feat(#392): SSE event stream foundation — eventbus + /api/events/stream

Slice 1 of the #392 hybrid live-refresh work. Ships the in-process pub/sub
bus and the SSE subscriber endpoint; no producers wired yet, so the stream
emits only heartbeats today. Verifiable in isolation by curl-ing the
endpoint with a valid Bearer token — the connection opens, ": heartbeat"
lines arrive every 15s, the connection closes cleanly on client disconnect.

eventbus.Bus is a small fan-out broadcaster: subscribers register through
Subscribe (returns a receive channel + an unsubscribe closure), writers
call Publish, and the bus drops events for any subscriber whose buffer is
full rather than blocking the writer. No persistence — clients are
expected to resync via normal /api/* fetches on (re)connect.

The SSE handler emits an initial ": connected" comment so the client sees
the connection open immediately, then forwards events whose UserID matches
the authenticated user (or is empty for broadcast). Heartbeat comments
keep proxy connections alive. Context cancellation cleanly tears down the
subscription on client disconnect.

Producers (likes, request status, quarantine, scanner, playlist mutations)
land in subsequent slices.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-05-12 20:44:37 -04:00
parent b466b6494a
commit 170614baf1
5 changed files with 394 additions and 2 deletions
+5 -1
View File
@@ -14,6 +14,7 @@ import (
"git.fabledsword.com/bvandeusen/minstrel/internal/auth"
"git.fabledsword.com/bvandeusen/minstrel/internal/config"
"git.fabledsword.com/bvandeusen/minstrel/internal/coverart"
"git.fabledsword.com/bvandeusen/minstrel/internal/eventbus"
"git.fabledsword.com/bvandeusen/minstrel/internal/library"
"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrconfig"
"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrquarantine"
@@ -27,7 +28,7 @@ import (
// Mount attaches /api/* handlers to r. Public endpoints (login) are outside
// RequireUser; everything else is gated by the middleware. The events writer
// is shared with the Subsonic mount so /rest/scrobble feeds the same store.
func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, events *playevents.Writer, recCfg config.RecommendationConfig, lidarrCfg *lidarrconfig.Service, lidarrReqs *lidarrrequests.Service, lidarrQuar *lidarrquarantine.Service, tracksSvc *tracks.Service, playlistsSvc *playlists.Service, coverEnricher *coverart.Enricher, coverBackfillCap int, coverSettings *coverart.SettingsService, scanner *library.Scanner, scanCfg library.RunScanConfig, scheduler *library.Scheduler, dataDir string, sender mailer.Sender) {
func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, events *playevents.Writer, recCfg config.RecommendationConfig, lidarrCfg *lidarrconfig.Service, lidarrReqs *lidarrrequests.Service, lidarrQuar *lidarrquarantine.Service, tracksSvc *tracks.Service, playlistsSvc *playlists.Service, coverEnricher *coverart.Enricher, coverBackfillCap int, coverSettings *coverart.SettingsService, scanner *library.Scanner, scanCfg library.RunScanConfig, scheduler *library.Scheduler, dataDir string, sender mailer.Sender, bus *eventbus.Bus) {
rng := rand.New(rand.NewSource(rand.Int63()))
h := &handlers{
pool: pool, logger: logger, events: events, recCfg: recCfg,
@@ -45,6 +46,7 @@ func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, events *playev
scheduler: scheduler,
dataDir: dataDir,
mailer: sender,
eventbus: bus,
}
r.Route("/api", func(api chi.Router) {
@@ -79,6 +81,7 @@ func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, events *playev
authed.Get("/discover/suggestions", h.handleListSuggestions)
authed.Get("/home", h.handleGetHome)
authed.Post("/events", h.handleEvents)
authed.Get("/events/stream", h.handleEventsStream)
authed.Post("/likes/tracks/{id}", h.handleLikeTrack)
authed.Delete("/likes/tracks/{id}", h.handleUnlikeTrack)
authed.Post("/likes/albums/{id}", h.handleLikeAlbum)
@@ -191,4 +194,5 @@ type handlers struct {
scheduler *library.Scheduler
dataDir string
mailer mailer.Sender
eventbus *eventbus.Bus
}