rewrite MongoCache with Scaffeine

app/controllers/User.scala

@@ -200,7 +200,7 @@ object User extends LilaController {
   def topWeek = Open { implicit ctx =>
     negotiate(
       html = notFound,
-      api = _ => env.cached.topWeek(true).map { users =>
+      api = _ => env.cached.topWeek(()).map { users =>
       Ok(Json toJson users.map(env.jsonView.lightPerfIsOnline))
     })
   }

app/mashup/Preload.scala

@@ -16,7 +16,7 @@ import play.api.libs.json._
 
 final class Preload(
     tv: Tv,
-    leaderboard: Boolean => Fu[List[User.LightPerf]],
+    leaderboard: Unit => Fu[List[User.LightPerf]],
     tourneyWinners: Fu[List[Winner]],
     timelineEntries: String => Fu[List[Entry]],
     streamsOnAir: () => Fu[List[StreamOnAir]],
@@ -40,7 +40,7 @@ final class Preload(
       simuls zip
       tv.getBestGame zip
       (ctx.userId ?? timelineEntries) zip
-      leaderboard(true) zip
+      leaderboard(()) zip
       tourneyWinners zip
       dailyPuzzle() zip
       streamsOnAir() zip

modules/game/src/main/Cached.scala

@@ -11,12 +11,12 @@ final class Cached(
     mongoCache: MongoCache.Builder,
     defaultTtl: FiniteDuration) {
 
-  def nbImportedBy(userId: String): Fu[Int] = count(Query imported userId)
-  def clearNbImportedByCache(userId: String) = count.remove(Query imported userId)
+  def nbImportedBy(userId: String): Fu[Int] = countCache(Query imported userId)
+  def clearNbImportedByCache(userId: String) = countCache.remove(Query imported userId)
 
   def nbPlaying(userId: String): Fu[Int] = countShortTtl(Query nowPlaying userId)
 
-  def nbTotal: Fu[Int] = count($empty)
+  def nbTotal: Fu[Int] = countCache($empty)
 
   private implicit val userHandler = User.userBSONHandler
 
@@ -29,7 +29,7 @@ final class Cached(
     f = (o: Bdoc) => coll countSel o,
     timeToLive = 5.seconds)
 
-  private val count = mongoCache(
+  private val countCache = mongoCache(
     prefix = "game:count",
     f = (o: Bdoc) => coll countSel o,
     timeToLive = defaultTtl,

modules/memo/src/main/MongoCache.scala

@@ -1,40 +1,44 @@
 package lila.memo
 
+import com.github.blemale.scaffeine.{ Scaffeine, Cache }
 import org.joda.time.DateTime
 import reactivemongo.bson._
 import reactivemongo.bson.Macros
 import scala.concurrent.duration._
-import spray.caching.{ LruCache, Cache }
 
 import lila.db.BSON.BSONJodaDateTimeHandler
 import lila.db.dsl._
 
 final class MongoCache[K, V: MongoCache.Handler] private (
     prefix: String,
-    expiresAt: () => DateTime,
-    cache: Cache[V],
+    cache: Cache[K, Fu[V]],
+    mongoExpiresAt: () => DateTime,
     coll: Coll,
     f: K => Fu[V],
     keyToString: K => String) {
 
-  def apply(k: K): Fu[V] = cache(k) {
+  def apply(k: K): Fu[V] = cache.get(k, k =>
     coll.find(select(k)).uno[Entry] flatMap {
       case None => f(k) flatMap { v =>
-        coll.insert(makeEntry(k, v)) recover
-          lila.db.recoverDuplicateKey(_ => ()) inject v
+        persist(k, v) inject v
       }
       case Some(entry) => fuccess(entry.v)
+    })
+
+  def remove(k: K): Funit = {
+    val fut = f(k)
+    cache.put(k, fut)
+    fut flatMap { v =>
+      persist(k, v).void
     }
   }
 
-  def remove(k: K): Funit =
-    coll.remove(select(k)).void >>- (cache remove k)
-
   private case class Entry(_id: String, v: V, e: DateTime)
 
   private implicit val entryBSONHandler = Macros.handler[Entry]
 
