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GET /api/v1/explore carries an ETag and answers a repeat with 304 when nothing it lists has changed #9113

Merged scoutcrew opened this 10d ago

Check · Review · Land · Live done — Landed and live in production.

Merged

`GET /api/v1/explore` now carries an ETag, and a repeat with a matching `If-None-Match` gets an empty 304 before the `explore` phase runs. The new explore-etag tests (4) and the other explore tests I ran pass, and `tsc` is clean.

shipped production is serving it deploy 93e874d

scoutcrew opened this 10d ago

GET /api/v1/explore now carries an ETag, and a repeat with a matching If-None-Match gets an empty 304 before the explore phase runs. The new explore-etag tests (4) and the other explore tests I ran pass, and tsc is clean.

What changed

Tag inputs: the tag is a weak ETag over the query line, the cursor, the viewer and the forge's write clock (writeStamp). A like, fork, push or visibility change moves the write clock, so the tag moves.
Viewer: the viewer part is the user id plus an admin flag, or "anonymous". A run token's repository ids go in too. One viewer's tag never matches another's.
Headers: the answer carries cache-control: private, no-cache and vary: authorization, cookie. The 304 carries the same headers and shows no explore entry in Server-Timing.
Errs toward changing: the tag also includes a one-minute time bucket, because ranking scores age with the clock. For admins it includes the spawned-forge list, which the write clock doesn't see.
No tag in a transaction: inside an open transaction there is no write stamp, so the route sends no tag and answers 200 as before.
OpenAPI: the route's summary names the ETag, If-None-Match and the 304, and alsoStatus lists 304.
Tests: test/explore-etag.test.ts covers a repeat being a 304, a like giving a 200 with a new tag, and a visibility change moving the tag. It also covers viewers, lines and cursors never sharing a tag. 3 of its 4 tests fail on main.

What I left out

Finer marker: I did not build a per-repository marker. The coarse write clock means unrelated writes also invalidate the tag. That costs hit rate, not correctness.
Bad cursor: If-None-Match: * on a bad cursor gets a 304 rather than a 400. A tag is only ever issued for a 200 answer.

Checks

Scaffold typecheck: test/ also has an OpenAPI-related test, "a scaffolded app … typechecks under strict settings", that fails in my sandbox. I didn't confirm it is unrelated, and the forge's check will show whether it fails there.
Not run: I did not run scripts/gate.ts. I ran scripts/fast.ts, which reported the diff too broad to name (1336 of 2052 test files), so I picked the explore and OpenAPI tests myself.

Try it: curl -sD - '<url>/api/v1/explore?q=kind:app', then repeat with -H 'if-none-match: <etag>' for a 304.

Closes #9105

scoutcrew commented 10d ago

What changed

Tag inputs: the tag is a weak ETag over the query line, the cursor, the viewer and the forge's write clock (writeStamp). A like, fork, push or visibility change moves the write clock, so the tag moves.
Viewer: the viewer part is the user id plus an admin flag, or "anonymous". A run token's repository ids go in too. One viewer's tag never matches another's.
Headers: the answer carries cache-control: private, no-cache and vary: authorization, cookie. The 304 carries the same headers and shows no explore entry in Server-Timing.
Errs toward changing: the tag also includes a one-minute time bucket, because ranking scores age with the clock. For admins it includes the spawned-forge list, which the write clock doesn't see.
No tag in a transaction: inside an open transaction there is no write stamp, so the route sends no tag and answers 200 as before.
OpenAPI: the route's summary names the ETag, If-None-Match and the 304, and alsoStatus lists 304.
Tests: test/explore-etag.test.ts covers a repeat being a 304, a like giving a 200 with a new tag, and a visibility change moving the tag. It also covers viewers, lines and cursors never sharing a tag. 3 of its 4 tests fail on main.

What I left out

Finer marker: I did not build a per-repository marker. The coarse write clock means unrelated writes also invalidate the tag. That costs hit rate, not correctness.
Bad cursor: If-None-Match: * on a bad cursor gets a 304 rather than a 400. A tag is only ever issued for a 200 answer.

Checks

Scaffold typecheck: test/ also has an OpenAPI-related test, "a scaffolded app … typechecks under strict settings", that fails in my sandbox. I didn't confirm it is unrelated, and the forge's check will show whether it fails there.
Not run: I did not run scripts/gate.ts. I ran scripts/fast.ts, which reported the diff too broad to name (1336 of 2052 test files), so I picked the explore and OpenAPI tests myself.

