feat: add metrics for user registrations, logins, challenges, and game writebacks

modules/account/src/main/scala/de/nowchess/account/service/AccountService.scala

@@ -4,6 +4,7 @@ import de.nowchess.account.domain.{BotAccount, OfficialBotAccount, UserAccount}
 import de.nowchess.account.dto.{LoginRequest, RegisterRequest}
 import de.nowchess.account.error.AccountError
 import de.nowchess.account.repository.{BotAccountRepository, OfficialBotAccountRepository, UserAccountRepository}
+import io.micrometer.core.instrument.MeterRegistry
 import io.quarkus.elytron.security.common.BcryptUtil
 import io.smallrye.jwt.build.Jwt
 import jakarta.enterprise.context.ApplicationScoped
@@ -29,11 +30,21 @@ class AccountService:
 
   @Inject
   var officialBotAccountRepository: OfficialBotAccountRepository = uninitialized
+
+  @Inject
+  var meterRegistry: MeterRegistry = uninitialized
   // scalafix:on
 
   @Transactional
   def register(req: RegisterRequest): Either[AccountError, UserAccount] =
     log.infof("Registering user %s", req.username)
+    val result = registerAccount(req)
+    result match
+      case Right(_) => meterRegistry.counter("nowchess.users.registrations", "result", "success").increment()
+      case Left(_)  => meterRegistry.counter("nowchess.users.registrations", "result", "failure").increment()
+    result
+
+  private def registerAccount(req: RegisterRequest): Either[AccountError, UserAccount] =
     if userAccountRepository.findByUsername(req.username).isDefined then Left(AccountError.UsernameTaken(req.username))
     else if userAccountRepository.findByEmail(req.email).isDefined then
       Left(AccountError.EmailAlreadyRegistered(req.email))
@@ -48,6 +59,15 @@ class AccountService:
       Right(account)
 
   def login(req: LoginRequest): Either[AccountError, String] =
+    val result = authenticateUser(req)
+    result match
+      case Right(_)    => meterRegistry.counter("nowchess.auth.logins", "result", "success").increment()
+      case Left(error) =>
+        meterRegistry.counter("nowchess.auth.logins", "result", "failure").increment()
+        meterRegistry.counter("nowchess.auth.login.failures", "reason", loginFailureReason(error)).increment()
+    result
+
+  private def authenticateUser(req: LoginRequest): Either[AccountError, String] =
     userAccountRepository.findByUsername(req.username) match
       case None =>
         log.warnf("Login failed for unknown user %s", req.username)
@@ -69,6 +89,17 @@ class AccountService:
               .sign(),
           )
 
+  private def loginFailureReason(error: AccountError): String = error match
+    case AccountError.InvalidCredentials        => "invalid_credentials"
+    case AccountError.UserBanned                => "user_banned"
+    case AccountError.UsernameTaken(_)          => "username_taken"
+    case AccountError.EmailAlreadyRegistered(_) => "email_registered"
+    case AccountError.UserNotFound              => "user_not_found"
+    case AccountError.BotNotFound               => "bot_not_found"
+    case AccountError.BotLimitExceeded          => "bot_limit_exceeded"
+    case AccountError.NotAuthorized             => "not_authorized"
+    case AccountError.BotBanned                 => "bot_banned"
+
   def findByUsername(username: String): Option[UserAccount] =
     userAccountRepository.findByUsername(username)
 

modules/account/src/main/scala/de/nowchess/account/service/ChallengeService.scala

@@ -18,6 +18,7 @@ import de.nowchess.account.dto.{
 }
 import de.nowchess.account.error.ChallengeError
 import de.nowchess.account.repository.{ChallengeRepository, UserAccountRepository}
+import io.micrometer.core.instrument.MeterRegistry
 import jakarta.enterprise.context.ApplicationScoped
 import jakarta.inject.Inject
 import jakarta.transaction.Transactional
@@ -48,10 +49,22 @@ class ChallengeService:
 
   @Inject
   var eventPublisher: EventPublisher = uninitialized
+
+  @Inject
+  var meterRegistry: MeterRegistry = uninitialized
   // scalafix:on
 
   @Transactional
   def create(challengerId: UUID, destUsername: String, req: ChallengeRequest): Either[ChallengeError, Challenge] =
+    val result = createChallenge(challengerId, destUsername, req)
+    result.foreach(_ => meterRegistry.counter("nowchess.challenges.created").increment())
+    result
+
+  private def createChallenge(
+      challengerId: UUID,
+      destUsername: String,
+      req: ChallengeRequest,
+  ): Either[ChallengeError, Challenge] =
     for
       destUser <- userAccountRepository.findByUsername(destUsername).toRight(ChallengeError.UserNotFound(destUsername))
       challenger <- userAccountRepository.findById(challengerId).toRight(ChallengeError.ChallengerNotFound)
@@ -80,6 +93,11 @@ class ChallengeService:
 
   @Transactional
   def accept(challengeId: UUID, userId: UUID): Either[ChallengeError, Challenge] =
+    val result = acceptChallenge(challengeId, userId)
+    result.foreach(_ => meterRegistry.counter("nowchess.challenges.accepted").increment())
+    result
+
+  private def acceptChallenge(challengeId: UUID, userId: UUID): Either[ChallengeError, Challenge] =
     for
       challenge <- challengeRepository.findById(challengeId).toRight(ChallengeError.ChallengeNotFound)
       _         <- Either.cond(challenge.status == ChallengeStatus.Created, (), ChallengeError.ChallengeNotActive)
@@ -96,6 +114,11 @@ class ChallengeService:
 
   @Transactional
   def decline(challengeId: UUID, userId: UUID, req: DeclineRequest): Either[ChallengeError, Challenge] =
+    val result = declineChallenge(challengeId, userId, req)
+    result.foreach(_ => meterRegistry.counter("nowchess.challenges.declined").increment())
+    result
+
+  private def declineChallenge(challengeId: UUID, userId: UUID, req: DeclineRequest): Either[ChallengeError, Challenge] =
     for
       challenge <- challengeRepository.findById(challengeId).toRight(ChallengeError.ChallengeNotFound)
       _         <- Either.cond(challenge.status == ChallengeStatus.Created, (), ChallengeError.ChallengeNotActive)
@@ -109,6 +132,11 @@ class ChallengeService:
 
