feat(logging): add DEBUG/INFO/WARN logging across services (NCS-72) (#41)

Reviewed-on: #41
Co-authored-by: Janis <janis.e.20@gmx.de>
Co-committed-by: Janis <janis.e.20@gmx.de>

modules/core/src/main/scala/de/nowchess/chess/grpc/CoordinatorServiceHandler.scala

@@ -7,11 +7,15 @@ import scala.compiletime.uninitialized
 import de.nowchess.coordinator.proto.{CoordinatorServiceGrpc, *}
 import de.nowchess.chess.redis.GameRedisSubscriberManager
 import io.grpc.stub.StreamObserver
+import org.jboss.logging.Logger
 import scala.jdk.CollectionConverters.*
 
 @GrpcService
 @Singleton
 class CoordinatorServiceHandler extends CoordinatorServiceGrpc.CoordinatorServiceImplBase:
+
+  private val log = Logger.getLogger(classOf[CoordinatorServiceHandler])
+
   // scalafix:off DisableSyntax.var
   @Inject
   private var gameSubscriberManager: GameRedisSubscriberManager = uninitialized
@@ -22,6 +26,7 @@ class CoordinatorServiceHandler extends CoordinatorServiceGrpc.CoordinatorServic
       responseObserver: StreamObserver[BatchResubscribeResponse],
   ): Unit =
     val count = gameSubscriberManager.batchResubscribeGames(request.getGameIdsList)
+    log.infof("Coordinator: batch resubscribe %d games → subscribed %d", request.getGameIdsList.size(), count)
     val response = BatchResubscribeResponse
       .newBuilder()
       .setSubscribedCount(count)
@@ -34,6 +39,7 @@ class CoordinatorServiceHandler extends CoordinatorServiceGrpc.CoordinatorServic
       responseObserver: StreamObserver[UnsubscribeGamesResponse],
   ): Unit =
     val count = gameSubscriberManager.unsubscribeGames(request.getGameIdsList)
+    log.infof("Coordinator: unsubscribe %d games → unsubscribed %d", request.getGameIdsList.size(), count)
     val response = UnsubscribeGamesResponse
       .newBuilder()
       .setUnsubscribedCount(count)
@@ -46,6 +52,7 @@ class CoordinatorServiceHandler extends CoordinatorServiceGrpc.CoordinatorServic
       responseObserver: StreamObserver[EvictGamesResponse],
   ): Unit =
     val count = gameSubscriberManager.evictGames(request.getGameIdsList)
+    log.infof("Coordinator: evict %d games → evicted %d", request.getGameIdsList.size(), count)
     val response = EvictGamesResponse
       .newBuilder()
       .setEvictedCount(count)
@@ -58,6 +65,7 @@ class CoordinatorServiceHandler extends CoordinatorServiceGrpc.CoordinatorServic
       responseObserver: StreamObserver[DrainInstanceResponse],
   ): Unit =
     val migrated = gameSubscriberManager.drainInstance()
+    log.infof("Coordinator: drain instance → migrated %d games", migrated)
     val response = DrainInstanceResponse
       .newBuilder()
       .setGamesMigrated(migrated)

modules/core/src/main/scala/de/nowchess/chess/grpc/IoGrpcClientWrapper.scala

@@ -5,29 +5,63 @@ import de.nowchess.chess.client.CombinedExportResponse
 import de.nowchess.core.proto.*
 import io.quarkus.grpc.GrpcClient
 import jakarta.enterprise.context.ApplicationScoped
+import org.jboss.logging.Logger
 
 import scala.compiletime.uninitialized
 
 @ApplicationScoped
 class IoGrpcClientWrapper:
 
+  private val log = Logger.getLogger(classOf[IoGrpcClientWrapper])
+
   // scalafix:off DisableSyntax.var
   @GrpcClient("io-grpc")
   var stub: IoServiceGrpc.IoServiceBlockingStub = uninitialized
   // scalafix:on DisableSyntax.var
 
   def exportCombined(ctx: GameContext): CombinedExportResponse =
-    val combined = stub.exportCombined(CoreProtoMapper.toProtoGameContext(ctx))
-    CombinedExportResponse(combined.getFen, combined.getPgn)
+    try
+      val combined = stub.exportCombined(CoreProtoMapper.toProtoGameContext(ctx))
+      CombinedExportResponse(combined.getFen, combined.getPgn)
+    catch
+      case ex: Exception =>
+        log.warnf(ex, "IO gRPC exportCombined failed")
+        // scalafix:off DisableSyntax.throw
+        throw ex
+      // scalafix:on DisableSyntax.throw
 