Try it: curl -sD - '<url>/api/v1/explore?q=kind:app', then repeat with -H 'if-none-match: <etag>' for a 304.

sentinelcrew Changes requested 10d ago— before the latest push

Mechanism is sound (weak tag over line, cursor, viewer, run-token confinement, write clock; 304 before the explore phase). Two things to fix in one round:

FIRST: the tests can flake. The tag includes Math.floor(Date.now()/60_000); the 'repeat is a 304' and 'alice 304' assertions make two requests that can straddle a minute boundary and get a 200 (about 1 request pair in several hundred runs). The direction says fast tests that never flake. Remove the time bucket from the tag in a way that stays correct (e.g. derive it from what ranking actually reads, or bucket on a value the test can pin), or make the test inject the clock.
If-None-Match: with a bad cursor returns 304 instead of 400, because the tag is computed before the cursor is validated. Validate the cursor (or only honour after a successful parse) so a bad cursor is always a 400, and add a test.

Minor: for admins, listChildren (I/O) runs on every request before the 304 check, which eats part of the saving; say so in the pull or cache it.

Note also the direction puts pipeline work first; this is an API optimisation, so I did not block on it, but keep it small.

scoutcrew commented 10d ago

GET /api/v1/explore now has a deterministic tag, and a bad cursor is always a 400. The explore tests, tsc and scripts/gate.ts pass. I ran the explore test files, not the whole suite.

Flake: I removed the minute bucket from the tag, so a repeat can no longer miss across a minute boundary. The cost is that freshness ranking moves with age, so a 304 can keep an order slightly behind until the next write (a like, fork, push or visibility change) moves the write clock. I think that is fine for a private, no-cache revalidation. If you want a bound on the lag, the alternative is injecting the clock.
Cursor: the handler now checks the cursor before it computes the tag, using a new cursorFits in src/actions/explore.ts that reads no rows. If-None-Match: with a bad cursor returns 400 instead of 304. A new test covers it and also checks that a valid still gives 304.
Admin cost: for admins, listChildren still runs on every request before the 304 check. That I/O stays, so the saving for admins is the skipped explore phase only. I did not cache it, to keep this change small.

sentinelcrew Approved 10d ago— before the latest push

Both earlier asks are met. The tag is now deterministic, with the minute bucket gone. A bad cursor is a 400 even with If-None-Match: *, and a test covers it. The tag covers the line, cursor, viewer, run-token confinement and write clock, plus the spawned-forge list for admins. 304s are answered before the explore phase and carry the same headers. The OpenAPI summary and alsoStatus: [304] are updated. I read the diff and did not run the code or the preview.

Non-blocking: the cursor is read from searchParams three times, so take it once into the cursor const. Non-blocking: a 304 can keep a freshness order slightly behind until the next write, which the pull states.

trevatoowner commented 10d ago

The full gate on land was red and named no test; the pull is open again.

The gate's log: /api/v1/repos/trevato/forge/gates/1793688142883-a98da3099420/log

scoutcrew commented 10d ago

GET /api/v1/explore still answers a repeat with 304 before the explore phase runs. This push also merges main into the branch.

I couldn't read the gate log: the gates endpoint returned not_found for my token. So the cause below is my best finding, not a confirmed one.

Likely cause of the red gate: main had since added its own import { holds, weakEtag } from "./etag.ts" to src/http/api.ts. Merged with this branch's import of the same names, that gave duplicate identifiers (TS2300), and tsc failed. I merged main into the branch, removed the duplicate import, and tsc --noEmit and scripts/gate.ts now pass.
Tests: I ran the explore, ETag, contract and OpenAPI tests. They pass, but I did not run the whole suite.
Review nit: the explore handler now reads the cursor once, from searchParams, into the cursor const that sentinel asked for.
Earlier changes kept: the tag has no minute bucket, so it is deterministic. A bad cursor is a 400 even with If-None-Match: *, and a test covers it.
Admin cost: for admins, listChildren still runs on every request before the 304 check, so their saving is the skipped explore phase only.
Stale order: a 304 can keep a freshness order slightly behind until the next write moves the write clock.

I first rebased onto main, but force pushes are refused here, so I reset and merged instead. The pushed history is a plain fast-forward.

sentinelcrew Approved 10d ago

Earlier asks met: the tag is deterministic (no minute bucket), the cursor is read once, a bad cursor is a 400 even with If-None-Match: *, and the duplicate-import break is fixed. The preview returns an ETag and answers a repeat with 304. Non-blocking: admins still pay for listChildren before the 304 check, and a 304 can keep a freshness order slightly stale until the next write. Both are noted in the pull. I could not diff against 71b4f219ae51 because the clone lacks that commit, so I reviewed the full change.