   @Transactional
   def cancel(challengeId: UUID, userId: UUID): Either[ChallengeError, Challenge] =
+    val result = cancelChallenge(challengeId, userId)
+    result.foreach(_ => meterRegistry.counter("nowchess.challenges.cancelled").increment())
+    result
+
+  private def cancelChallenge(challengeId: UUID, userId: UUID): Either[ChallengeError, Challenge] =
     for
       challenge <- challengeRepository.findById(challengeId).toRight(ChallengeError.ChallengeNotFound)
       _         <- Either.cond(challenge.status == ChallengeStatus.Created, (), ChallengeError.ChallengeNotActive)

modules/coordinator/src/main/scala/de/nowchess/coordinator/service/AutoScaler.scala

@@ -1,13 +1,16 @@
 package de.nowchess.coordinator.service
 
+import jakarta.annotation.PostConstruct
 import jakarta.enterprise.context.ApplicationScoped
 import jakarta.enterprise.inject.Instance
 import jakarta.inject.Inject
 import de.nowchess.coordinator.config.CoordinatorConfig
 import io.fabric8.kubernetes.api.model.GenericKubernetesResource
 import io.fabric8.kubernetes.client.KubernetesClient
+import io.micrometer.core.instrument.{Gauge, MeterRegistry}
 import org.jboss.logging.Logger
 
+import java.util.concurrent.atomic.AtomicReference
 import scala.compiletime.uninitialized
 
 @ApplicationScoped
@@ -21,10 +24,14 @@ class AutoScaler:
 
   @Inject
   private var instanceRegistry: InstanceRegistry = uninitialized
+
+  @Inject
+  private var meterRegistry: MeterRegistry = uninitialized
   // scalafix:on DisableSyntax.var
 
   private val log           = Logger.getLogger(classOf[AutoScaler])
   private val lastScaleTime = new java.util.concurrent.atomic.AtomicLong(0L)
+  private val avgLoadRef    = new AtomicReference[Double](0.0)
 
   private def kubeClientOpt: Option[KubernetesClient] =
     if kubeClientInstance.isUnsatisfied then None
@@ -33,6 +40,13 @@ class AutoScaler:
   private val argoApiVersion = "argoproj.io/v1alpha1"
   private val argoKind       = "Rollout"
 
+  @PostConstruct
+  def initMetrics(): Unit =
+    Gauge
+      .builder("nowchess.coordinator.load.average", avgLoadRef, _.get())
+      .register(meterRegistry)
+    ()
+
   // scalafix:off DisableSyntax.asInstanceOf
   private def rolloutSpec(rollout: GenericKubernetesResource): Option[java.util.Map[String, AnyRef]] =
     Option(rollout.get[AnyRef]("spec")).collect { case m: java.util.Map[?, ?] =>
@@ -48,6 +62,7 @@ class AutoScaler:
         val instances = instanceRegistry.getAllInstances.filter(_.state == "HEALTHY")
         if instances.nonEmpty then
           val avgLoad = instances.map(_.subscriptionCount).sum.toDouble / instances.size
+          avgLoadRef.set(avgLoad)
 
           if avgLoad > config.scaleUpThreshold * config.maxGamesPerCore then scaleUp()
           else if avgLoad < config.scaleDownThreshold * config.maxGamesPerCore then scaleDown()
@@ -79,6 +94,7 @@ class AutoScaler:
                       .inNamespace(config.k8sNamespace)
                       .resource(rollout)
                       .update()
+                    meterRegistry.counter("nowchess.coordinator.scale.events", "direction", "up").increment()
                     log.infof(
                       "Scaled up %s from %d to %d replicas",
                       config.k8sRolloutName,
@@ -91,6 +107,7 @@ class AutoScaler:
           }
         catch
           case ex: Exception =>
+            meterRegistry.counter("nowchess.coordinator.scale.failures", "direction", "up").increment()
             log.warnf(ex, "Failed to scale up %s", config.k8sRolloutName)
 
   def scaleDown(): Unit =
@@ -120,6 +137,7 @@ class AutoScaler:
                       .inNamespace(config.k8sNamespace)
                       .resource(rollout)
                       .update()
+                    meterRegistry.counter("nowchess.coordinator.scale.events", "direction", "down").increment()
                     log.infof(
                       "Scaled down %s from %d to %d replicas",
                       config.k8sRolloutName,
@@ -132,4 +150,5 @@ class AutoScaler:
           }
         catch
           case ex: Exception =>
+            meterRegistry.counter("nowchess.coordinator.scale.failures", "direction", "down").increment()
             log.warnf(ex, "Failed to scale down %s", config.k8sRolloutName)

modules/coordinator/src/main/scala/de/nowchess/coordinator/service/CacheEvictionManager.scala

@@ -5,6 +5,7 @@ import jakarta.inject.Inject
 import io.quarkus.redis.datasource.RedisDataSource
 import de.nowchess.coordinator.config.CoordinatorConfig
 import com.fasterxml.jackson.databind.ObjectMapper
+import io.micrometer.core.instrument.MeterRegistry
 import scala.jdk.CollectionConverters.*
 import org.jboss.logging.Logger
 import scala.compiletime.uninitialized
@@ -30,6 +31,9 @@ class CacheEvictionManager:
   @Inject
   private var objectMapper: ObjectMapper = uninitialized
 
+  @Inject
+  private var meterRegistry: MeterRegistry = uninitialized
+
   private val log         = Logger.getLogger(classOf[CacheEvictionManager])
   private var redisPrefix = "nowchess"
   // scalafix:on DisableSyntax.var
@@ -38,8 +42,12 @@ class CacheEvictionManager:
     redisPrefix = prefix
 
   def evictStaleGames: Unit =
-    log.info("Starting cache eviction scan")
+    meterRegistry.timer("nowchess.coordinator.cache.eviction.duration").record { () =>
+      runEviction()
+    }
 
+  private def runEviction(): Unit =
+    log.info("Starting cache eviction scan")
     val pattern         = s"$redisPrefix:game:entry:*"
     val keys            = redis.key(classOf[String]).keys(pattern)
     val now             = System.currentTimeMillis()
@@ -56,6 +64,7 @@ class CacheEvictionManager:
               try
                 coreGrpcClient.evictGames(instance.hostname, instance.grpcPort, List(gameId))
                 redis.key(classOf[String]).del(key)
+                meterRegistry.counter("nowchess.coordinator.cache.evictions").increment()
                 log.infof("Evicted idle game %s from %s", gameId, instance.instanceId)
                 count + 1
               catch

modules/coordinator/src/main/scala/de/nowchess/coordinator/service/HealthMonitor.scala