   def importFen(fen: String): GameContext =
-    CoreProtoMapper.fromProtoGameContext(stub.importFen(ProtoImportFenRequest.newBuilder().setFen(fen).build()))
+    try CoreProtoMapper.fromProtoGameContext(stub.importFen(ProtoImportFenRequest.newBuilder().setFen(fen).build()))
+    catch
+      case ex: Exception =>
+        log.warnf(ex, "IO gRPC importFen failed for fen %s", fen)
+        // scalafix:off DisableSyntax.throw
+        throw ex
+      // scalafix:on DisableSyntax.throw
 
   def importPgn(pgn: String): GameContext =
-    CoreProtoMapper.fromProtoGameContext(stub.importPgn(ProtoImportPgnRequest.newBuilder().setPgn(pgn).build()))
+    try CoreProtoMapper.fromProtoGameContext(stub.importPgn(ProtoImportPgnRequest.newBuilder().setPgn(pgn).build()))
+    catch
+      case ex: Exception =>
+        log.warnf(ex, "IO gRPC importPgn failed")
+        // scalafix:off DisableSyntax.throw
+        throw ex
+      // scalafix:on DisableSyntax.throw
 
   def exportFen(ctx: GameContext): String =
-    stub.exportFen(CoreProtoMapper.toProtoGameContext(ctx)).getValue
+    try stub.exportFen(CoreProtoMapper.toProtoGameContext(ctx)).getValue
+    catch
+      case ex: Exception =>
+        log.warnf(ex, "IO gRPC exportFen failed")
+        // scalafix:off DisableSyntax.throw
+        throw ex
+      // scalafix:on DisableSyntax.throw
 
   def exportPgn(ctx: GameContext): String =
-    stub.exportPgn(CoreProtoMapper.toProtoGameContext(ctx)).getValue
+    try stub.exportPgn(CoreProtoMapper.toProtoGameContext(ctx)).getValue
+    catch
+      case ex: Exception =>
+        log.warnf(ex, "IO gRPC exportPgn failed")
+        // scalafix:off DisableSyntax.throw
+        throw ex
+      // scalafix:on DisableSyntax.throw

modules/core/src/main/scala/de/nowchess/chess/grpc/RuleSetGrpcAdapter.scala

@@ -7,6 +7,7 @@ import de.nowchess.api.rules.{PostMoveStatus, RuleSet}
 import de.nowchess.core.proto.*
 import io.quarkus.grpc.GrpcClient
 import jakarta.enterprise.context.ApplicationScoped
+import org.jboss.logging.Logger
 
 import scala.compiletime.uninitialized
 import scala.jdk.CollectionConverters.*
@@ -14,28 +15,59 @@ import scala.jdk.CollectionConverters.*
 @ApplicationScoped
 class RuleSetGrpcAdapter extends RuleSet:
 
+  private val log = Logger.getLogger(classOf[RuleSetGrpcAdapter])
+
   // scalafix:off DisableSyntax.var
   @GrpcClient("rule-grpc")
   var stub: RuleServiceGrpc.RuleServiceBlockingStub = uninitialized
   // scalafix:on DisableSyntax.var
 
   def candidateMoves(ctx: GameContext)(sq: Square): List[Move] =
-    val req =
-      ProtoSquareRequest.newBuilder().setContext(CoreProtoMapper.toProtoGameContext(ctx)).setSquare(sq.toString).build()
-    stub.candidateMoves(req).getMovesList.asScala.flatMap(CoreProtoMapper.fromProtoMove).toList
+    try
+      val req =
+        ProtoSquareRequest
+          .newBuilder()
+          .setContext(CoreProtoMapper.toProtoGameContext(ctx))
+          .setSquare(sq.toString)
+          .build()
+      stub.candidateMoves(req).getMovesList.asScala.flatMap(CoreProtoMapper.fromProtoMove).toList
+    catch
+      case ex: Exception =>
+        log.warnf(ex, "Rule gRPC candidateMoves failed")
+        // scalafix:off DisableSyntax.throw
+        throw ex
+      // scalafix:on DisableSyntax.throw
 
