status: return error if subserver already registered

Let the status manager first check its map of subservers before
registering a new one to ensure that an existing subserver is not being
overridden.

Author: ellemouton

status/manager.go

@@ -145,30 +145,38 @@ func (s *Manager) SubServerStatus(_ context.Context,
 
 // RegisterSubServer will create a new sub-server entry for the Manager to
 // keep track of.
-func (s *Manager) RegisterSubServer(name string, opts ...SubServerOption) {
+func (s *Manager) RegisterSubServer(name string,
+	opts ...SubServerOption) error {
+
 	s.mu.RLock()
 	defer s.mu.RUnlock()
 
-	s.registerSubServerUnsafe(name, true, opts...)
+	return s.registerSubServerUnsafe(name, true, opts...)
 }
 
 // RegisterAndEnableSubServer will create a new sub-server entry for the
 // Manager to keep track of and will set it as enabled.
 func (s *Manager) RegisterAndEnableSubServer(name string,
-	opts ...SubServerOption) {
+	opts ...SubServerOption) error {
 
 	s.mu.RLock()
 	defer s.mu.RUnlock()
 
-	s.registerSubServerUnsafe(name, false, opts...)
+	return s.registerSubServerUnsafe(name, false, opts...)
 }
 
 func (s *Manager) registerSubServerUnsafe(name string, disabled bool,
-	opts ...SubServerOption) {
+	opts ...SubServerOption) error {
+
+	_, ok := s.subServers[name]
+	if ok {
+		return fmt.Errorf("a subserver with name %s has already "+
+			"been registered with the status manager", name)
+	}
 
-	ss := newSubServer(disabled, opts...)
+	s.subServers[name] = newSubServer(disabled, opts...)
 
-	s.subServers[name] = ss
+	return nil
 }
 
 // SetCustomStatus updates the custom status of the given sub-server to the

subservers/manager.go

@@ -53,7 +53,10 @@ func NewManager(permsMgr *perms.Manager,
 // AddServer adds a new subServer to the manager's set.
 func (s *Manager) AddServer(ss SubServer, enable bool) error {
 	// Register all sub-servers with the status server.
-	s.statusServer.RegisterSubServer(ss.Name())
+	err := s.statusServer.RegisterSubServer(ss.Name())
+	if err != nil {
+		return err
+	}
 
 	// If the sub-server has explicitly been disabled, then we don't add it
 	// to the set of servers tracked by the Manager.

terminal.go

@@ -279,11 +279,22 @@ func (g *LightningTerminal) Run() error {
 	}
 
 	// Register LND, LiT and Accounts with the status manager.
-	g.statusMgr.RegisterAndEnableSubServer(
+	err = g.statusMgr.RegisterAndEnableSubServer(
 		subservers.LND, status.WithIsReadyOverride(lndOverride),
 	)
-	g.statusMgr.RegisterAndEnableSubServer(subservers.LIT)
-	g.statusMgr.RegisterSubServer(subservers.ACCOUNTS)
+	if err != nil {
+		return err
+	}
+
+	err = g.statusMgr.RegisterAndEnableSubServer(subservers.LIT)
+	if err != nil {
+		return err
+	}
+
+	err = g.statusMgr.RegisterSubServer(subservers.ACCOUNTS)
+	if err != nil {
+		return err
+	}
 
 	// Also enable the accounts subserver if it's not disabled.
 	if !g.cfg.Accounts.Disable {