@@ -6,6 +6,7 @@ import jakarta.inject.Inject
 import de.nowchess.coordinator.config.CoordinatorConfig
 import io.fabric8.kubernetes.client.KubernetesClient
 import io.fabric8.kubernetes.api.model.Pod
+import io.micrometer.core.instrument.MeterRegistry
 import io.quarkus.redis.datasource.RedisDataSource
 import scala.jdk.CollectionConverters.*
 import org.jboss.logging.Logger
@@ -27,6 +28,9 @@ class HealthMonitor:
   @Inject
   private var redis: RedisDataSource = uninitialized
 
+  @Inject
+  private var meterRegistry: MeterRegistry = uninitialized
+
   private val log         = Logger.getLogger(classOf[HealthMonitor])
   private var redisPrefix = "nowchess"
   // scalafix:on DisableSyntax.var
@@ -39,6 +43,7 @@ class HealthMonitor:
     redisPrefix = prefix
 
   def checkInstanceHealth: Unit =
+    meterRegistry.counter("nowchess.coordinator.health.checks").increment()
     val evicted = instanceRegistry.evictStaleInstances(config.instanceDeadTimeout)
     if evicted.nonEmpty then log.warnf("Evicted %d stale instances: %s", evicted.size, evicted.mkString(", "))
     val instances = instanceRegistry.getAllInstances
@@ -108,6 +113,7 @@ class HealthMonitor:
               case Some(pod) =>
                 val isReady = isPodReady(pod)
                 if !isReady && inst.state == "HEALTHY" then
+                  meterRegistry.counter("nowchess.coordinator.pods.unhealthy").increment()
                   log.warnf("Pod %s not ready, marking instance %s dead", pod.getMetadata.getName, inst.instanceId)
                   instanceRegistry.markInstanceDead(inst.instanceId)
               case None =>

modules/coordinator/src/main/scala/de/nowchess/coordinator/service/InstanceRegistry.scala

@@ -1,5 +1,6 @@
 package de.nowchess.coordinator.service
 
+import jakarta.annotation.PostConstruct
 import jakarta.enterprise.context.ApplicationScoped
 import jakarta.inject.Inject
 import io.quarkus.redis.datasource.ReactiveRedisDataSource
@@ -9,6 +10,7 @@ import com.fasterxml.jackson.databind.ObjectMapper
 import de.nowchess.coordinator.dto.InstanceMetadata
 import java.util.concurrent.ConcurrentHashMap
 import java.time.{Duration, Instant}
+import io.micrometer.core.instrument.{Gauge, MeterRegistry}
 import io.smallrye.mutiny.Uni
 import org.jboss.logging.Logger
 
@@ -18,12 +20,22 @@ class InstanceRegistry:
   @Inject
   private var redis: ReactiveRedisDataSource = uninitialized
   private var redisPrefix                    = "nowchess"
+
+  @Inject
+  private var meterRegistry: MeterRegistry = uninitialized
   // scalafix:on DisableSyntax.var
 
   private val log       = Logger.getLogger(classOf[InstanceRegistry])
   private val mapper    = ObjectMapper()
   private val instances = ConcurrentHashMap[String, InstanceMetadata]()
 
+  @PostConstruct
+  def initMetrics(): Unit =
+    Gauge
+      .builder("nowchess.coordinator.instances.active", instances, m => m.size().toDouble)
+      .register(meterRegistry)
+    ()
+
   def setRedisPrefix(prefix: String): Unit =
     redisPrefix = prefix
 
@@ -45,6 +57,7 @@ class InstanceRegistry:
           val isNew    = !instances.containsKey(instanceId)
           instances.put(instanceId, metadata)
           if isNew then
+            meterRegistry.counter("nowchess.coordinator.instances.joined").increment()
             log.infof("Instance %s joined registry (subscriptions=%d)", instanceId, metadata.subscriptionCount)
           else
             log.debugf(
@@ -68,6 +81,7 @@ class InstanceRegistry:
 
   def removeInstance(instanceId: String): Unit =
     instances.remove(instanceId)
+    meterRegistry.counter("nowchess.coordinator.instances.removed").increment()
     log.infof("Instance %s removed from registry", instanceId)
 
   def evictStaleInstances(maxAge: Duration): List[String] =
@@ -83,6 +97,7 @@ class InstanceRegistry:
       .toList
     stale.foreach { id =>
       instances.remove(id)
+      meterRegistry.counter("nowchess.coordinator.instances.evicted").increment()
       log.warnf("Evicted stale instance %s (heartbeat older than %s)", id, maxAge)
     }
     stale

modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala

@@ -17,10 +17,12 @@ import de.nowchess.chess.observer.*
 import de.nowchess.api.error.GameError
 import de.nowchess.api.game.WinReason.{Checkmate, Resignation}
 import de.nowchess.api.io.{GameContextExport, GameContextImport}
-import de.nowchess.api.rules.RuleSet
+import de.nowchess.api.rules.{PostMoveStatus, RuleSet}
 
+import io.micrometer.core.instrument.{Counter, MeterRegistry, Timer}
 import java.time.Instant
 import java.util.concurrent.{Executors, ScheduledExecutorService, ScheduledFuture, TimeUnit}
+import java.util.concurrent.atomic.AtomicInteger
 
 /** Pure game engine that manages game state and notifies observers of state changes. All rule queries delegate to the
   * injected RuleSet. All user interactions go through Commands; state changes are broadcast via GameEvents.
@@ -33,6 +35,7 @@ class GameEngine(
     initialDrawOffer: Option[Color] = None,
     initialRedoStack: List[Move] = Nil,
     initialTakebackRequest: Option[Color] = None,
+    private val meterRegistry: Option[MeterRegistry] = None,
 ) extends Observable:
   // Ensure that initialBoard is set correctly for threefold repetition detection
   private val contextWithInitialBoard =
@@ -57,6 +60,17 @@ class GameEngine(
   @SuppressWarnings(Array("DisableSyntax.var"))
   private var pendingTakebackRequest: Option[Color] = initialTakebackRequest
 
