSTEM 4
 #define PTYPE_HARBOR 5
 #define PTYPE_SOCKET 6
-// don't use these id
-#define PTYPE_RESERVED_0 7	
+// read lualib/skynet.lua lualib/simplemonitor.lua
+#define PTYPE_EXIT 7	
 // read lualib/skynet.lua lualib/mqueue.lua
 #define PTYPE_RESERVED_QUEUE 8
 #define PTYPE_RESERVED_DEBUG 9

skynet-src/skynet_server.c

@@ -540,7 +540,12 @@ skynet_command(struct skynet_context * context, const char * cmd , const char *
 	if (strcmp(cmd,"MONITOR") == 0) {
 		uint32_t handle=0;
 		if (param == NULL || param[0] == '\0') {
-			handle = context->handle;
+			if (G_NODE.monitor_exit) {
+				// return current monitor serivce
+				sprintf(context->result, ":%x", G_NODE.monitor_exit);
+				return context->result;
+			}
+			return NULL;
 		} else {
 			if (param[0] == ':') {
 				handle = strtoul(param+1, NULL, 16);