Prevent race conditions in live query socket notifications

db/db.go

@@ -66,9 +66,11 @@ func Exit() (err error) {
 
 	log.WithPrefix("db").Infof("Gracefully shutting down database")
 
-	for id, so := range sockets {
+	sockets.Range(func(key, val interface{}) bool {
+		id, so := key.(string), val.(*socket)
 		deregister(so.fibre, id)()
-	}
+		return true
+	})
 
 	return db.Close()
 

db/live.go

@@ -23,25 +23,16 @@ import (
 	"github.com/abcum/surreal/sql"
 )
 
-var locker sync.Mutex
-
-var sockets map[string]*socket
-
-func init() {
-	sockets = make(map[string]*socket)
-}
+var sockets sync.Map
 
 func register(fib *fibre.Context, id string) func() {
 	return func() {
 
-		locker.Lock()
-		defer locker.Unlock()
-
-		sockets[id] = &socket{
+		sockets.LoadOrStore(id, &socket{
 			fibre: fib,
 			items: make(map[string][]interface{}),
 			lives: make(map[string]*sql.LiveStatement),
-		}
+		})
 
 	}
 }
@@ -49,11 +40,8 @@ func register(fib *fibre.Context, id string) func() {
 func deregister(fib *fibre.Context, id string) func() {
 	return func() {
 
-		locker.Lock()
-		defer locker.Unlock()
-
-		if sck, ok := sockets[id]; ok {
-			sck.deregister(id)
+		if sck, ok := sockets.Load(id); ok {
+			sck.(*socket).deregister(id)
 		}
 
 	}
@@ -63,8 +51,8 @@ func (e *executor) executeLive(ctx context.Context, stm *sql.LiveStatement) (out
 
 	stm.FB = ctx.Value(ctxKeyId).(string)
 
-	if sck, ok := sockets[stm.FB]; ok {
-		return sck.executeLive(e, ctx, stm)
+	if sck, ok := sockets.Load(stm.FB); ok {
+		return sck.(*socket).executeLive(e, ctx, stm)
 	}
 
 	return nil, &QueryError{}
@@ -75,8 +63,8 @@ func (e *executor) executeKill(ctx context.Context, stm *sql.KillStatement) (out
 
 	stm.FB = ctx.Value(ctxKeyId).(string)
 
-	if sck, ok := sockets[stm.FB]; ok {
-		return sck.executeKill(e, ctx, stm)
+	if sck, ok := sockets.Load(stm.FB); ok {
+		return sck.(*socket).executeKill(e, ctx, stm)
 	}
 
 	return nil, &QueryError{}

db/lives.go

@@ -51,13 +51,15 @@ func (d *document) lives(ctx context.Context, when method) (err error) {
 
 		for _, lv := range lvs {
 
-			var ok bool
-			var con *socket
-			var out interface{}
+			if sck, ok := sockets.Load(lv.FB); ok {
 
-			if con, ok = sockets[lv.FB]; ok {
+				var out interface{}
 
-				ctx = con.ctx(d.ns, d.db)
+				// Create a new context for this socket
+				// which has the correct connection
+				// variables, and auth levels.
+
+				ctx = sck.(*socket).ctx(d.ns, d.db)
 
 				// Check whether the change was made by
 				// the same connection as the live query,
@@ -111,14 +113,14 @@ func (d *document) lives(ctx context.Context, when method) (err error) {
 
 				switch when {
 				case _DELETE:
-					con.queue(id, lv.ID, "DELETE", d.id)
+					sck.(*socket).queue(id, lv.ID, "DELETE", d.id)
 				case _CREATE:
 					if out != nil {
-						con.queue(id, lv.ID, "CREATE", out)
+						sck.(*socket).queue(id, lv.ID, "CREATE", out)
 					}
 				case _UPDATE:
 					if out != nil {
-						con.queue(id, lv.ID, "UPDATE", out)
+						sck.(*socket).queue(id, lv.ID, "UPDATE", out)
 					}
 				}
 

db/socket.go

@@ -37,15 +37,21 @@ type socket struct {
 }
 
 func clear(id string) {
-	for _, s := range sockets {
-		s.clear(id)
-	}
+	go func() {
+		sockets.Range(func(key, val interface{}) bool {
+			val.(*socket).clear(id)
+			return true
+		})
+	}()
 }
 
 func flush(id string) {
-	for _, s := range sockets {
-		s.flush(id)
-	}
+	go func() {
+		sockets.Range(func(key, val interface{}) bool {
+			val.(*socket).flush(id)
+			return true
+		})
+	}()
 }
 
 func (s *socket) ctx(ns, db string) (ctx context.Context) {
@@ -119,22 +125,11 @@ func (s *socket) flush(id string) (err error) {
 		Params: s.items[id],
 	}
 
-	// Check the websocket subprotocol
-	// and send the relevant message
-	// type containing the notification.
+	// Notify the websocket connection
+	// y sending an RPCNotification type
+	// to the notify channel.
 
-	sock := s.fibre.Socket()
-
-	switch sock.Subprotocol() {
-	default:
-		err = sock.SendJSON(obj)
-	case "json":
-		err = sock.SendJSON(obj)
-	case "cbor":
-		err = sock.SendCBOR(obj)
-	case "pack":
-		err = sock.SendPACK(obj)
-	}
+	s.fibre.Socket().Notify(obj)
 
 	// Make sure that we clear all the
 	// pending message notifications
@@ -225,7 +220,7 @@ func (s *socket) check(e *executor, ctx context.Context, ns, db, tb string) (err
 
 func (s *socket) deregister(id string) {
 
-	delete(sockets, id)
+	sockets.Delete(id)
 
 	txn, _ := db.Begin(context.Background(), true)
 

glide.lock

@@ -1,12 +1,12 @@
 hash: c56e5bd935dd1933a6e7370fe3fc67ea26169ec91aa05c171543866c6c2490ed
-updated: 2018-04-24T13:32:49.661918+01:00
+updated: 2018-04-24T23:43:27.310737+01:00
 imports:
 - name: github.com/abcum/bump
   version: 526934c541e071b5a330671c76434b9e32d55638
 - name: github.com/abcum/cork
   version: c246208017d0b81f2e9a3fc2fb7a993c89153839
 - name: github.com/abcum/fibre
-  version: 1b1947da964c0c0a244868279f9476df093eef34
+  version: 24b2157453a929f7a86616c415d01b94916b3ed5
   subpackages:
   - mw
 - name: github.com/abcum/ptree