Debug Shared Storage

Tools to debug issues with Shared Storage.

Debug Shared Storage worklets with DevTools

To inspect the Shared Storage worklets started from the page you are on, you can visit the "Sources" tab in the DevTools panel, and add the "Shared Storage Worklet / Script First Statement" event listener breakpoint. This breakpoint will pause the initial module script execution or short-lived worklets on startup.

Debugging a Shared Storage worklet by adding event-level listener.
A breakpoint can be added to a Shared Storage worklet.

Additionally, the chrome://inspect/#shared-storage-worklets page shows all active Shared Storage worklets from all pages.

Shared Storage and Private Aggregation Debugging

To enable debugging, call the enableDebugMode() JavaScript method in the same context where Shared Storage and Private Aggregation is used. This will be applied for future reports in the same context.

privateAggregation.enableDebugMode();

To associate the reports with the contexts that triggered them, you can set a 64-bit unsigned integer debug key which is passed to the JavaScript call. The debugKey is a BigInt.

privateAggregation.enableDebugMode({debugKey: 1234});

Debug Shared Storage

Shared Storage returns a generic error message:

Promise is rejected without and explicit error message

You can debug Shared Storage by wrapping the calls with try-catch blocks.

try {
  privateAggregation.contributeToHistogram({bucket, value});
} catch (e){
  console.log(e);
}

Debug Private Aggregation

Reports are sent to /.well-known/private-aggregation/report-shared-storage and /.well-known/private-aggregation/debug/report-shared-storage. Debug reports receive a payload similar to the following JSON. This payload defines the api field as "shared-storage".

{
   "aggregation_coordinator_origin": "https://publickeyservice.msmt.gcp.privacysandboxservices.com",
   "aggregation_service_payloads": [ {
      "debug_cleartext_payload": "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",
      "key_id": "1569ab37-da44-4a26-80d9-5ed6524ab2a7",
      "payload": "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"
   } ],
   "debug_key": "1234",
   "shared_info": "{\"api\":\"shared-storage\",\"debug_mode\":\"enabled\",\"report_id\":\"80d93c0a-a94e-4ab7-aeb5-a4ecd4bfc598\",\"reporting_origin\":\"https://privacy-sandbox-demos-dsp.dev\",\"scheduled_report_time\":\"1717784740\",\"version\":\"0.1\"}"
}

Debug cleartext payload

The debug_cleartext_payload is Base64 CBOR-encoded. You can view the bucket and value using the decoder or use the JavaScript code found in the Shared Storage decoder.

Engage and share feedback

Note that the Shared Storage API proposal is under active discussion and development and therefore subject to change.

We're eager to hear your thoughts on the Shared Storage API.

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