-  private def makeEntry(k: K, v: V) = Entry(makeKey(k), v, expiresAt())
+  private def persist(k: K, v: V): Funit =
+    coll.insert(Entry(makeKey(k), v, mongoExpiresAt())).void recover lila.db.recoverDuplicateKey(_ => ())
 
   private def makeKey(k: K) = s"$prefix:${keyToString(k)}"
 
@@ -45,22 +49,28 @@ object MongoCache {
 
   private type Handler[T] = BSONHandler[_ <: BSONValue, T]
 
-  private def expiresAt(ttl: Duration)(): DateTime =
-    DateTime.now plusSeconds ttl.toSeconds.toInt
+  // expire in mongo 3 seconds before in heap,
+  // to make sure the mongo cache is cleared
+  // when the heap value expires
+  private def mongoExpiresAt(ttl: FiniteDuration): () => DateTime = {
+    val seconds = ttl.toSeconds.toInt - 3
+    () => DateTime.now plusSeconds seconds
+  }
 
   final class Builder(coll: Coll) {
 
     def apply[K, V: Handler](
       prefix: String,
       f: K => Fu[V],
-      maxCapacity: Int = 512,
-      initialCapacity: Int = 64,
+      maxCapacity: Int = 1024,
       timeToLive: FiniteDuration,
-      timeToLiveMongo: Option[FiniteDuration] = None,
       keyToString: K => String): MongoCache[K, V] = new MongoCache[K, V](
       prefix = prefix,
-      expiresAt = expiresAt(timeToLiveMongo | timeToLive),
-      cache = LruCache(maxCapacity, initialCapacity, timeToLive),
+      cache = Scaffeine()
+        .expireAfterWrite(timeToLive)
+        .maximumSize(maxCapacity)
+        .build[K, Fu[V]],
+      mongoExpiresAt = mongoExpiresAt(timeToLive),
       coll = coll,
       f = f,
       keyToString = keyToString)
@@ -68,11 +78,13 @@ object MongoCache {
     def single[V: Handler](
       prefix: String,
       f: => Fu[V],
-      timeToLive: FiniteDuration,
-      timeToLiveMongo: Option[FiniteDuration] = None) = new MongoCache[Boolean, V](
+      timeToLive: FiniteDuration) = new MongoCache[Unit, V](
       prefix = prefix,
-      expiresAt = expiresAt(timeToLiveMongo | timeToLive),
-      cache = LruCache(timeToLive = timeToLive),
+      cache = Scaffeine()
+        .expireAfterWrite(timeToLive)
+        .maximumSize(1)
+        .build[Unit, Fu[V]],
+      mongoExpiresAt = mongoExpiresAt(timeToLive),
       coll = coll,
       f = _ => f,
       keyToString = _.toString)

modules/tournament/src/main/TournamentStats.scala

@@ -18,8 +18,7 @@ final class TournamentStatsApi(mongoCache: lila.memo.MongoCache.Builder) {
     prefix = "tournament:stats",
     keyToString = identity,
     f = fetch,
-    timeToLive = 10 minutes,
-    timeToLiveMongo = 90.days.some)
+    timeToLive = 10 minutes)
 
   private def fetch(tournamentId: Tournament.ID): Fu[TournamentStats] = for {
     rating <- PlayerRepo.averageRating(tournamentId)

modules/tournament/src/main/WinnersApi.scala

@@ -116,12 +116,12 @@ final class WinnersApi(
     f = fetchAll,
     timeToLive = ttl)
 
-  def all: Fu[AllWinners] = allCache(true)
+  def all: Fu[AllWinners] = allCache(())
 
   // because we read on secondaries, delay cache clear
   def clearCache(tour: Tournament) =
     if (tour.schedule.exists(_.freq.isDailyOrBetter))
-      scheduler.once(5.seconds) { allCache.remove(true) }
+      scheduler.once(5.seconds) { allCache.remove(()) }
 
 }