Do all session pruning in a single goroutine

server/auth.go

@@ -35,6 +35,8 @@ func (d *Dispatch) handleAuth(w http.ResponseWriter, r *http.Request, createUser
 					d.states.deleteSession(key)
 					session.SetCookie(w, r)
 				}
+			} else {
+				d.states.deleteSession(key)
 			}
 		}
 
@@ -76,7 +78,6 @@ func (d *Dispatch) newUser(w http.ResponseWriter, r *http.Request) (*State, erro
 		return nil, err
 	}
 	d.states.setSession(session)
-	go d.deleteSessionWhenExpired(session)
 
 	state := NewState(user, d)
 	d.states.set(state)
@@ -86,12 +87,3 @@ func (d *Dispatch) newUser(w http.ResponseWriter, r *http.Request) (*State, erro
 
 	return state, nil
 }
-
-func (d *Dispatch) deleteSessionWhenExpired(session *session.Session) {
-	deleteSessionWhenExpired(session, d.states)
-}
-
-func deleteSessionWhenExpired(session *session.Session, stateStore *stateStore) {
-	session.WaitUntilExpiration()
-	stateStore.deleteSession(session.Key())
-}

server/server.go

@@ -45,6 +45,7 @@ func (d *Dispatch) Run() {
 	session.CookieName = "dispatch"
 
 	d.states = newStateStore(d.SessionStore)
+	go d.states.run()
 
 	d.loadUsers()
 	d.initFileServer()
@@ -57,7 +58,7 @@ func (d *Dispatch) loadUsers() {
 		log.Fatal(err)
 	}
 
-	log.Printf("Loading %d user(s)", len(users))
+	log.Printf("[Init] %d users", len(users))
 
 	for _, user := range users {
 		go d.loadUser(user)

server/state.go

@@ -244,11 +244,12 @@ func newStateStore(sessionStore storage.SessionStore) *stateStore {
 		log.Fatal(err)
 	}
 
+	log.Printf("[Init] %d sessions", len(sessions))
+
 	for _, session := range sessions {
 		if !session.Expired() {
 			session.Init()
 			store.sessions[session.Key()] = session
-			go deleteSessionWhenExpired(session, store)
 		} else {
 			go sessionStore.DeleteSession(session.Key())
 		}
@@ -257,6 +258,22 @@ func newStateStore(sessionStore storage.SessionStore) *stateStore {
 	return store
 }
 
+func (s *stateStore) run() {
+	pruneSessions := time.Tick(time.Minute * 5)
+	for {
+		select {
+		case <-pruneSessions:
+			s.lock.Lock()
+			for key, session := range s.sessions {
+				if session.Expired() {
+					s.internalDeleteSession(key)
+				}
+			}
+			s.lock.Unlock()
+		}
+	}
+}
+
 func (s *stateStore) get(id uint64) *State {
 	s.lock.Lock()
 	state := s.states[id]
@@ -298,26 +315,34 @@ func (s *stateStore) setSession(session *session.Session) {
 
 func (s *stateStore) deleteSession(key string) {
 	s.lock.Lock()
+	s.internalDeleteSession(key)
+	s.lock.Unlock()
+}
+
+func (s *stateStore) internalDeleteSession(key string) {
 	id := s.sessions[key].UserID
 	delete(s.sessions, key)
+
 	n := 0
 	for _, session := range s.sessions {
 		if session.UserID == id {
 			n++
 		}
 	}
+
 	state := s.states[id]
 	if n == 0 {
 		delete(s.states, id)
 	}
-	s.lock.Unlock()
 
-	if n == 0 {
-		// This anonymous user is not reachable anymore since all sessions have
-		// expired, so we clean it up
-		state.kill()
-		state.user.Remove()
-	}
+	go func() {
+		if n == 0 {
+			// This anonymous user is not reachable anymore since all sessions have
+			// expired, so we clean it up
+			state.kill()
+			state.user.Remove()
+		}
 
-	go s.sessionStore.DeleteSession(key)
+		s.sessionStore.DeleteSession(key)
+	}()
 }