1620186 - Fix race condition during synchronization

Status: RESOLVED FIXED

(Firefox :: Remote Settings Client, enhancement, P3)

Description

[Mathieu Leplatre [:leplatrem]]

For the synchronization of a collection, we fetch data from 2 endpoints (metadata + records) with two different requests. This can lead to race conditions if data is modified in the interval.

Using a single endpoint instead of two, and thus having a single request instead of the current «two steps» synchronization, should prevent race conditions from happening.

On the server side, we could expose a new endpoint (eg. /buckets/{bid}/collections/{cid}/changeset) that would return both metadata and changes in one response.

{
  "data": {
    "changes": [{
        "id": "88687994-5344-11ea-8e6c-472e7b6636b2",
        "last_modified": ...
      },
      …
    ],
    "metadata": {
      …
    }
}

The changes would be filtered using ?_since=<> as usual.
The latest version will always be returned (latest metadata, latest changes since provided timestamp).

Comment 1

[Mathieu Leplatre [:leplatrem]]

Attachment: Bug 1620186 - Upgrade kinto-client to 5.1.1

Comment 2

[Mathieu Leplatre [:leplatrem]]

Attachment: Bug 1620186 - Fetch from changeset endpoint

Depends on D71569

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0f24b88f0cbe
Upgrade kinto-client to 5.1.1 r=glasserc
https://hg.mozilla.org/integration/autoland/rev/20d2e7042fff
Fetch from changeset endpoint r=glasserc

Comment 4

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/0f24b88f0cbe
https://hg.mozilla.org/mozilla-central/rev/20d2e7042fff