package management import ( "context" "fmt" "net" "net/http" "os" "sync" "time" "github.com/go-chi/chi/v5" "github.com/go-chi/cors" "github.com/google/uuid" "github.com/prometheus/client_golang/prometheus/promhttp" "github.com/rs/zerolog" "nhooyr.io/websocket" ) const ( // In the current state, an invalid command was provided by the client StatusInvalidCommand websocket.StatusCode = 4001 reasonInvalidCommand = "expected start streaming as first event" // There are a limited number of available streaming log sessions that cloudflared will service, exceeding this // value will return this error to incoming requests. StatusSessionLimitExceeded websocket.StatusCode = 4002 reasonSessionLimitExceeded = "limit exceeded for streaming sessions" // There is a limited idle time while not actively serving a session for a request before dropping the connection. StatusIdleLimitExceeded websocket.StatusCode = 4003 reasonIdleLimitExceeded = "session was idle for too long" ) type ManagementService struct { // The management tunnel hostname Hostname string // Host details related configurations serviceIP string clientID uuid.UUID label string // Additional Handlers metricsHandler http.Handler log *zerolog.Logger router chi.Router // streamingMut is a lock to prevent concurrent requests to start streaming. Utilizing the atomic.Bool is not // sufficient to complete this operation since many other checks during an incoming new request are needed // to validate this before setting streaming to true. streamingMut sync.Mutex logger LoggerListener } func New(managementHostname string, serviceIP string, clientID uuid.UUID, label string, log *zerolog.Logger, logger LoggerListener, ) *ManagementService { s := &ManagementService{ Hostname: managementHostname, log: log, logger: logger, serviceIP: serviceIP, clientID: clientID, label: label, metricsHandler: promhttp.Handler(), } r := chi.NewRouter() r.Use(ValidateAccessTokenQueryMiddleware) r.Get("/ping", ping) r.Head("/ping", ping) r.Get("/logs", s.logs) r.Get("/metrics", s.metricsHandler.ServeHTTP) r.Route("/host_details", func(r chi.Router) { // CORS middleware required to allow dash to access management.argotunnel.com requests r.Use(cors.Handler(cors.Options{ // Allows for any subdomain of cloudflare.com AllowedOrigins: []string{"https://*.cloudflare.com"}, // Required to present cookies or other authentication across origin boundries AllowCredentials: true, MaxAge: 300, // Maximum value not ignored by any of major browsers })) r.Get("/", s.getHostDetails) }) s.router = r return s } func (m *ManagementService) ServeHTTP(w http.ResponseWriter, r *http.Request) { m.router.ServeHTTP(w, r) } // Management Ping handler func ping(w http.ResponseWriter, r *http.Request) { w.WriteHeader(200) } // The response provided by the /host_details endpoint type getHostDetailsResponse struct { ClientID string `json:"connector_id"` IP string `json:"ip,omitempty"` HostName string `json:"hostname,omitempty"` } func (m *ManagementService) getHostDetails(w http.ResponseWriter, r *http.Request) { var getHostDetailsResponse = getHostDetailsResponse{ ClientID: m.clientID.String(), } if ip, err := getPrivateIP(m.serviceIP); err == nil { getHostDetailsResponse.IP = ip } getHostDetailsResponse.HostName = m.getLabel() w.Header().Set("Content-Type", "application/json") w.WriteHeader(200) json.NewEncoder(w).Encode(getHostDetailsResponse) } func (m *ManagementService) getLabel() string { if m.label != "" { return fmt.Sprintf("custom:%s", m.label) } // If no label is provided we return the system hostname. This is not // a fqdn hostname. hostname, err := os.Hostname() if err != nil { return "unknown" } return hostname } // Get preferred private ip of this machine func getPrivateIP(addr string) (string, error) { conn, err := net.DialTimeout("tcp", addr, 1*time.Second) if err != nil { return "", err } defer conn.Close() localAddr := conn.LocalAddr().String() host, _, err := net.SplitHostPort(localAddr) return host, err } // readEvents will loop through all incoming websocket messages from a client and marshal them into the // proper Event structure and pass through to the events channel. Any invalid messages sent will automatically // terminate the connection. func (m *ManagementService) readEvents(c *websocket.Conn, ctx context.Context, events chan<- *ClientEvent) { for { event, err := ReadClientEvent(c, ctx) select { case <-ctx.Done(): return default: if err != nil { // If the client (or the server) already closed the connection, don't attempt to close it again if !IsClosed(err, m.log) { m.log.Err(err).Send() m.log.Err(c.Close(websocket.StatusUnsupportedData, err.Error())).Send() } // Any errors when reading the messages from the client will close the connection return } events <- event } } } // streamLogs will begin the process of reading from the Session listener and write the log events to the client. func (m *ManagementService) streamLogs(c *websocket.Conn, ctx context.Context, session *session) { for session.Active() { select { case <-ctx.Done(): session.Stop() return case event := <-session.listener: err := WriteEvent(c, ctx, &EventLog{ ServerEvent: ServerEvent{Type: Logs}, Logs: []*Log{event}, }) if err != nil { // If the client (or the server) already closed the connection, don't attempt to close it again if !IsClosed(err, m.log) { m.log.Err(err).Send() m.log.Err(c.Close(websocket.StatusInternalError, err.Error())).Send() } // Any errors when writing the messages to the client will stop streaming and close the connection session.Stop() return } default: // No messages to send } } } // canStartStream will check the conditions of the request and return if the session can begin streaming. func (m *ManagementService) canStartStream(session *session) bool { m.streamingMut.Lock() defer m.streamingMut.Unlock() // Limits to one actor for streaming logs if m.logger.ActiveSessions() > 0 { // Allow the same user to preempt their existing session to disconnect their old session and start streaming // with this new session instead. if existingSession := m.logger.ActiveSession(session.actor); existingSession != nil { m.log.Info(). Msgf("Another management session request for the same actor was requested; the other session will be disconnected to handle the new request.") existingSession.Stop() m.logger.Remove(existingSession) existingSession.cancel() } else { m.log.Warn(). Msgf("Another management session request was attempted but one session already being served; there is a limit of streaming log sessions to reduce overall performance impact.") return false } } return true } // parseFilters will check the ClientEvent for start_streaming and assign filters if provided to the session func (m *ManagementService) parseFilters(c *websocket.Conn, event *ClientEvent, session *session) bool { // Expect the first incoming request startEvent, ok := IntoClientEvent[EventStartStreaming](event, StartStreaming) if !ok { return false } session.Filters(startEvent.Filters) return true } // Management Streaming Logs accept handler func (m *ManagementService) logs(w http.ResponseWriter, r *http.Request) { c, err := websocket.Accept(w, r, &websocket.AcceptOptions{ OriginPatterns: []string{ "*.cloudflare.com", }, }) if err != nil { m.log.Debug().Msgf("management handshake: %s", err.Error()) return } // Make sure the connection is closed if other go routines fail to close the connection after completing. defer c.Close(websocket.StatusInternalError, "") ctx, cancel := context.WithCancel(r.Context()) defer cancel() events := make(chan *ClientEvent) go m.readEvents(c, ctx, events) // Send a heartbeat ping to hold the connection open even if not streaming. ping := time.NewTicker(15 * time.Second) defer ping.Stop() // Close the connection if no operation has occurred after the idle timeout. The timeout is halted // when streaming logs is active. idleTimeout := 5 * time.Minute idle := time.NewTimer(idleTimeout) defer idle.Stop() // Fetch the claims from the request context to acquire the actor claims, ok := ctx.Value(accessClaimsCtxKey).(*managementTokenClaims) if !ok || claims == nil { // Typically should never happen as it is provided in the context from the middleware m.log.Err(c.Close(websocket.StatusInternalError, "missing access_token")).Send() return } session := newSession(logWindow, claims.Actor, cancel) defer m.logger.Remove(session) for { select { case <-ctx.Done(): m.log.Debug().Msgf("management logs: context cancelled") c.Close(websocket.StatusNormalClosure, "context closed") return case event := <-events: switch event.Type { case StartStreaming: idle.Stop() // Expect the first incoming request startEvent, ok := IntoClientEvent[EventStartStreaming](event, StartStreaming) if !ok { m.log.Warn().Msgf("expected start_streaming as first recieved event") m.log.Err(c.Close(StatusInvalidCommand, reasonInvalidCommand)).Send() return } // Make sure the session can start if !m.canStartStream(session) { m.log.Err(c.Close(StatusSessionLimitExceeded, reasonSessionLimitExceeded)).Send() return } session.Filters(startEvent.Filters) m.logger.Listen(session) m.log.Debug().Msgf("Streaming logs") go m.streamLogs(c, ctx, session) continue case StopStreaming: idle.Reset(idleTimeout) // Stop the current session for the current actor who requested it session.Stop() m.logger.Remove(session) case UnknownClientEventType: fallthrough default: // Drop unknown events and close connection m.log.Debug().Msgf("unexpected management message received: %s", event.Type) // If the client (or the server) already closed the connection, don't attempt to close it again if !IsClosed(err, m.log) { m.log.Err(err).Err(c.Close(websocket.StatusUnsupportedData, err.Error())).Send() } return } case <-ping.C: go c.Ping(ctx) case <-idle.C: c.Close(StatusIdleLimitExceeded, reasonIdleLimitExceeded) return } } }