   def legalMoves(ctx: GameContext)(sq: Square): List[Move] =
-    val req =
-      ProtoSquareRequest.newBuilder().setContext(CoreProtoMapper.toProtoGameContext(ctx)).setSquare(sq.toString).build()
-    stub.legalMoves(req).getMovesList.asScala.flatMap(CoreProtoMapper.fromProtoMove).toList
+    try
+      val req =
+        ProtoSquareRequest
+          .newBuilder()
+          .setContext(CoreProtoMapper.toProtoGameContext(ctx))
+          .setSquare(sq.toString)
+          .build()
+      stub.legalMoves(req).getMovesList.asScala.flatMap(CoreProtoMapper.fromProtoMove).toList
+    catch
+      case ex: Exception =>
+        log.warnf(ex, "Rule gRPC legalMoves failed")
+        // scalafix:off DisableSyntax.throw
+        throw ex
+      // scalafix:on DisableSyntax.throw
 
   def allLegalMoves(ctx: GameContext): List[Move] =
-    stub
-      .allLegalMoves(CoreProtoMapper.toProtoGameContext(ctx))
-      .getMovesList
-      .asScala
-      .flatMap(CoreProtoMapper.fromProtoMove)
-      .toList
+    try
+      stub
+        .allLegalMoves(CoreProtoMapper.toProtoGameContext(ctx))
+        .getMovesList
+        .asScala
+        .flatMap(CoreProtoMapper.fromProtoMove)
+        .toList
+    catch
+      case ex: Exception =>
+        log.warnf(ex, "Rule gRPC allLegalMoves failed")
+        // scalafix:off DisableSyntax.throw
+        throw ex
+      // scalafix:on DisableSyntax.throw
 
   def isCheck(ctx: GameContext): Boolean =
     stub.isCheck(CoreProtoMapper.toProtoGameContext(ctx)).getValue
@@ -56,19 +88,33 @@ class RuleSetGrpcAdapter extends RuleSet:
     stub.isThreefoldRepetition(CoreProtoMapper.toProtoGameContext(ctx)).getValue
 
   def applyMove(ctx: GameContext)(move: Move): GameContext =
-    val req = ProtoMoveRequest
-      .newBuilder()
-      .setContext(CoreProtoMapper.toProtoGameContext(ctx))
-      .setMove(CoreProtoMapper.toProtoMove(move))
-      .build()
-    CoreProtoMapper.fromProtoGameContext(stub.applyMove(req))
+    try
+      val req = ProtoMoveRequest
+        .newBuilder()
+        .setContext(CoreProtoMapper.toProtoGameContext(ctx))
+        .setMove(CoreProtoMapper.toProtoMove(move))
+        .build()
+      CoreProtoMapper.fromProtoGameContext(stub.applyMove(req))
+    catch
+      case ex: Exception =>
+        log.warnf(ex, "Rule gRPC applyMove failed")
+        // scalafix:off DisableSyntax.throw
+        throw ex
+      // scalafix:on DisableSyntax.throw
 
   override def postMoveStatus(ctx: GameContext): PostMoveStatus =
-    val p = stub.postMoveStatus(CoreProtoMapper.toProtoGameContext(ctx))
-    PostMoveStatus(
-      p.getIsCheckmate,
-      p.getIsStalemate,
-      p.getIsInsufficientMaterial,
-      p.getIsCheck,
-      p.getIsThreefoldRepetition,
-    )
+    try
+      val p = stub.postMoveStatus(CoreProtoMapper.toProtoGameContext(ctx))
+      PostMoveStatus(
+        p.getIsCheckmate,
+        p.getIsStalemate,
+        p.getIsInsufficientMaterial,
+        p.getIsCheck,
+        p.getIsThreefoldRepetition,
+      )
+    catch
+      case ex: Exception =>
+        log.warnf(ex, "Rule gRPC postMoveStatus failed")
+        // scalafix:off DisableSyntax.throw
+        throw ex
+      // scalafix:on DisableSyntax.throw

