owasp-amass/amass · critical

failed to create the session manager

Error message

failed to create the session manager

What it means

NewEngine constructs the core engine; sessions.NewManager returning nil means the session manager could not be instantiated, so the engine cannot manage enumeration sessions and NewEngine aborts with this error.

Source

Thrown at engine/engine.go:44

	Dispatcher et.Dispatcher
	Registry   et.Registry
	Manager    et.SessionManager
	Server     *server.Server
}

func NewEngine(l *slog.Logger) (*Engine, error) {
	go func() {
		_ = http.ListenAndServe("127.0.0.1:6060", nil)
	}()

	if l == nil {
		l = slog.New(slog.NewTextHandler(os.Stdout, nil))
	}

	reg := registry.NewRegistry(l)
	mgr := sessions.NewManager(l, reg)
	if mgr == nil {
		return nil, errors.New("failed to create the session manager")
	}

	dis := dispatcher.NewDispatcher(l, reg, mgr)
	if err := plugins.LoadAndStartPlugins(reg); err != nil {
		return nil, err
	}

	srv, err := server.NewServer(l, dis, mgr)
	if err != nil || srv == nil {
		dis.Shutdown()
		mgr.Shutdown()
		return nil, errors.New("failed to create the API server")
	}

	ch := make(chan error, 1)
	go func(errch chan error) { errch <- srv.Start() }(ch)

	t := time.NewTimer(3 * time.Second)

View on GitHub (pinned to 79299dce87)

Solutions

1. Rebuild/reinstall the engine to ensure the sessions package is intact
2. Check that registry.NewRegistry returned a valid registry before creating the manager
3. Inspect sessions.NewManager for conditions that return nil and fix the underlying cause
4. Report upstream if NewManager nil-returns with valid inputs

eng, err := NewEngine(cfg)
if err != nil {
    log.Fatalf("engine initialization failed: %v", err)
}

When it happens

Trigger: Calling NewEngine (via CLIWorkflow) when sessions.NewManager returns nil — an internal construction failure of the session manager (e.g. nil registry/logger downstream).

Common situations: Inconsistent or broken build where the sessions package fails its internal checks; corrupted installation; a code change altering NewManager's contract without updating this check.

Related errors

• failed to create the API server
• failed to create the RDAP disk cache
• failed to initialize database store:
• config seed and scope are not initialized

AI-assisted analysis of owasp-amass/amass@79299dce87 (2026-09-06). Data as JSON: /api/errors/10b6e5004d111bd0. Report an issue: GitHub.