+  meterRegistry.foreach { reg =>
+    GameEngine.activeGamesCount.incrementAndGet()
+    reg.counter("nowchess.games.started").increment()
+  }
+  private def gamesCompletedCounter(result: String): Counter =
+    meterRegistry.map(_.counter("nowchess.games.completed", "result", result)).orNull
+  private def movesProcessedCounter: Counter =
+    meterRegistry.map(_.counter("nowchess.moves.processed")).orNull
+  private def movesDurationTimer: Timer =
+    meterRegistry.map(_.timer("nowchess.moves.duration")).orNull
+
   // Start scheduler immediately for live clocks so passive expiry fires without waiting for a move.
   clockState.foreach(scheduleExpiryCheck)
 
@@ -165,6 +179,8 @@ class GameEngine(
       pendingTakebackRequest = None
       stopClock()
       redoStack = Nil
+      Option(gamesCompletedCounter("resignation")).foreach(_.increment())
+      GameEngine.activeGamesCount.decrementAndGet()
       notifyObservers(ResignEvent(currentContext, color))
   }
 
@@ -197,6 +213,8 @@ class GameEngine(
           pendingTakebackRequest = None
           stopClock()
           redoStack = Nil
+          Option(gamesCompletedCounter("draw.agreement")).foreach(_.increment())
+          GameEngine.activeGamesCount.decrementAndGet()
           notifyObservers(DrawEvent(currentContext, DrawReason.Agreement))
   }
 
@@ -223,11 +241,15 @@ class GameEngine(
       currentContext = currentContext.withResult(Some(GameResult.Draw(DrawReason.FiftyMoveRule)))
       stopClock()
       redoStack = Nil
+      Option(gamesCompletedCounter("draw.fifty_move")).foreach(_.increment())
+      GameEngine.activeGamesCount.decrementAndGet()
       notifyObservers(DrawEvent(currentContext, DrawReason.FiftyMoveRule))
     else if ruleSet.isThreefoldRepetition(currentContext) then
       currentContext = currentContext.withResult(Some(GameResult.Draw(DrawReason.ThreefoldRepetition)))
       stopClock()
       redoStack = Nil
+      Option(gamesCompletedCounter("draw.threefold")).foreach(_.increment())
+      GameEngine.activeGamesCount.decrementAndGet()
       notifyObservers(DrawEvent(currentContext, DrawReason.ThreefoldRepetition))
     else notifyObservers(InvalidMoveEvent(currentContext, InvalidMoveReason.DrawCannotBeClaimed))
   }
@@ -311,9 +333,18 @@ class GameEngine(
       currentContext = currentContext.withResult(Some(GameResult.Draw(reason)))
       stopClock()
       redoStack = Nil
+      Option(gamesCompletedCounter(drawReasonTag(reason))).foreach(_.increment())
+      GameEngine.activeGamesCount.decrementAndGet()
       notifyObservers(DrawEvent(currentContext, reason))
   }
 
+  private def drawReasonTag(reason: DrawReason): String = reason match
+    case DrawReason.Agreement            => "draw.agreement"
+    case DrawReason.FiftyMoveRule        => "draw.fifty_move"
+    case DrawReason.ThreefoldRepetition  => "draw.threefold"
+    case DrawReason.Stalemate            => "draw.stalemate"
+    case DrawReason.InsufficientMaterial => "draw.insufficient"
+
   /** Inject clock state directly (for testing). */
   private[engine] def injectClockState(cs: Option[ClockState]): Unit = synchronized { clockState = cs }
 
@@ -334,6 +365,11 @@ class GameEngine(
     pendingDrawOffer = None
     pendingTakebackRequest = None
     redoStack = Nil
+    val tag = result match
+      case GameResult.Draw(_) => "draw.insufficient"
+      case _                  => "timeout"
+    Option(gamesCompletedCounter(tag)).foreach(_.increment())
+    activeGamesCount.decrementAndGet()
     notifyObservers(TimeFlagEvent(currentContext, flagged))
 
   private def scheduleExpiryCheck(cs: ClockState): Unit =
@@ -369,6 +405,12 @@ class GameEngine(
   // ──── Private helpers ────
 
   private def executeMove(move: Move): Unit =
+    Option(movesDurationTimer) match
+      case Some(timer) => timer.record(() => executeMoveBody(move))
+      case None        => executeMoveBody(move)
+    Option(movesProcessedCounter).foreach(_.increment())
+
+  private def executeMoveBody(move: Move): Unit =
     if !isRedoing then
       redoStack = Nil
       pendingTakebackRequest = None
@@ -391,28 +433,36 @@ class GameEngine(
     )
 
     val status = ruleSet.postMoveStatus(currentContext)
-    if currentContext.result.isEmpty then
-      if status.isCheckmate then
-        val winner = currentContext.turn.opposite
-        currentContext = currentContext.withResult(Some(GameResult.Win(winner, Checkmate)))
-        cancelScheduled()
-        notifyObservers(CheckmateEvent(currentContext, winner))
-        redoStack = Nil
-      else if status.isStalemate then
-        currentContext = currentContext.withResult(Some(GameResult.Draw(DrawReason.Stalemate)))
-        cancelScheduled()
-        notifyObservers(DrawEvent(currentContext, DrawReason.Stalemate))
-        redoStack = Nil
-      else if status.isInsufficientMaterial then
-        currentContext = currentContext.withResult(Some(GameResult.Draw(DrawReason.InsufficientMaterial)))
-        cancelScheduled()
-        notifyObservers(DrawEvent(currentContext, DrawReason.InsufficientMaterial))
-        redoStack = Nil
-      else if status.isCheck then notifyObservers(CheckDetectedEvent(currentContext))
+    if currentContext.result.isEmpty then applyPostMoveStatus(status)
 
     if currentContext.halfMoveClock >= 100 then notifyObservers(FiftyMoveRuleAvailableEvent(currentContext))
     if status.isThreefoldRepetition then notifyObservers(ThreefoldRepetitionAvailableEvent(currentContext))
 
