1665331 - Replace Canonical JSON JavaScript implementation with canonical_json Rust crate

Status: NEW

(Firefox :: Remote Settings Client, enhancement)

Description

[Mathieu Leplatre [:leplatrem]]

In order to share the same Canonical JSON serializer implementation between the server and the clients, we can replace the current toolkit/modules/CanonicalJSON.jsm with the canonical_json crate.

See https://bugzilla.mozilla.org/show_bug.cgi?id=1659419
And https://blog.mathieu-leplatre.info/leveraging-rust-in-python-and-javascript.html

Comment 1

[Mathieu Leplatre [:leplatrem]]

I would be interested to know the performance impact of canonical json serialization of huge collections like security-state/intermediates, and see whether it would make sense to replace the current code with our Rust crate.

On my modern machine, it seems reasonable:

>> const { RemoteSettingsWorker } = ChromeUtils.importESModule("resource://services-settings/RemoteSettingsWorker.sys.mjs");
>> const resp = await fetch("https://firefox.settings.services.mozilla.com/v1/buckets/security-state/collections/intermediates/changeset?_expected=00000");
>>  const {changes: records, timestamp} = await resp.json();
  
>> console.time("cjson"); await Promise.all(Array(500000).map(() => RemoteSettingsWorker.canonicalStringify(records, timestamp))); console.timeEnd("cjson");
10:46:29.478 cjson: 687.18ms - timer ended

But how to measure how it would affect browsing and battery on modest devices?