fix(tonic-xds): consume immediate first tick in OD housekeeping actor#2689
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gu0keno0 merged 2 commits intoJun 16, 2026
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`tokio::time::interval(period)` returns immediately on its first poll, so the actor was running `run_housekeeping` at t≈0 — before the data path had recorded anything. That early sweep called `snapshot_and_reset` on whatever counters had landed, zeroing them. In tests this surfaces as a race: `test_outlier_detection_reinsert_preserves_state` flakes with `(0, 0) != (3, 0)` when the actor's first tick fires after the test records its 3 calls but before the assertion reads counters. In production this silently drops the first interval's worth of outcomes on every endpoint. Fix: consume the immediate tick before entering the loop so the first real sweep happens one full `interval` after spawn, matching what the gRFC A50 sweep semantics expect. Verified the test passes 10/10 under stress.
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Thanks for the fix. maybe https://docs.rs/tokio/latest/tokio/time/fn.interval_at.html is a better way? |
gu0keno0
approved these changes
Jun 16, 2026
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Summary
A flaky test was reported (link) after #2619 was merged.
The root cause is:
tokio::time::interval(period)fires immediately on its first poll, so the outlier-detection housekeeping actor was runningrun_housekeepingat t≈0 — before the data path had recorded anything. That early sweep callssnapshot_and_resetand zeros whatever counters have landed. Therefore,test_outlier_detection_reinsert_preserves_stateflakes with(0, 0) != (3, 0)when the actor's first tick races the assertion read.Fix: consume the immediate tick before entering the loop so the first real sweep fires one full
intervalafter spawn, matching the gRFC A50 semantics.Testing
`cargo test -p tonic-xds --lib test_outlier_detection_reinsert_preserves_state` — 10/10 pass under stress.