+  private def applyPostMoveStatus(status: PostMoveStatus): Unit =
+    if status.isCheckmate then
+      val winner = currentContext.turn.opposite
+      currentContext = currentContext.withResult(Some(GameResult.Win(winner, Checkmate)))
+      cancelScheduled()
+      Option(gamesCompletedCounter("checkmate")).foreach(_.increment())
+      GameEngine.activeGamesCount.decrementAndGet()
+      notifyObservers(CheckmateEvent(currentContext, winner))
+      redoStack = Nil
+    else if status.isStalemate then
+      currentContext = currentContext.withResult(Some(GameResult.Draw(DrawReason.Stalemate)))
+      cancelScheduled()
+      Option(gamesCompletedCounter("draw.stalemate")).foreach(_.increment())
+      GameEngine.activeGamesCount.decrementAndGet()
+      notifyObservers(DrawEvent(currentContext, DrawReason.Stalemate))
+      redoStack = Nil
+    else if status.isInsufficientMaterial then
+      currentContext = currentContext.withResult(Some(GameResult.Draw(DrawReason.InsufficientMaterial)))
+      cancelScheduled()
+      Option(gamesCompletedCounter("draw.insufficient")).foreach(_.increment())
+      GameEngine.activeGamesCount.decrementAndGet()
+      notifyObservers(DrawEvent(currentContext, DrawReason.InsufficientMaterial))
+      redoStack = Nil
+    else if status.isCheck then notifyObservers(CheckDetectedEvent(currentContext))
+
   private def translateMoveToNotation(move: Move, boardBefore: Board): String =
     move.moveType match
       case MoveType.CastleKingside    => "O-O"
@@ -526,3 +576,6 @@ class GameEngine(
           pendingTakebackRequest = None
           notifyObservers(TakebackDeclinedEvent(currentContext, color))
   }
+
+object GameEngine:
+  val activeGamesCount: AtomicInteger = new AtomicInteger(0)

modules/core/src/main/scala/de/nowchess/chess/registry/RedisGameRegistry.scala

@@ -12,7 +12,9 @@ import de.nowchess.chess.grpc.RuleSetGrpcAdapter
 import de.nowchess.chess.config.RedisConfig
 import de.nowchess.chess.grpc.IoGrpcClientWrapper
 import de.nowchess.chess.resource.GameDtoMapper
+import io.micrometer.core.instrument.{Gauge, MeterRegistry}
 import io.quarkus.redis.datasource.RedisDataSource
+import jakarta.annotation.PostConstruct
 import jakarta.enterprise.context.ApplicationScoped
 import jakarta.inject.Inject
 import org.eclipse.microprofile.rest.client.inject.RestClient
@@ -34,12 +36,20 @@ class RedisGameRegistry extends GameRegistry:
   @Inject var ioClient: IoGrpcClientWrapper               = uninitialized
   @Inject var ruleSetAdapter: RuleSetGrpcAdapter          = uninitialized
   @Inject @RestClient var storeClient: StoreServiceClient = uninitialized
+  @Inject var meterRegistry: MeterRegistry                = uninitialized
   // scalafix:on
 
   private val log          = Logger.getLogger(classOf[RedisGameRegistry])
   private val localEngines = ConcurrentHashMap[String, GameEntry]()
   private val rng          = new SecureRandom()
 
+  @PostConstruct
+  def initMetrics(): Unit =
+    Gauge
+      .builder("nowchess.games.active", GameEngine.activeGamesCount, _.get().toDouble)
+      .register(meterRegistry)
+    ()
+
   private def cacheKey(gameId: String) = s"${redisConfig.prefix}:game:entry:$gameId"
 
   def generateId(): String =
@@ -58,14 +68,17 @@ class RedisGameRegistry extends GameRegistry:
     )
 
   def get(gameId: String): Option[GameEntry] =
-    Option(localEngines.get(gameId)) match
+    val result = Option(localEngines.get(gameId)) match
       case Some(localEntry) =>
+        meterRegistry.counter("nowchess.games.cache.hits", "source", "local").increment()
         readRedisDto(gameId).flatMap(dto => Try(reconstruct(dto)).toOption) match
           case Some(redisEntry) if !sameSnapshot(localEntry, redisEntry) =>
             localEngines.put(gameId, redisEntry)
             Some(redisEntry)
           case _ => Some(localEntry)
       case None => fromRedis(gameId).orElse(fromDb(gameId))
+    if result.isEmpty then meterRegistry.counter("nowchess.games.cache.misses").increment()
+    result
 
   def update(entry: GameEntry): Unit =
     localEngines.put(entry.gameId, entry)
@@ -86,6 +99,7 @@ class RedisGameRegistry extends GameRegistry:
         }
       }
       .map { entry =>
+        meterRegistry.counter("nowchess.games.cache.hits", "source", "redis").increment()
         localEngines.put(gameId, entry)
         log.infof("Loaded game %s from Redis cache", gameId)
         entry
@@ -118,6 +132,7 @@ class RedisGameRegistry extends GameRegistry:
       (dto, reconstruct(dto))
     } match
       case scala.util.Success((dto, entry)) =>
+        meterRegistry.counter("nowchess.games.cache.hits", "source", "db").increment()
         log.infof("Loaded game %s from store service", gameId)
         localEngines.put(gameId, entry)
         redis.value(classOf[String]).setex(cacheKey(gameId), 1800L, objectMapper.writeValueAsString(dto))

modules/core/src/main/scala/de/nowchess/chess/service/InstanceHeartbeatService.scala

@@ -19,6 +19,8 @@ import de.nowchess.coordinator.proto.{CoordinatorServiceGrpc, *}
 import de.nowchess.coordinator.proto.CoordinatorServiceGrpc.CoordinatorServiceStub
 import io.grpc.stub.StreamObserver
 import io.grpc.Channel
+import io.micrometer.core.instrument.{Gauge, MeterRegistry}
+import java.util.concurrent.atomic.AtomicInteger
 
 @ApplicationScoped
 class InstanceHeartbeatService:
@@ -32,6 +34,9 @@ class InstanceHeartbeatService:
   @Inject
   private var mapper: ObjectMapper = uninitialized
 
+  @Inject
+  private var meterRegistry: MeterRegistry = uninitialized
+
   @GrpcClient("coordinator-grpc")
   private var channel: Channel = uninitialized
 
