chore: release v0.27.12

internal/pskr/pskr.go

@@ -140,8 +140,17 @@ func New(cfg Config) *Watcher {
 // same measurement is 0.2 to 1.2 — the load follows distance, which is what the
 // feed is actually about, and it is the same for every operator.
 func (w *Watcher) topics() []string {
+	bands := w.cfg.Bands
+	// One subscription per band per square multiplies, and past a point the
+	// cheaper trade is to take every band from those squares and drop the
+	// unwanted ones here: four bands over six hundred squares is 2400
+	// subscriptions, where "+" is 600 for maybe three times the messages —
+	// which are then filtered locally, as they already are for everything else.
+	if len(bands) > 1 && len(bands)*len(w.cfg.RxGrids) > 1000 {
+		bands = []string{"+"}
+	}
 	out := []string{}
-	for _, b := range w.cfg.Bands {
+	for _, b := range bands {
 		if len(w.cfg.RxGrids) == 0 {
 			out = append(out, "pskr/filter/v2/"+b+"/#")
 			continue
@@ -181,13 +190,30 @@ func (w *Watcher) Start() error {
 
 	opts.OnConnect = func(c mqtt.Client) {
 		w.cfg.Logf("pskr: connected to %s", w.cfg.Broker)
-		for _, topic := range w.topics() {
-			if tok := c.Subscribe(topic, 0, w.handle); tok.Wait() && tok.Error() != nil {
-				w.cfg.Logf("pskr: subscribe %s failed: %v", topic, tok.Error())
+		topics := w.topics()
+		// In batches, not one at a time. Each Subscribe waits for its own
+		// acknowledgement, which is fine for the nine squares this started with
+		// and is minutes of waiting for the six hundred a 2000 km radius asks
+		// for — during which the feed is only partly subscribed and the panel
+		// looks broken.
+		const batch = 100
+		subbed := 0
+		for i := 0; i < len(topics); i += batch {
+			end := i + batch
+			if end > len(topics) {
+				end = len(topics)
+			}
+			filters := make(map[string]byte, end-i)
+			for _, t := range topics[i:end] {
+				filters[t] = 0
+			}
+			if tok := c.SubscribeMultiple(filters, w.handle); tok.Wait() && tok.Error() != nil {
+				w.cfg.Logf("pskr: subscribing to %d topics failed: %v", len(filters), tok.Error())
 				continue
 			}
-			w.cfg.Logf("pskr: watching %s", topic)
+			subbed += len(filters)
 		}
+		w.cfg.Logf("pskr: watching %d topics (%d bands × %d receiver squares)", subbed, len(w.cfg.Bands), max(len(w.cfg.RxGrids), 1))
 	}
 	opts.OnConnectionLost = func(_ mqtt.Client, err error) {
 		w.mu.Lock()