CHG-0019: The Stand Is for Records


Date	2026-10-13
Change type	Upgrade
Status	In progress
Systems	`nowplayd` and `lightd` on the workload
How	`make -C deploy deploy WHERE=builder`
Risk	Low. Most likely to go wrong: a stand that is dark when someone expects it lit, and is taken for dead
Decisions	ADR-0028, which this is the evidence for
Related	CHG-0016, which gave the stand its idle scene; CHG-0015, whose beacon now decides between dim and dark

Summary

The stand was lit all day: dim whenever nothing played, and from iTunes' cover whenever iTunes did. It is an LP stand, and from this change it is lit by records only.

iTunes’ cover is published with the look dark, and the stand is sent dark for it. The cover screen and the console still show the cover.
With nothing playing the stand is dark, and dim only while the turntable’s beacon says the turntable is switched on.

Goal

iTunes playing, the turntable off: the stand dark, the sleeve on both screens.
The turntable switched on: the stand dim within seconds of the beacon connecting.
A record: lit from its sleeve, as before. Between its sides: dim.
The turntable switched off: dark within about half a minute.

Scope

In scope: nowplayd (one new setting, NP_DARK_SOURCES=itunes, and a look published when the room goes idle) and lightd (two looks it now draws).

Out of scope: every firmware, the agent Pi, the console, palette, the tenant. No topic is added and no broker account changes: the looks travel on nowplaying/current/look, which both services already have. The stand already renders brightness 0 as off.

Risk and impact

Risk	Where	Guard
A dark stand is taken for a dead one	the room	the console shows the stand’s presence and the scene it was sent, “solid · brightness 0%”
The two services disagree for a moment while restarting	the workload	they restart together; an old `lightd` lights a `dark` cover from its colors and refuses the look of no cover, which is how it was before
The beacon is stuck `online` and the stand stays dim	the room	switch the turntable on and off (ADR-0023)

Procedure

make -C deploy deploy WHERE=builder.

Verification

nowplayd logs that it publishes itunes with the look that lights nothing.
eds/nowplaying/current/look holds either a look that names no cover, or iTunes’ cover with "look":"dark".
The stand’s scene is solid at brightness 0 with the turntable off, and solid at 0.15 with it on and silent.

Undo

iTunes on the stand again: remove NP_DARK_SOURCES from deploy/nowplayd.env, and make -C deploy units.
Dim when idle again: deploy the commit before this one.

Outcome

When (UTC)	What happened
before	The first try did not start: the Mac was on the home network, with no way to the Builder. Its owner moved it.
12:45	Deployed (`e90b447`). All four services came back active, and `nowplayd` said it publishes `itunes` with the look that lights nothing. The beacon read `online`. But every source was offline - everything had been switched off the evening before, in the middle of a record - and `nowplayd` said nothing at all: the stand was lit again from the cover of that record, still retained from the day before, and the cover screen showed its sleeve.
12:47	A second commit, so that `nowplayd` decides when nobody is reporting as it starts (`1460a08`). Shipping it stopped at the first image: `podman save` on the Builder and `podman load` on the workload each waited on the other for nineteen minutes. Its owner killed both; the assistant was refused.
13:06	Shipped. Two seconds after starting, `nowplayd` published `current` as stopped with no source. Fifteen seconds after that it said idle, `switched_on=true`, and `lightd` published solid at 0.15 with `look=standby`. The stand reported applying it, and the console held no cover.

Departures

A fault that was not this change’s was found and mended in it. With every source offline, no winner is what nowplayd starts with, so nothing was decided and nothing published: whatever was current before a restart stood on its retained topics until a source came back. ADR-0024 says nobody reporting goes idle; started that way, it never did. nowplayd now decides once the retained messages are in.
Deployed from a worktree, with the tenant’s directory named by INFRA= and discogs.env copied in, as in CHG-0017.
The image load that hung is not explained. The same load took seconds twenty minutes earlier; both machines had been up for about that long.

Follow-ups

Dark has not been seen. The beacon was on throughout, so only dim was: the beacon switched off, and the stand’s scene at brightness 0.
iTunes playing with the turntable off: no source was online to try.
The five things ADR-0028 lists as not yet shown.