@@ -51,14 +56,15 @@ class InstanceHeartbeatService:
   private var streamObserver: Option[StreamObserver[HeartbeatFrame]] = None
   private var heartbeatExecutor                                      = Executors.newScheduledThreadPool(1)
   private var redisHeartbeatExecutor                                 = Executors.newScheduledThreadPool(1)
-  private var subscriptionCount                                      = 0
   private var localCacheSize                                         = 0
   private var serviceActive                                          = false
   private var shuttingDown                                           = false
   // scalafix:on DisableSyntax.var
   private val redisHeartbeatPending = new AtomicBoolean(false)
+  private val subscriptionCount     = new AtomicInteger(0)
 
   def onStart(@Observes event: StartupEvent): Unit =
+    Gauge.builder("nowchess.instance.subscriptions", subscriptionCount, _.get().toDouble).register(meterRegistry)
     if coordinatorEnabled then
       try
         shuttingDown = false
@@ -90,7 +96,7 @@ class InstanceHeartbeatService:
     redisPrefix = prefix
 
   def setSubscriptionCount(count: Int): Unit =
-    subscriptionCount = count
+    subscriptionCount.set(count)
 
   def setLocalCacheSize(count: Int): Unit =
     localCacheSize = count
@@ -99,13 +105,13 @@ class InstanceHeartbeatService:
     if coordinatorEnabled then
       val setKey = s"$redisPrefix:instance:$instanceId:games"
       redis.set(classOf[String]).sadd(setKey, gameId)
-      subscriptionCount += 1
+      subscriptionCount.incrementAndGet()
 
   def removeGameSubscription(gameId: String): Unit =
     if coordinatorEnabled then
       val setKey = s"$redisPrefix:instance:$instanceId:games"
       redis.set(classOf[String]).srem(setKey, gameId)
-      subscriptionCount = Math.max(0, subscriptionCount - 1)
+      subscriptionCount.updateAndGet(c => Math.max(0, c - 1))
 
   private def generateInstanceId(): Unit =
     val hostname =
@@ -162,13 +168,14 @@ class InstanceHeartbeatService:
           .setHostname(getHostname)
           .setHttpPort(httpPort)
           .setGrpcPort(grpcPort)
-          .setSubscriptionCount(subscriptionCount)
+          .setSubscriptionCount(subscriptionCount.get())
           .setLocalCacheSize(localCacheSize)
           .setTimestampMillis(System.currentTimeMillis())
           .build()
         observer.onNext(frame)
       catch
         case ex: Exception =>
+          meterRegistry.counter("nowchess.heartbeat.failures").increment()
           log.warnf(ex, "Failed to send heartbeat frame")
     }
 
@@ -182,7 +189,7 @@ class InstanceHeartbeatService:
           "hostname"          -> getHostname,
           "httpPort"          -> httpPort,
           "grpcPort"          -> grpcPort,
-          "subscriptionCount" -> subscriptionCount,
+          "subscriptionCount" -> subscriptionCount.get(),
           "localCacheSize"    -> localCacheSize,
           "lastHeartbeat"     -> java.time.Instant.now().toString,
           "state"             -> "HEALTHY",

modules/official-bots/src/main/scala/de/nowchess/bot/logic/AlphaBetaSearch.scala

@@ -7,6 +7,7 @@ import de.nowchess.bot.ai.Evaluation
 import de.nowchess.bot.util.ZobristHash
 import de.nowchess.api.rules.RuleSet
 import de.nowchess.rules.sets.DefaultRules
+import io.micrometer.core.instrument.MeterRegistry
 import java.util.concurrent.atomic.{AtomicInteger, AtomicLong}
 
 final class AlphaBetaSearch(
@@ -14,6 +15,7 @@ final class AlphaBetaSearch(
     tt: TranspositionTable = TranspositionTable(),
     weights: Evaluation,
     numThreads: Int = Runtime.getRuntime.availableProcessors,
+    meterRegistry: MeterRegistry = null,
 ):
 
   private val INF                  = Int.MaxValue / 2
@@ -85,8 +87,8 @@ final class AlphaBetaSearch(
     val rootHash = ZobristHash.hash(context)
 
     @scala.annotation.tailrec
-    def loop(bestSoFar: Option[Move], prevScore: Int, depth: Int): Option[Move] =
-      if isOutOfTime then bestSoFar
+    def loop(bestSoFar: Option[Move], prevScore: Int, depth: Int, lastDepth: Int): (Option[Move], Int) =
+      if isOutOfTime then (bestSoFar, lastDepth)
       else
         val (alpha, beta) =
           if depth == 1 then (-INF, INF) else (prevScore - ASPIRATION_DELTA, prevScore + ASPIRATION_DELTA)
@@ -99,9 +101,16 @@ final class AlphaBetaSearch(
           rootHash,
           excludedRootMoves,
         )
-        loop(move.orElse(bestSoFar), score, depth + 1)
+        loop(move.orElse(bestSoFar), score, depth + 1, depth)
 
-    loop(None, 0, 1)
+    val (result, depthReached) = loop(None, 0, 1, 0)
+    recordSearchMetrics(depthReached)
+    result
+
+  private def recordSearchMetrics(depthReached: Int): Unit =
+    if meterRegistry != null then
+      meterRegistry.summary("nowchess.bot.search.nodes").record(nodeCount.get().toDouble)
+      meterRegistry.summary("nowchess.bot.search.depth").record(depthReached.toDouble)
 
   private def isOutOfTime: Boolean =
     System.currentTimeMillis - timeStartMs.get >= timeLimitMs.get

modules/official-bots/src/main/scala/de/nowchess/bot/service/OfficialBotService.scala

@@ -6,6 +6,7 @@ import de.nowchess.bot.BotController
 import de.nowchess.bot.BotDifficulty
 import de.nowchess.bot.config.RedisConfig
 import de.nowchess.io.fen.FenParser
+import io.micrometer.core.instrument.MeterRegistry
 import io.quarkus.redis.datasource.RedisDataSource
 import io.quarkus.runtime.StartupEvent
 import jakarta.enterprise.context.ApplicationScoped
@@ -18,10 +19,11 @@ import java.util.function.Consumer
 class OfficialBotService:
 
   // scalafix:off DisableSyntax.var
-  @Inject var redis: RedisDataSource       = uninitialized
-  @Inject var redisConfig: RedisConfig     = uninitialized
-  @Inject var objectMapper: ObjectMapper   = uninitialized
-  @Inject var botController: BotController = uninitialized
+  @Inject var redis: RedisDataSource         = uninitialized
+  @Inject var redisConfig: RedisConfig       = uninitialized
+  @Inject var objectMapper: ObjectMapper     = uninitialized
+  @Inject var botController: BotController   = uninitialized
+  @Inject var meterRegistry: MeterRegistry   = uninitialized
   // scalafix:on DisableSyntax.var
 
   private val terminalStatuses =
@@ -85,7 +87,10 @@ class OfficialBotService:
     val level = DifficultyMapper.fromElo(difficulty).getOrElse(BotDifficulty.Medium)
     botController.getBot(botName).orElse(botController.getBot(level.toString.toLowerCase)).foreach { bot =>
       FenParser.parseFen(fen).toOption.foreach { context =>
-        bot(context).foreach { move =>
+        val timer   = meterRegistry.timer("nowchess.bot.move.duration", "bot", botName)
+        val moveOpt = timer.recordCallable(() => bot(context))
+        moveOpt.flatten.foreach { move =>
+          meterRegistry.counter("nowchess.bot.moves.computed", "bot", botName).increment()
           val uci      = toUci(move)
           val c2sTopic = s"${redisConfig.prefix}:game:$gameId:c2s"
           val moveMsg  = s"""{"type":"MOVE","uci":"$uci","playerId":"$botAccountId"}"""

modules/store/src/main/scala/de/nowchess/store/service/GameWritebackService.scala

