natsbot

commit 11b3993073836cde41eccd31206922b663789e5d
parent 843fe7b869909148418c763711c16e3e6ec78462
Author: Natasha Kerensikova <natgh@instinctive.eu>
Date:   Wed, 24 Sep 2025 18:07:16 +0000

Subscriptions are reused on reload
Diffstat:
M
natsbot.go
 | 
51
++++++++++++++++++++++++++++++++++++++++++++++++++-

1 file changed, 50 insertions(+), 1 deletion(-)
diff --git a/natsbot.go b/natsbot.go
@@ -223,6 +223,7 @@ const (
 	keyTimerTable
 	keyReloadRequest
 	keyOldCfgMap
+	keyOldSubsCfgMap
 )
 
 func registerState(L *lua.LState, evtChan chan *internalEvent, msgChan chan *nats.Msg) {
@@ -243,9 +244,11 @@ func stateReloadBegin(oldL, newL *lua.LState) {
 	evtChan := stateEvtChan(oldL)
 	msgChan := stateMsgChan(oldL)
 	cfgMap := stateCfgMap(oldL)
+	subsCfgMap := stateSubsCfgMap(oldL)
 
 	registerState(newL, evtChan, msgChan)
 	newL.RawSetInt(stateGet(newL), keyOldCfgMap, newUserData(newL, cfgMap))
+	newL.RawSetInt(stateGet(newL), keyOldSubsCfgMap, newUserData(newL, subsCfgMap))
 }
 
 func stateReloadAbort(oldL, newL *lua.LState) {
@@ -255,18 +258,22 @@ func stateReloadAbort(oldL, newL *lua.LState) {
 func stateReloadEnd(oldL, newL *lua.LState) {
 	stateClean(oldL, newL)
 	newL.RawSetInt(stateGet(newL), keyOldCfgMap, lua.LNil)
+	newL.RawSetInt(stateGet(newL), keyOldSubsCfgMap, lua.LNil)
 }
 
 func stateClean(L, keptL *lua.LState) {
 	_, connIdx := stateConnTable(L)
+	_, subsIdx := stateSubsTable(L)
 
 	st := stateGet(L)
 	L.RawSetInt(st, keyConnTable, newConnTbl(L))
 	L.RawSetInt(st, keySubsTable, newSubsTbl(L))
 
 	var keptConn connMap
+	var keptSubs subsMap
 	if keptL != nil {
 		_, keptConn = stateConnTable(keptL)
+		_, keptSubs = stateSubsTable(keptL)
 	}
 
 	for nc := range connIdx {
@@ -281,6 +288,18 @@ func stateClean(L, keptL *lua.LState) {
 		nc.SetReconnectHandler(nil)
 		nc.Close()
 	}
+
+	for ns := range subsIdx {
+		if _, found := keptSubs[ns]; found {
+			continue
+		}
+
+		if ns.IsValid() {
+			if err := ns.Unsubscribe(); err != nil {
+				log.Println("Unsubscribe:", err)
+			}
+		}
+	}
 }
 
 func stateUncheckedGet(L *lua.LState) *lua.LTable {
@@ -402,6 +421,33 @@ func deleteFromSubsCfgMap(L *lua.LState, s *nats.Subscription) {
 	}
 }
 
+func findInOldSubsCfgMap(L *lua.LState, nc *nats.Conn, key subsCfg) *nats.Subscription {
+	ud := stateValue(L, keyOldSubsCfgMap)
+	if ud == lua.LNil {
+		return nil
+	}
+
+	cMap, found := ud.(*lua.LUserData).Value.(subsCfgMap)[key]
+	if !found {
+		return nil
+	}
+
+	subsArray, found := cMap[nc]
+	if !found {
+		return nil
+	}
+
+	_, knownSubsMap := stateSubsTable(L)
+	for _, s := range subsArray {
+		_, found = knownSubsMap[s]
+		if !found {
+			return s
+		}
+	}
+
+	return nil
+}
+
 /********** NATS Connection Configuration **********/
 
 type natsConfig struct {
@@ -724,7 +770,10 @@ func natsSubscribe(L *lua.LState) int {
 	subject := L.CheckString(2)
 	fn := L.CheckFunction(3)
 
-	if s, err := nc.ChanSubscribe(subject, stateMsgChan(L)); err != nil {
+	if s := findInOldSubsCfgMap(L, nc, subsCfg{subject: subject}); s != nil {
+		L.Push(wrapSubs(L, fn, s, nc))
+		return 1
+	} else if s, err := nc.ChanSubscribe(subject, stateMsgChan(L)); err != nil {
 		log.Println("Subscribe:", err)
 		L.Push(lua.LNil)
 		L.Push(lua.LString(err.Error()))