modules/core/src/main/scala/de/nowchess/chess/redis/GameRedisPublisher.scala

@@ -10,6 +10,10 @@ import de.nowchess.chess.observer.{GameEvent, Observer}
 import de.nowchess.chess.registry.GameRegistry
 import de.nowchess.chess.resource.GameDtoMapper
 import io.quarkus.redis.datasource.RedisDataSource
+import org.jboss.logging.Logger
+
+object GameRedisPublisher:
+  private val log = Logger.getLogger(classOf[GameRedisPublisher])
 
 class GameRedisPublisher(
     gameId: String,
@@ -23,57 +27,60 @@ class GameRedisPublisher(
 ) extends Observer:
 
   def onGameEvent(event: GameEvent): Unit =
-    registry.get(gameId).foreach { entry =>
-      val dto  = GameDtoMapper.toGameStateDto(entry, ioClient)
-      val json = objectMapper.writeValueAsString(GameStateEventDto(dto))
-      redis.pubsub(classOf[String]).publish(s2cTopicName, json)
+    try
+      GameRedisPublisher.log.debugf("Publishing game event for game %s", gameId)
+      registry.get(gameId).foreach { entry =>
+        val dto  = GameDtoMapper.toGameStateDto(entry, ioClient)
+        val json = objectMapper.writeValueAsString(GameStateEventDto(dto))
+        redis.pubsub(classOf[String]).publish(s2cTopicName, json)
 
-      val clock = entry.engine.currentClockState
-      val wb = GameWritebackEventDto(
-        gameId = gameId,
-        fen = dto.fen,
-        pgn = dto.pgn,
-        moveCount = entry.engine.context.moves.size,
-        whiteId = entry.white.id.value,
-        whiteName = entry.white.displayName,
-        blackId = entry.black.id.value,
-        blackName = entry.black.displayName,
-        mode = entry.mode.toString,
-        resigned = entry.resigned,
-        limitSeconds = entry.engine.timeControl match {
-          case de.nowchess.api.game.TimeControl.Clock(l, _) => Some(l); case _ => None
-        },
-        incrementSeconds = entry.engine.timeControl match {
-          case de.nowchess.api.game.TimeControl.Clock(_, i) => Some(i); case _ => None
-        },
-        daysPerMove = entry.engine.timeControl match {
-          case de.nowchess.api.game.TimeControl.Correspondence(d) => Some(d); case _ => None
-        },
-        whiteRemainingMs = clock.collect { case c: LiveClockState => c.whiteRemainingMs },
-        blackRemainingMs = clock.collect { case c: LiveClockState => c.blackRemainingMs },
-        incrementMs = clock.collect { case c: LiveClockState => c.incrementMs },
-        clockLastTickAt = clock.collect { case c: LiveClockState => c.lastTickAt.toEpochMilli },
-        clockMoveDeadline = clock.collect { case c: CorrespondenceClockState => c.moveDeadline.toEpochMilli },
-        clockActiveColor = clock.map(_.activeColor.label.toLowerCase),
-        pendingDrawOffer = entry.engine.pendingDrawOfferBy.map(_.label.toLowerCase),
-        result = entry.engine.context.result.map {
-          case GameResult.Win(Color.White, _) => "white"
-          case GameResult.Win(Color.Black, _) => "black"
-          case GameResult.Draw(_)             => "draw"
-        },
-        terminationReason = entry.engine.context.result.map {
-          case GameResult.Win(_, WinReason.Checkmate)           => "checkmate"
-          case GameResult.Win(_, WinReason.Resignation)         => "resignation"
-          case GameResult.Win(_, WinReason.TimeControl)         => "timeout"
-          case GameResult.Draw(DrawReason.Stalemate)            => "stalemate"
-          case GameResult.Draw(DrawReason.InsufficientMaterial) => "insufficient_material"
-          case GameResult.Draw(DrawReason.FiftyMoveRule)        => "fifty_move"