@@ -3,6 +3,7 @@ package de.nowchess.store.service
 import de.nowchess.api.dto.GameWritebackEventDto
 import de.nowchess.store.domain.GameRecord
 import de.nowchess.store.repository.GameRecordRepository
+import io.micrometer.core.instrument.{Counter, MeterRegistry, Timer}
 import jakarta.enterprise.context.ApplicationScoped
 import jakarta.inject.Inject
 import jakarta.transaction.Transactional
@@ -12,64 +13,84 @@ import java.time.Instant
 
 @ApplicationScoped
 class GameWritebackService:
-  @Inject
+
   // scalafix:off DisableSyntax.var
+  @Inject
   var repository: GameRecordRepository = uninitialized
-  // scalafix:on
+
+  @Inject
+  var meterRegistry: MeterRegistry = uninitialized
+  // scalafix:on DisableSyntax.var
+
+  private lazy val writebackTimer: Timer =
+    meterRegistry.timer("nowchess.store.writeback.duration")
+
+  private lazy val writebackSkipped: Counter =
+    meterRegistry.counter("nowchess.store.writeback.skipped")
+
+  private def gamesWrittenCounter(operation: String): Counter =
+    meterRegistry.counter("nowchess.store.games.written", "operation", operation)
 
   @Transactional
   def writeBack(event: GameWritebackEventDto): Unit =
+    writebackTimer.record(() => doWriteBack(event))
+
+  private def doWriteBack(event: GameWritebackEventDto): Unit =
     repository.findByGameId(event.gameId) match
       case None =>
-        val record = new GameRecord
-        record.gameId = event.gameId
-        record.fen = event.fen
-        record.pgn = event.pgn
-        record.moveCount = event.moveCount
-        record.whiteId = event.whiteId
-        record.whiteName = event.whiteName
-        record.blackId = event.blackId
-        record.blackName = event.blackName
-        record.mode = event.mode
-        record.resigned = event.resigned
-        record.limitSeconds = event.limitSeconds.map(java.lang.Integer.valueOf).orNull
-        record.incrementSeconds = event.incrementSeconds.map(java.lang.Integer.valueOf).orNull
-        record.daysPerMove = event.daysPerMove.map(java.lang.Integer.valueOf).orNull
-        record.whiteRemainingMs = event.whiteRemainingMs.map(java.lang.Long.valueOf).orNull
-        record.blackRemainingMs = event.blackRemainingMs.map(java.lang.Long.valueOf).orNull
-        record.incrementMs = event.incrementMs.map(java.lang.Long.valueOf).orNull
-        record.clockLastTickAt = event.clockLastTickAt.map(java.lang.Long.valueOf).orNull
-        record.clockMoveDeadline = event.clockMoveDeadline.map(java.lang.Long.valueOf).orNull
-        record.clockActiveColor = event.clockActiveColor.orNull
-        record.pendingDrawOffer = event.pendingDrawOffer.orNull
-        record.result = event.result.orNull
-        record.terminationReason = event.terminationReason.orNull
-        record.createdAt = Instant.now()
-        record.updatedAt = Instant.now()
-        repository.persist(record)
+        createRecord(event)
+        gamesWrittenCounter("create").increment()
       case Some(r) if event.moveCount > r.moveCount || event.pgn != r.pgn =>
-        r.fen = event.fen
-        r.pgn = event.pgn
-        r.moveCount = event.moveCount
-        r.whiteId = event.whiteId
-        r.whiteName = event.whiteName
-        r.blackId = event.blackId
-        r.blackName = event.blackName
-        r.mode = event.mode
-        r.resigned = event.resigned
-        r.limitSeconds = event.limitSeconds.map(java.lang.Integer.valueOf).orNull
-        r.incrementSeconds = event.incrementSeconds.map(java.lang.Integer.valueOf).orNull
-        r.daysPerMove = event.daysPerMove.map(java.lang.Integer.valueOf).orNull
-        r.whiteRemainingMs = event.whiteRemainingMs.map(java.lang.Long.valueOf).orNull
-        r.blackRemainingMs = event.blackRemainingMs.map(java.lang.Long.valueOf).orNull
-        r.incrementMs = event.incrementMs.map(java.lang.Long.valueOf).orNull
-        r.clockLastTickAt = event.clockLastTickAt.map(java.lang.Long.valueOf).orNull
-        r.clockMoveDeadline = event.clockMoveDeadline.map(java.lang.Long.valueOf).orNull
-        r.clockActiveColor = event.clockActiveColor.orNull
-        r.pendingDrawOffer = event.pendingDrawOffer.orNull
-        r.pendingTakebackOffer = event.pendingTakebackRequest.orNull
-        r.result = event.result.orNull
-        r.terminationReason = event.terminationReason.orNull
-        r.updatedAt = Instant.now()
-        repository.merge(r)
-      case _ => ()
+        updateRecord(r, event)
+        gamesWrittenCounter("update").increment()
+      case _ =>
+        writebackSkipped.increment()
+
+  private def createRecord(event: GameWritebackEventDto): Unit =
+    val record = new GameRecord
+    record.gameId = event.gameId
+    record.fen = event.fen
+    record.pgn = event.pgn
+    record.moveCount = event.moveCount
+    record.whiteId = event.whiteId
+    record.whiteName = event.whiteName
+    record.blackId = event.blackId
+    record.blackName = event.blackName
+    record.mode = event.mode
+    record.resigned = event.resigned
+    applyClockFields(record, event)
+    record.result = event.result.orNull
+    record.terminationReason = event.terminationReason.orNull
+    record.createdAt = Instant.now()
+    record.updatedAt = Instant.now()
+    repository.persist(record)
+
+  private def updateRecord(r: GameRecord, event: GameWritebackEventDto): Unit =
+    r.fen = event.fen
+    r.pgn = event.pgn
+    r.moveCount = event.moveCount
+    r.whiteId = event.whiteId
+    r.whiteName = event.whiteName
+    r.blackId = event.blackId
+    r.blackName = event.blackName
+    r.mode = event.mode
+    r.resigned = event.resigned
+    applyClockFields(r, event)
+    r.pendingDrawOffer = event.pendingDrawOffer.orNull
+    r.pendingTakebackOffer = event.pendingTakebackRequest.orNull
+    r.result = event.result.orNull
+    r.terminationReason = event.terminationReason.orNull
+    r.updatedAt = Instant.now()
+    repository.merge(r)
+
+  private def applyClockFields(r: GameRecord, event: GameWritebackEventDto): Unit =
+    r.limitSeconds = event.limitSeconds.map(java.lang.Integer.valueOf).orNull
+    r.incrementSeconds = event.incrementSeconds.map(java.lang.Integer.valueOf).orNull
+    r.daysPerMove = event.daysPerMove.map(java.lang.Integer.valueOf).orNull
+    r.whiteRemainingMs = event.whiteRemainingMs.map(java.lang.Long.valueOf).orNull
+    r.blackRemainingMs = event.blackRemainingMs.map(java.lang.Long.valueOf).orNull
+    r.incrementMs = event.incrementMs.map(java.lang.Long.valueOf).orNull
+    r.clockLastTickAt = event.clockLastTickAt.map(java.lang.Long.valueOf).orNull
+    r.clockMoveDeadline = event.clockMoveDeadline.map(java.lang.Long.valueOf).orNull
+    r.clockActiveColor = event.clockActiveColor.orNull
+    r.pendingDrawOffer = event.pendingDrawOffer.orNull

