New album-cover and artist-art source implementing
AlbumCoverProvider, ArtistArtProvider, and TestableProvider. Hits
the documented /album-mb.php and /artist-mb.php JSON endpoints by
MBID, then GETs the returned image URLs (CDN, key-less). 2 req/sec
rate limit per the upstream's documented free/test-key tier;
mutex+lastCall serialises ALL HTTP calls regardless of method so
JSON metadata fetches and image GETs share the same budget.
429 / 5xx triggers exponential backoff with jitter (250ms × 2^attempt
± 20%) up to 3 retries before surfacing ErrTransient. 401 / 403
surface as ErrTransient (auth issues are config errors, not "this
album has no art" — the row stays NULL across passes so the operator
sees pending count not decreasing as the diagnostic signal).
Artist art is atomic at the JSON metadata step (one round-trip
yields both URLs); the two image GETs are independent — partial
success returns whatever bytes landed and ErrNotFound only if
neither URL is present in the response.
Configure() falls back to the documented public test key (2) when
the operator's APIKey is empty, per the no-coercive-settings
principle. Test connection hits a stable popular release MBID
(Pink Floyd, "The Dark Side of the Moon").
theAudioDBBaseURL is a var (not const) so tests can override it.
Adapts the existing Fetcher-based MBCAA client to the new Provider
abstraction. mbcaaProvider embeds *Fetcher and implements
Provider + AlbumCoverProvider + TestableProvider. init() registers a
default-config instance; NewMBCAAProviderFromConfig swaps in
production config (User-Agent, MinPeriod) at boot.
Wrapper approach (rather than reimplementing the HTTP logic) keeps
the package compiling during the T4–T8 window: enricher.go and
main.go still reference the legacy Fetcher type / NewFetcher
constructor / Fetch method, all of which remain unchanged in
fetcher.go. A-T8 will consolidate the HTTP logic into this file and
delete fetcher.go after the enricher rewrite removes the last
legacy call sites.
TestConnection hits a hardcoded popular release MBID (Beatles
"Abbey Road" UK release) and treats both 200 and 404 as "connection
works" — MBCAA needs no auth, so only 5xx / network failures
surface. Tests cover ID/DisplayName/Capability metadata, success
path, 404→ErrNotFound, disabled-returns-ErrNotFound, Configure
toggle, TestConnection variants, and NewMBCAAProviderFromConfig
swap.
Defines the abstraction every cover-art source will implement:
- Provider — base interface (ID, DisplayName, RequiresAPIKey,
DefaultEnabled, Configure).
- AlbumCoverProvider — opt-in capability for fetching album covers
by MBID.
- ArtistArtProvider — opt-in capability for fetching artist thumb +
fanart atomically by MBID.
- TestableProvider — opt-in capability for the admin Test-Connection
button.
Sentinel ErrNotTestable / ErrProviderNotFound. ErrNotFound and
ErrTransient stay in fetcher.go for now; they move into provider.go
in the next commit when fetcher.go is deleted as part of the MBCAA
refactor.
Compile-time registry: providers register from init() in their own
file. Duplicate IDs panic at startup (compiled-in registration is a
build-time bug, not a runtime concern).
Tests cover: Register adds, duplicate panics, ProviderByID success
+ ErrProviderNotFound, capability-interface filtering via Go type
assertion.
Adds internal/library/scanrun.go with RunScan, which creates a scan_runs
row and sequences file-walk → MBID backfill → cover enrich, persisting
per-stage tallies as jsonb. Extends coverart.EnrichBatch to return
(processed, succeeded, failed, err) so the orchestrator can classify
outcomes. Replaces main.go's two separate boot goroutines with a single
RunScan call; passes nil scanner in the no-startup-scan branch.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
- gofmt -s on system.go, system_cron.go, api.go
- rename unused r → _ in 3 fetcher_test.go HTTP handlers
- TrackRow +queue test uses /add .* to queue/i (track-aware aria-label from #377)
- /library/artists page test mocks likes + tanstack-query (ArtistCard now embeds LikeButton)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
bvandeusen