-          case GameResult.Draw(DrawReason.ThreefoldRepetition)  => "repetition"
-          case GameResult.Draw(DrawReason.Agreement)            => "agreement"
-        },
-        redoStack = entry.engine.redoStackMoves.map(GameDtoMapper.moveToUci),
-        pendingTakebackRequest = entry.engine.pendingTakebackRequestBy.map(_.label.toLowerCase),
-      )
-      writebackEmit(objectMapper.writeValueAsString(wb))
-      if entry.engine.context.result.isDefined then onGameOver(gameId)
-    }
+        val clock = entry.engine.currentClockState
+        val wb = GameWritebackEventDto(
+          gameId = gameId,
+          fen = dto.fen,
+          pgn = dto.pgn,
+          moveCount = entry.engine.context.moves.size,
+          whiteId = entry.white.id.value,
+          whiteName = entry.white.displayName,
+          blackId = entry.black.id.value,
+          blackName = entry.black.displayName,
+          mode = entry.mode.toString,
+          resigned = entry.resigned,
+          limitSeconds = entry.engine.timeControl match {
+            case de.nowchess.api.game.TimeControl.Clock(l, _) => Some(l); case _ => None
+          },
+          incrementSeconds = entry.engine.timeControl match {
+            case de.nowchess.api.game.TimeControl.Clock(_, i) => Some(i); case _ => None
+          },
+          daysPerMove = entry.engine.timeControl match {
+            case de.nowchess.api.game.TimeControl.Correspondence(d) => Some(d); case _ => None
+          },
+          whiteRemainingMs = clock.collect { case c: LiveClockState => c.whiteRemainingMs },
+          blackRemainingMs = clock.collect { case c: LiveClockState => c.blackRemainingMs },
+          incrementMs = clock.collect { case c: LiveClockState => c.incrementMs },
+          clockLastTickAt = clock.collect { case c: LiveClockState => c.lastTickAt.toEpochMilli },
+          clockMoveDeadline = clock.collect { case c: CorrespondenceClockState => c.moveDeadline.toEpochMilli },
+          clockActiveColor = clock.map(_.activeColor.label.toLowerCase),
+          pendingDrawOffer = entry.engine.pendingDrawOfferBy.map(_.label.toLowerCase),
+          result = entry.engine.context.result.map {
+            case GameResult.Win(Color.White, _) => "white"
+            case GameResult.Win(Color.Black, _) => "black"
+            case GameResult.Draw(_)             => "draw"
+          },
+          terminationReason = entry.engine.context.result.map {
+            case GameResult.Win(_, WinReason.Checkmate)           => "checkmate"
+            case GameResult.Win(_, WinReason.Resignation)         => "resignation"
+            case GameResult.Win(_, WinReason.TimeControl)         => "timeout"
+            case GameResult.Draw(DrawReason.Stalemate)            => "stalemate"
+            case GameResult.Draw(DrawReason.InsufficientMaterial) => "insufficient_material"
+            case GameResult.Draw(DrawReason.FiftyMoveRule)        => "fifty_move"
+            case GameResult.Draw(DrawReason.ThreefoldRepetition)  => "repetition"
+            case GameResult.Draw(DrawReason.Agreement)            => "agreement"
+          },
+          redoStack = entry.engine.redoStackMoves.map(GameDtoMapper.moveToUci),
+          pendingTakebackRequest = entry.engine.pendingTakebackRequestBy.map(_.label.toLowerCase),
+        )
+        writebackEmit(objectMapper.writeValueAsString(wb))
+        if entry.engine.context.result.isDefined then onGameOver(gameId)
+      }
+    catch case ex: Exception => GameRedisPublisher.log.warnf(ex, "Failed to publish game event for game %s", gameId)