modules/ws/src/main/scala/de/nowchess/ws/resource/GameWebSocketResource.scala

@@ -1,6 +1,7 @@
 package de.nowchess.ws.resource
 
 import de.nowchess.ws.config.RedisConfig
+import io.micrometer.core.instrument.{Counter, Gauge, MeterRegistry}
 import io.quarkus.redis.datasource.RedisDataSource
 import io.quarkus.redis.datasource.pubsub.PubSubCommands
 import io.quarkus.websockets.next.*
@@ -26,10 +27,27 @@ class GameWebSocketResource:
 
   @Inject
   var jwtParser: JWTParser = uninitialized
+
+  @Inject
+  var meterRegistry: MeterRegistry = uninitialized
   // scalafix:on DisableSyntax.var
 
   private val connections = new ConcurrentHashMap[String, ConnectionMeta]()
 
+  private lazy val connectionsOpened: Counter =
+    meterRegistry.counter("nowchess.ws.connections.opened")
+
+  private lazy val connectionsClosed: Counter =
+    meterRegistry.counter("nowchess.ws.connections.closed")
+
+  private lazy val messagesReceived: Counter =
+    meterRegistry.counter("nowchess.ws.messages.received")
+
+  private lazy val activeGauge: Unit =
+    Gauge
+      .builder("nowchess.ws.connections.active", connections, _.size().toDouble)
+      .register(meterRegistry)
+
   private def s2cTopic(gameId: String): String =
     s"${redisConfig.prefix}:game:$gameId:s2c"
 
@@ -38,22 +56,19 @@ class GameWebSocketResource:
 
   @OnOpen
   def onOpen(connection: WebSocketConnection, handshake: HandshakeRequest): Unit =
-    val gameId = connection.pathParam("gameId")
-    val playerId = Option(handshake.header("Authorization"))
-      .filter(_.nonEmpty)
-      .flatMap(token => Try(jwtParser.parse(token)).toOption)
-      .map(_.getSubject)
+    activeGauge
+    val gameId   = connection.pathParam("gameId")
+    val playerId = resolvePlayerId(handshake)
     log.infof("Game WebSocket opened — gameId=%s playerId=%s", gameId, playerId.getOrElse("anonymous"))
     val handler: Consumer[String] = msg => connection.sendText(msg).subscribe().`with`(_ => (), _ => ())
     val subscriber                = redis.pubsub(classOf[String]).subscribe(s2cTopic(gameId), handler)
     connections.put(connection.id(), ConnectionMeta(gameId, subscriber, playerId))
-    val connectedMsg = playerId match
-      case Some(pid) => s"""{"type":"CONNECTED","gameId":"$gameId","playerId":"$pid"}"""
-      case None      => s"""{"type":"CONNECTED","gameId":"$gameId"}"""
-    redis.pubsub(classOf[String]).publish(c2sTopic(gameId), connectedMsg)
+    connectionsOpened.increment()
+    publishConnected(gameId, playerId)
 
   @OnTextMessage
   def onTextMessage(connection: WebSocketConnection, message: String): Unit =
+    messagesReceived.increment()
     Option(connections.get(connection.id())).foreach { meta =>
       val enriched = meta.playerId match
         case Some(pid) => injectPlayerId(message, pid)
@@ -66,8 +81,21 @@ class GameWebSocketResource:
     Option(connections.remove(connection.id())).foreach { meta =>
       log.infof("Game WebSocket closed — gameId=%s", meta.gameId)
       meta.subscriber.unsubscribe(s2cTopic(meta.gameId))
+      connectionsClosed.increment()
     }
 
+  private def resolvePlayerId(handshake: HandshakeRequest): Option[String] =
+    Option(handshake.header("Authorization"))
+      .filter(_.nonEmpty)
+      .flatMap(token => Try(jwtParser.parse(token)).toOption)
+      .map(_.getSubject)
+
+  private def publishConnected(gameId: String, playerId: Option[String]): Unit =
+    val connectedMsg = playerId match
+      case Some(pid) => s"""{"type":"CONNECTED","gameId":"$gameId","playerId":"$pid"}"""
+      case None      => s"""{"type":"CONNECTED","gameId":"$gameId"}"""
+    redis.pubsub(classOf[String]).publish(c2sTopic(gameId), connectedMsg)
+
   private def injectPlayerId(msg: String, pid: String): String =
     val trimmed = msg.trim
     if trimmed.endsWith("}") then trimmed.dropRight(1) + s""","playerId":"$pid"}"""