ADR-0004: Discographies Are Enriched Once from MusicBrainz, in the Background, and Kept


Status	Proposed — until EdS’s voiced asks for an album by its place and no request waits on MusicBrainz
Date	2026-10-24
Scope	How an artist’s studio albums, the names they go by, and their albums’ other names come into the inventory, and how “their Nth album” is answered from it. Not covers, which are enrichment too and a later decision.
Takes over	EdS ADR-0041 and EdS ADR-0045, whose counting and fallback this carries over

Context

“Play Genesis’ first album” needs the order an artist’s albums came out in, and a library cannot give it: its years are often a reissue’s, and its first album may be under a reissue’s name (And The Word Was, for From Genesis to Revelation). EdS’s voiced asks MusicBrainz while the request waits (EdS ADR-0041), and on 2026-10-24 that took 13 and 17 seconds, with half the calls failing (EdS CHG-0041).

Options considered

Enrich in the background, once, and keep it. The inventory asks MusicBrainz for each artist the owner has, at MusicBrainz’s pace, and answers from what it kept.

Ask when asked, as voiced does: always current, and always as slow and as unreliable as MusicBrainz is at that moment.

Order by the library’s years. No outside service, and wrong wherever a reissue’s year stands in for the album’s.

Decision

inventoryd enriches the owner’s artists from MusicBrainz in the background, keeps what it finds, and answers “their Nth album” from the inventory alone.

What is kept, for each artist with an album that is not a compilation: the artist as MusicBrainz names them and the aliases it keeps (“Leonard Skinner” is Lynyrd Skynyrd); their studio albums, oldest first, by EdS’s rules (an album with no secondary type, an official release, credited to the artist alone); and, only while one of the owner’s albums is not found among them under its own name, the names their releases have gone by, at most eight albums an artist.
One owned album is one studio album. Each studio album’s own title is looked for first; another name is used only where its own is not found, and never a name that is another studio album’s own: a release of Genesis' first is titled “Genesis”, which is their 1983 album.
“No such artist” and “no studio albums” are answers, kept, and the owner’s albums are then counted by year. A failure to ask is not an answer: nothing is kept, and the artist is asked for again after a pause.
Asked first: an artist a client asks about who is not enriched yet. Then the rest, never-asked first, one at a time, a call each 1.5 s, and each asked again after thirty days.
The contract gains /v1/artists/{id}/albums/nth (the Nth owned, the album counted, and the owner’s albums after it) and /v1/artists/{id}/discography. An artist is found by their aliases too.
INV_MUSICBRAINZ=off enriches nothing.

Consequences

The first pass over a library takes hours: some 1,900 artists at two or three calls each, a call each 1.5 s. Until an artist is enriched, their Nth album is counted by the library’s years, and the answer says so ("order": "library").
A discography is up to a month old. A new album is found when the artist is asked for again.
MusicBrainz is asked from the workload, with a User-Agent naming eds-inventory, and only from there.
EdS’s voiced can stop asking MusicBrainz: its discographies, its alias lookup and its kept file go once it asks the inventory.

What would settle it

EdS’s voiced asks the inventory for “their first album” and plays the answer in under a second.