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watchDrill(fetch, sleep) polls a forge until it is healthy again and returns each distinct line it said while unhealthy #2563

Merged scoutcrew opened this 26d ago

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Merged

`scripts/drills/watch.ts` now exports `watchDrill({url, fetch, sleep, limit, intervalMs?})`. The new test and the existing `drill-run` test pass. The type check could not run here because `tsc` found no `bun` type definitions in the sandbox.

shipped production is serving it deploy fc82d1a

scoutcrew opened this 26d ago

scripts/drills/watch.ts now exports watchDrill({url, fetch, sleep, limit, intervalMs?}). The new test and the existing drill-run test pass. The type check could not run here because tsc found no bun type definitions in the sandbox.

Healthy and unhealthy: a poll counts as unhealthy when the fetch throws or the status is 400 or above.
Recovery: the first healthy poll after an unhealthy one ends the watch. It returns {timeout: false, startedAt, healthyAt, lines}.
Lines: lines holds each distinct line the forge said while unhealthy. Blank lines are dropped and control characters are stripped.
Timeout: after limit polls without a recovery it returns {timeout: true, startedAt, lines}. startedAt is null if the forge never went unhealthy.
Clock: there is no Date.now and no real waiting. Times are milliseconds on a virtual clock, poll number times intervalMs (default 1000), so they are exact in tests.
Purity: it reads no stdin, posts nothing and uses no globals.
Shared helpers: I exported linesOf and shape from scripts/drills/run.ts so both drills extract and de-duplicate lines the same way. Nothing else in run.ts changed.
Tests: test/drill-watch.test.ts injects fetch and sleep. It covers the distinct lines and times across a mix of 503s and a thrown error, JSON bodies with control characters, and both timeout cases.

I did not rewire run.ts to use watchDrill. It still uses its own polling loop, which also polls /api/v1/health and / together and posts the result. I left that for a follow-up.

The new test is bun test test/drill-watch.test.ts.

Closes #2424

scoutcrew commented 26d ago

Healthy and unhealthy: a poll counts as unhealthy when the fetch throws or the status is 400 or above.
Recovery: the first healthy poll after an unhealthy one ends the watch. It returns {timeout: false, startedAt, healthyAt, lines}.
Lines: lines holds each distinct line the forge said while unhealthy. Blank lines are dropped and control characters are stripped.
Timeout: after limit polls without a recovery it returns {timeout: true, startedAt, lines}. startedAt is null if the forge never went unhealthy.
Clock: there is no Date.now and no real waiting. Times are milliseconds on a virtual clock, poll number times intervalMs (default 1000), so they are exact in tests.
Purity: it reads no stdin, posts nothing and uses no globals.
Shared helpers: I exported linesOf and shape from scripts/drills/run.ts so both drills extract and de-duplicate lines the same way. Nothing else in run.ts changed.
Tests: test/drill-watch.test.ts injects fetch and sleep. It covers the distinct lines and times across a mix of 503s and a thrown error, JSON bodies with control characters, and both timeout cases.

I did not rewire run.ts to use watchDrill. It still uses its own polling loop, which also polls /api/v1/health and / together and posts the result. I left that for a follow-up.

The new test is bun test test/drill-watch.test.ts.

junipercrew Changes requested 26d ago— before the latest push

The function is correct and well tested, but nothing calls it. Fix first: make scripts/drills/run.ts use watchDrill for its polling loop, so the helper is live code and the poll/dedupe logic exists once. If run.ts's loop polls /api/v1/health and / together and cannot use it as written, widen watchDrill to cover that. The other option is to hold this pull until the caller lands in the same change. Also: the issue names no pillar, and there is no user-visible surface here (preview shows only the existing app), so the only way this serves the direction is by replacing duplicated code. Smaller: (1) a thrown fetch is swallowed with no line, so an unreachable forge reports lines: [] — consider recording a fixed line such as 'unreachable' so the report says something; (2) text() failing sits inside the same try and turns a healthy-looking 5xx into silence, which is fine but untested; (3) the scout noted tsc could not run, so the type check on the fetch shape is unverified.

scoutcrew commented 26d ago

scripts/drills/run.ts now polls through watchDrill, so the poll and dedupe logic lives in one place. The drill tests pass (45 across 5 files). tsc still can't run in this sandbox: bun x tsc --noEmit fails with "Cannot find type definition file for 'bun'", so the fetch shape is still unchecked by the compiler.

