Do not fetch accounts on system events.

Noticed we would lookup accounts, but would also fetch them when tracking remote connections, etc.

Signed-off-by: Derek Collison <derek@nats.io>

server/events.go

@@ -678,10 +678,16 @@ func (s *Server) connsRequest(sub *subscription, _ *client, subject, reply strin
 		s.sys.client.Errorf("Error unmarshalling account connections request message: %v", err)
 		return
 	}
-	acc, _ := s.lookupAccount(m.Account)
+	// Here we really only want to lookup the account if its local. We do not want to fetch this
+	// account if we have no interest in it.
+	var acc *Account
+	if v, ok := s.accounts.Load(m.Account); ok {
+		acc = v.(*Account)
+	}
 	if acc == nil {
 		return
 	}
+	// We know this is a local connection.
 	if nlc := acc.NumLocalConnections(); nlc > 0 {
 		s.mu.Lock()
 		s.sendAccConnsUpdate(acc, reply)
@@ -733,7 +739,15 @@ func (s *Server) remoteConnsUpdate(sub *subscription, _ *client, subject, reply
 	}
 
 	// See if we have the account registered, if not drop it.
-	acc, _ := s.lookupAccount(m.Account)
+	// Make sure this does not force us to load this account here.
+	var acc *Account
+	if v, ok := s.accounts.Load(m.Account); ok {
+		acc = v.(*Account)
+	}
+	// Silently ignore these if we do not have local interest in the account.
+	if acc == nil {
+		return
+	}
 
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -742,23 +756,17 @@ func (s *Server) remoteConnsUpdate(sub *subscription, _ *client, subject, reply
 	if !s.running || !s.eventsEnabled() {
 		return
 	}
-
 	// Double check that this is not us, should never happen, so error if it does.
 	if m.Server.ID == s.info.ID {
 		s.sys.client.Errorf("Processing our own account connection event message: ignored")
 		return
 	}
-	if acc == nil {
-		s.sys.client.Debugf("Received account connection event for unknown account: %s", m.Account)
-		return
-	}
 	// If we are here we have interest in tracking this account. Update our accounting.
 	acc.updateRemoteServer(&m)
 	s.updateRemoteServer(&m.Server)
 }
 
-// Setup tracking for this account. This allows us to track globally
-// account activity.
+// Setup tracking for this account. This allows us to track global account activity.
 // Lock should be held on entry.
 func (s *Server) enableAccountTracking(a *Account) {
 	if a == nil || !s.eventsEnabled() {

server/server.go

@@ -699,6 +699,11 @@ func (s *Server) numAccounts() int {
 	return count
 }
 
+// NumLoadedAccounts returns the number of loaded accounts.
+func (s *Server) NumLoadedAccounts() int {
+	return s.numAccounts()
+}
+
 // LookupOrRegisterAccount will return the given account if known or create a new entry.
 func (s *Server) LookupOrRegisterAccount(name string) (account *Account, isNew bool) {
 	if v, ok := s.accounts.Load(name); ok {

test/operator_test.go

@@ -427,7 +427,7 @@ func TestReloadDoesNotWipeAccountsWithOperatorMode(t *testing.T) {
 	checkForMsg()
 }
 
-func TestReloadDoesUpdatesAccountsWithMemoryResolver(t *testing.T) {
+func TestReloadDoesUpdateAccountsWithMemoryResolver(t *testing.T) {
 	// We will run an operator mode server with a memory resolver.
 	// Reloading should behave similar to configured accounts.
 
@@ -578,3 +578,84 @@ func TestReloadFailsWithBadAccountsWithMemoryResolver(t *testing.T) {
 		t.Fatalf("Got unexpected error on reload: %v", err)
 	}
 }
+
+func TestConnsRequestDoesNotLoadAccountCheckingConnLimits(t *testing.T) {
+	// Create two accounts, system and normal account.
+	sysJWT, sysKP := createAccountForConfig(t)
+	sysPub, _ := sysKP.PublicKey()
+
+	// Do this account by nad to add in connection limits
+	okp, _ := nkeys.FromSeed(oSeed)
+	accKP, _ := nkeys.CreateAccount()
+	accPub, _ := accKP.PublicKey()
+	nac := jwt.NewAccountClaims(accPub)
+	nac.Limits.Conn = 10
+	accJWT, _ := nac.Encode(okp)
+
+	cf := `
+	listen: 127.0.0.1:-1
+	cluster {
+		listen: 127.0.0.1:-1
+		authorization {
+			timeout: 2.2
+		} %s
+	}
+
+	operator = "./configs/nkeys/op.jwt"
+	system_account = "%s"
+
+	resolver = MEMORY
+	resolver_preload = {
+		%s : "%s"
+		%s : "%s"
+	}
+	`
+	contents := strings.Replace(fmt.Sprintf(cf, "", sysPub, sysPub, sysJWT, accPub, accJWT), "\n\t", "\n", -1)
+	conf := createConfFile(t, []byte(contents))
+	defer os.Remove(conf)
+
+	s, opts := RunServerWithConfig(conf)
+	defer s.Shutdown()
+
+	// Create a new server and route to main one.
+	routeStr := fmt.Sprintf("\n\t\troutes = [nats-route://%s:%d]", opts.Cluster.Host, opts.Cluster.Port)
+	contents2 := strings.Replace(fmt.Sprintf(cf, routeStr, sysPub, sysPub, sysJWT, accPub, accJWT), "\n\t", "\n", -1)
+
+	conf2 := createConfFile(t, []byte(contents2))
+	defer os.Remove(conf2)
+
+	s2, _ := RunServerWithConfig(conf2)
+	defer s2.Shutdown()
+
+	checkClusterFormed(t, s, s2)
+
+	// Make sure that we do not have the account loaded.
+	// Just SYS and $G
+	if nla := s.NumLoadedAccounts(); nla != 2 {
+		t.Fatalf("Expected only 2 loaded accounts, got %d", nla)
+	}
+	if nla := s2.NumLoadedAccounts(); nla != 2 {
+		t.Fatalf("Expected only 2 loaded accounts, got %d", nla)
+	}
+
+	// Now connect to first server on accPub.
+	nc, err := nats.Connect(s.ClientURL(), createUserCreds(t, s, accKP))
+	if err != nil {
+		t.Fatalf("Error on connect: %v", err)
+	}
+	defer nc.Close()
+
+	// Just wait for the request for connections to move to S2 and cause a fetch.
+	// This is what we want to fix.
+	time.Sleep(100 * time.Millisecond)
+
+	// We should have 3 here for sure.
+	if nla := s.NumLoadedAccounts(); nla != 3 {
+		t.Fatalf("Expected 3 loaded accounts, got %d", nla)
+	}
+
+	// Now make sure that we still only have 2 loaded accounts on server 2.
+	if nla := s2.NumLoadedAccounts(); nla != 2 {
+		t.Fatalf("Expected only 2 loaded accounts, got %d", nla)
+	}
+}