dd-test-weights

Duration weights for dd-trace-rb unit test batch scheduling. Kept out of the tracer repo so the generated data does not pollute its diffs, and so the refresh can run on a schedule instead of relying on a manual commit.

Data flow

dd-trace-rb Unit Tests run          this repo                     dd-trace-rb
  uploads timings-*     cron job downloads artifacts,  matrix generation
  artifacts on master    aggregates medians, commits     fetches ci_task_timings.json
                         ci_task_timings.json            from raw.githubusercontent.com

Refresh process

Automated by .github/workflows/update-weights.yml (daily cron, or manual via workflow_dispatch). The job:

1. Lists recent successful Unit Tests runs on DataDog/dd-trace-rb@master.
2. Downloads their timings-* artifacts (requires PAT_TOKEN secret, see below).
3. Runs dd-trace-rb's own github:update_task_timings rake task from a checkout of DataDog/dd-trace-rb (no code is duplicated here).
4. Commits the new ci_task_timings.json if it changed.

New test tasks run on fallback estimates in dd-trace-rb until the next refresh records real durations. Deleted tasks leave stale entries; they are looked up by key, so they are harmless bloat.

Secrets

PAT_TOKEN: a GitHub token that can read workflow artifacts from the public DataDog/dd-trace-rb repository (a classic PAT with repo scope works; the repo is public so no write access is needed).

Consumer contract

dd-trace-rb fetches ci_task_timings.json from this repo's default branch at matrix-generation time. Consumers must tolerate a fetch failure and fall back to their own estimate defaults; CI must not break if this repo is unavailable or stale.

Upgrade path

This file-based store is a stand-in for a service. When Datadog CI Visibility or Test Optimization ships a distribution API, replace the fetch URL on the consumer side and retire this repo. The interface is deliberately one GET request.

Ownership

Owner: tony.hsu. If the cron job stops running, weights silently go stale; check the latest commit date on ci_task_timings.json before debugging batch balance.