grafana/k6 · error

updating offline mode for frame

Error message

updating offline mode for frame %v: %w

What it means

Wrap of a NetworkManager.SetOfflineMode failure for a specific frame target: updateOffline reads the browser context's Offline option and, when it is set (or on non-initial updates), toggles the CDP Network.emulateNetworkConditions state. The error fires when the emulate-network command is rejected — most commonly because the frame's session was already detached during navigation or the browser target crashed. The %v is the frame's target ID.

Solutions

  1. Confirm the frame still exists and its CDP session is attached before toggling offline mode
  2. Apply the offline option at browser-context creation instead of changing it mid-navigation
  3. Retry the operation after the page finishes navigating
  4. Check browser logs if every emulateNetworkConditions call fails, indicating a protocol/version mismatch
Defensive patterns

Strategy: retry

When it happens

Trigger: Thrown at internal/js/modules/k6/browser/common/frame_session.go:1193 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of grafana/k6@3fcf5388d7 (2026-08-18). Data as JSON: /api/errors/753dc3d384f6aa6f. Report an issue: GitHub.

Appendix: source

Thrown at internal/js/modules/k6/browser/common/frame_session.go:1251

func (fs *FrameSession) updateHTTPCredentials(initial bool) error {
	fs.logger.Debugf("NewFrameSession:updateHttpCredentials", "sid:%v tid:%v", fs.session.ID(), fs.targetID)

	credentials := fs.page.browserCtx.opts.HTTPCredentials
	if !initial || !credentials.IsEmpty() {
		return fs.networkManager.Authenticate(credentials)
	}

	return nil
}

func (fs *FrameSession) updateOffline(initial bool) error {
	fs.logger.Debugf("NewFrameSession:updateOffline", "sid:%v tid:%v", fs.session.ID(), fs.targetID)

	offline := fs.page.browserCtx.opts.Offline
	if !initial || offline {
		if err := fs.networkManager.SetOfflineMode(offline); err != nil {
			return fmt.Errorf("updating offline mode for frame %v: %w", fs.targetID, err)
		}
	}

	return nil
}

func (fs *FrameSession) throttleNetwork(networkProfile NetworkProfile) error {
	fs.logger.Debugf("NewFrameSession:throttleNetwork", "sid:%v tid:%v", fs.session.ID(), fs.targetID)

	return fs.networkManager.ThrottleNetwork(networkProfile)
}

func (fs *FrameSession) throttleCPU(cpuProfile CPUProfile) error {
	action := emulation.SetCPUThrottlingRate(cpuProfile.Rate)
	if err := action.Do(cdp.WithExecutor(fs.ctx, fs.session)); err != nil {
		return fmt.Errorf("throttling CPU: %w", err)
	}

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