What causes "nest: failed to generate rtsp url" in AlexxIT/go2rtc?

Confirm the specific camera model supports RTSP streaming via the SDM API (many battery/doorbell devices do not).

nest: failed to generate rtsp url

Error message

nest: failed to generate rtsp url

What it means

GenerateRtspStream (pkg/nest/api.go:375) got a 200 response but the decoded results contain no "rtspUrl" key in the streamUrls map. The library treats a missing RTSP URL as a failed stream generation even though the HTTP call succeeded.

Solutions

Confirm the specific camera model supports RTSP streaming via the SDM API (many battery/doorbell devices do not).
Log the full resv.Results payload to see what keys were actually returned and adapt parsing.
Fall back to WebRTC streaming (ExchangeSDP path) if RTSP is unsupported for the device.
Check for Nest API changelog updates that may have renamed or moved the streamUrls.rtspUrl field.

Example fix

// before: assuming rtspUrl always exists
url, err := api.GenerateRtspStream(projectID, deviceID)
// after: validate device support and handle absence
device, _ := sdm.GetDevice(deviceID)
if !device.SupportsRtsp() { return useWebRtc(device) }
url, err := api.GenerateRtspStream(projectID, deviceID)

Defensive patterns

Strategy: fallback

Validate before calling

device, err := sdmClient.GetDevice(ctx, deviceID)
if err != nil { return err }
if !device.Traits["sdm.devices.traits.CameraLiveStream"].SupportsRtsp { return useWebRtcFallback(deviceID) }

Type guard

func hasRtspUrl(results struct{ StreamURLs map[string]string }) bool {
    u, ok := results.StreamURLs["rtspUrl"]
    return ok && u != ""
}

Try / catch

url, err := api.GenerateRtspStream(projectID, deviceID)
if err != nil && strings.Contains(err.Error(), "failed to generate rtsp url") {
    return startWebRtcStream(deviceID) // device likely lacks RTSP
}
if err != nil { return err }

Prevention

Check the device's CameraLiveStream trait/supportedProtocols before choosing RTSP.
Log the full generate response body when this error occurs to capture the actual shape.
Implement a WebRTC (ExchangeSDP) fallback path for non-RTSP cameras.
Watch the Nest SDM API changelog for streamUrls field changes.

When it happens

Trigger: Nest returns 200 with a streamUrls map that lacks the "rtspUrl" entry — e.g. the camera does not support RTSP, the SDM response shape changed, or the command silently failed with an empty results payload.

Common situations: Doorbell or battery cameras that don't expose RTSP; Nest API contract/field changes; devices streaming via WebRTC only; partially successful command responses with empty streamUrls.

Related errors

AI-assisted analysis of AlexxIT/go2rtc@c245815e75 (2026-09-07). Data as JSON: /api/errors/5a27c74948a91e03. Report an issue: GitHub.

Appendix: source

Thrown at pkg/nest/api.go:375

	if res.StatusCode != 200 {
		return "", errors.New("nest: wrong status: " + res.Status)
	}

	var resv struct {
		Results struct {
			StreamURLs           map[string]string `json:"streamUrls"`
			StreamExtensionToken string            `json:"streamExtensionToken"`
			StreamToken          string            `json:"streamToken"`
			ExpiresAt            time.Time         `json:"expiresAt"`
		} `json:"results"`
	}

	if err = json.NewDecoder(res.Body).Decode(&resv); err != nil {
		return "", err
	}

	if _, ok := resv.Results.StreamURLs["rtspUrl"]; !ok {
		return "", errors.New("nest: failed to generate rtsp url")
	}

	a.StreamProjectID = projectID
	a.StreamDeviceID = deviceID
	a.StreamToken = resv.Results.StreamToken
	a.StreamExtensionToken = resv.Results.StreamExtensionToken
	a.StreamExpiresAt = resv.Results.ExpiresAt

	return resv.Results.StreamURLs["rtspUrl"], nil
}

func (a *API) StopRTSPStream() error {
	if a.StreamProjectID == "" || a.StreamDeviceID == "" {
		return errors.New("nest: tried to stop rtsp stream without a project or device ID")
	}

	var reqv struct {
		Command string `json:"command"`

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