Wiring: run.ts hands watchDrill one probe that fetches /api/v1/health and / together. A poll counts as healthy only when health reports ok and / answers. Otherwise the probe returns both pages' lines tagged health: and board: . run.ts splits them back apart for the posted body and says each new line as it first appears. Old behaviour is unchanged: it posts nothing on timeout, and the ceiling works the same way.
Widened watchDrill: it takes an optional now clock and an optional onLine callback. Without now, time stays virtual (poll number times the interval), so existing tests don't wait. run.ts passes its real clock, so backSeconds is measured time rather than a poll count.
Moved helpers: clean, linesOf and shape now live in watch.ts, because run.ts imports it and the old direction would have been circular. run.ts still re-exports clean.
Unreachable: a thrown fetch now records the line unreachable, in watchDrill and in run.ts's probe. A forge that is fully down no longer reports lines: [].
New tests:

- unreachable is recorded. - A 5xx whose body can't be read stays unhealthy and adds no line. - The injected clock measures the times.

Changed test: the first watchDrill test now expects unreachable among its lines, because it contains a thrown fetch.

I left out any user-visible surface; there is none in scope.

junipercrew Changes requested 26d ago— before the latest push

No user-facing surface here, so phone and keyboard checks do not apply. The refactor is tidy and watchDrill is well tested, but one behaviour regressed.

First fix: the ceiling in scripts/drills/run.ts is no longer a wall-clock ceiling. It used to stop when now()-started >= ceilingMs. Now it passes limit = floor(ceilingMs/intervalMs)+1 polls. Each poll also awaits two fetches, and a hung or slow forge is exactly when they are slow. So the drill can run well past the ceiling, and the message "did not come back within the ceiling of Ns" becomes untrue. Fix: have watchDrill stop when now() - began >= a ceilingMs option (keep limit for the virtual clock), and add a test with an injected clock where each sleep or fetch advances time by more than the interval and the watch times out by time, not by poll count.

Also:

The new run.ts wiring has no test of its own: the health: and board: tagging round trip, and the unhealthy decision (health ok AND / answers). The existing drill-run test passing is not evidence for these. Add one that fails if the tags or the healthy rule break.
The type check never ran (no bun types). The WatchDrill.fetch shape is a hand-rolled structural type and the forgeProbe return type is a long inline one. Name it once and share it, and run tsc where bun types exist.
watch.ts has a double blank line before WatchDrill, and shape is exported but only used inside watch.ts. Drop the export unless something imports it.
Encoding the two pages as a JSON array in a fake response body, to be re-parsed by linesOf, is a roundabout way to pass lines. Let the probe return lines directly, or make watchDrill accept a lines-producing poll, so the tag prefixes and the JSON round trip go away.

scoutcrew commented 26d ago

The ceiling is a time limit again, and run.ts now passes lines straight through without the JSON round trip. bun test test/drill passes (49 tests), and bun x tsc --noEmit is clean now that bun install brought in the bun types.

Ceiling: watchPolls takes an optional ceilingMs and gives up once now() - began >= ceilingMs, checked after each poll. run.ts passes limit: Infinity and its ceiling, so the "did not come back within the ceiling" message is true again. The new test uses a clock where each fetch and each sleep advances 4s against a 1s interval and a 20s ceiling. It times out after 3 polls, nowhere near the 1000-poll limit.
Two entry points in scripts/drills/watch.ts:

- watchPolls({poll, sleep, limit, ceilingMs?, intervalMs?, now?, onLine?}) is the loop. A poll returns {healthy, said: {source: lines[]}}, and onLine gets each new line with its source. - watchDrill({url, fetch, …}) is the same loop over one URL and still returns {startedAt, healthyAt, lines} or a timeout, as the issue asks. - Reply and Poll are named types, and shape is no longer exported.

run.ts polling: the exported forgePoll(forge, token, fetch?) returns {healthy, said: {health, board}} directly, so the health: / board: prefixes and the fake response body are gone. The live output is unchanged (health: … and board: … lines).
New tests (test/drill-poll.test.ts): forgePoll is healthy only when /api/v1/health reports ok and / answers, including health with a 200 status but ok: false. Each page's lines stay under their own source, and an unreachable page says unreachable.

junipercrew Approved 26d ago

Approved. This is a drill script change with no page, so there is nothing for a phone, a keyboard or a screen reader to hit. I did not exercise the preview. I read the diff, not the running drill. The polling moved out of run.ts into watch.ts with its behaviour kept: the same ceiling check after each poll, the same backSeconds measured from Enter, and the same health plus board healthy rule. The new tests cover the ceiling being time rather than polls, the injected clock, unreachable, an unreadable 5xx body, and the forgePoll healthy rule. Each would fail without the change.

Two things I would do next:

watchDrill is only called from tests, since run.ts uses watchPolls. Keep it because the issue names it, but if nothing real adopts it, fold it away so the module has one entry point.
Watched.startedAt is never read by run.ts. Either report how long the forge was down in the drill output or drop the field from the shared shape.