fix(activitypub): fixes #4372 where excessive AP resource use disrupts video delivery (#4552)

activitypub/activitypub.go

@@ -1,8 +1,6 @@
 package activitypub
 
 import (
-	"math"
-
 	"github.com/owncast/owncast/activitypub/crypto"
 	"github.com/owncast/owncast/activitypub/inbox"
 	"github.com/owncast/owncast/activitypub/outbox"
@@ -36,14 +34,32 @@ func Start(datastore *data.Datastore) {
 }
 
 func getOutboundWorkerPoolSize() int {
+	// Use a reasonable fixed worker pool size instead of scaling with followers
+	// This prevents excessive resource usage when streamers have many followers
+	const (
+		minWorkers     = 10 // Minimum workers for small instances
+		maxWorkers     = 50 // Maximum workers to prevent resource exhaustion
+		defaultWorkers = 20 // Default for most instances
+	)
+
 	var followerCount int64
 	fc, err := persistence.GetFollowerCount()
 	if err != nil {
 		log.Errorln("Unable to get follower count", err)
-		fc = 50 // Arbitrary fallback value.
+		return defaultWorkers
 	}
-	followerCount = int64(math.Max(float64(fc), 50))
-	return int(followerCount * 5)
+	followerCount = fc
+
+	// Scale more conservatively: start with base workers, add 1 worker per 100 followers
+	// This gives a much more reasonable scaling than the previous followerCount * 5
+	workers := minWorkers + int(followerCount/100)
+
+	if workers > maxWorkers {
+		workers = maxWorkers
+	}
+
+	log.Infof("Initializing ActivityPub outbound worker pool with %d workers for %d followers", workers, followerCount)
+	return workers
 }
 
 // SendLive will send a "Go Live" message to followers.