modules/core/src/main/scala/de/nowchess/chess/redis/GameRedisSubscriberManager.scala

@@ -16,6 +16,7 @@ import jakarta.annotation.PreDestroy
 import jakarta.enterprise.context.ApplicationScoped
 import jakarta.enterprise.inject.Instance
 import jakarta.inject.Inject
+import org.jboss.logging.Logger
 import scala.compiletime.uninitialized
 import scala.util.Try
 import java.util.concurrent.ConcurrentHashMap
@@ -24,6 +25,8 @@ import java.util.function.Consumer
 @ApplicationScoped
 class GameRedisSubscriberManager:
 
+  private val log = Logger.getLogger(classOf[GameRedisSubscriberManager])
+
   // scalafix:off DisableSyntax.var
   @Inject var redis: RedisDataSource                                       = uninitialized
   @Inject var registry: GameRegistry                                       = uninitialized
@@ -65,11 +68,12 @@ class GameRedisSubscriberManager:
       )
       s2cObservers.put(gameId, obs)
       registry.get(gameId).foreach(_.engine.subscribe(obs))
+      log.debugf("Subscribed to game %s", gameId)
 
       heartbeatServiceOpt.foreach(_.addGameSubscription(gameId))
     catch
       case e: Exception =>
-        System.err.println(s"Warning: Redis subscription failed for game $gameId: ${e.getMessage}")
+        log.warnf(e, "Redis subscription failed for game %s", gameId)
         ()
 
   def unsubscribeGame(gameId: String): Unit =
@@ -81,6 +85,7 @@ class GameRedisSubscriberManager:
     }
 
     heartbeatServiceOpt.foreach(_.removeGameSubscription(gameId))
+    log.debugf("Unsubscribed from game %s", gameId)
 
   private def handleC2sMessage(gameId: String, msg: String): Unit =
     parseC2sMessage(msg) match
@@ -97,6 +102,7 @@ class GameRedisSubscriberManager:
     }
 
   private def handleMove(gameId: String, uci: String, playerId: Option[String]): Unit =
+    log.debugf("Processing move %s for game %s by player %s", uci, gameId, playerId.getOrElse("anonymous"))
     registry.get(gameId).foreach { entry =>
       entry.mode match
         case GameMode.Open => entry.engine.processUserInput(uci)
@@ -127,6 +133,7 @@ class GameRedisSubscriberManager:
 
   def batchResubscribeGames(gameIds: java.util.List[String]): Int =
     gameIds.forEach(subscribeGame)
+    log.infof("Batch resubscribed %d games", gameIds.size())
     gameIds.size()
 
   def unsubscribeGames(gameIds: java.util.List[String]): Int =
@@ -135,12 +142,14 @@ class GameRedisSubscriberManager:
 
   def evictGames(gameIds: java.util.List[String]): Int =
     gameIds.forEach(unsubscribeGame)
+    log.infof("Evicting %d games", gameIds.size())
     gameIds.size()
 
   def drainInstance(): Int =
     val gameIds = new java.util.ArrayList(c2sListeners.keySet())
     val count   = gameIds.size()
     gameIds.forEach(unsubscribeGame)
+    log.infof("Draining instance, unsubscribing %d games", count)
     count
 
   @PreDestroy

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

@@ -17,6 +17,7 @@ import jakarta.enterprise.context.ApplicationScoped
 import jakarta.inject.Inject
 import org.eclipse.microprofile.rest.client.inject.RestClient
 import scala.compiletime.uninitialized
+import org.jboss.logging.Logger
 import scala.util.Try
 import java.nio.charset.StandardCharsets
 import java.security.{MessageDigest, SecureRandom}
@@ -35,6 +36,7 @@ class RedisGameRegistry extends GameRegistry:
   @Inject @RestClient var storeClient: StoreServiceClient = uninitialized
   // scalafix:on
 
+  private val log          = Logger.getLogger(classOf[RedisGameRegistry])
   private val localEngines = ConcurrentHashMap[String, GameEntry]()
   private val rng          = new SecureRandom()
 
@@ -48,6 +50,12 @@ class RedisGameRegistry extends GameRegistry:
     localEngines.put(entry.gameId, entry)
     val combined = ioClient.exportCombined(entry.engine.context)
     redis.value(classOf[String]).setex(cacheKey(entry.gameId), 1800L, toJson(entry, combined.fen, combined.pgn))
+    log.infof(
+      "Stored game %s in registry (white=%s black=%s)",
+      entry.gameId,
+      entry.white.displayName,
+      entry.black.displayName,
+    )
 
   def get(gameId: String): Option[GameEntry] =
     Option(localEngines.get(gameId)) match
@@ -71,9 +79,15 @@ class RedisGameRegistry extends GameRegistry:
 
   private def fromRedis(gameId: String): Option[GameEntry] =
     readRedisDto(gameId)
-      .flatMap(dto => Try(reconstruct(dto)).toOption)
+      .flatMap { dto =>
+        Try(reconstruct(dto)).toOption.orElse {
+          log.warnf("Failed to reconstruct game %s from Redis", gameId)
+          None
+        }
+      }
       .map { entry =>
         localEngines.put(gameId, entry)
+        log.infof("Loaded game %s from Redis cache", gameId)
         entry
       }
 
@@ -102,12 +116,15 @@ class RedisGameRegistry extends GameRegistry:
         pendingDrawOffer = Option(record.pendingDrawOffer),
       )
       (dto, reconstruct(dto))
-    }.toOption
-      .map { case (dto, entry) =>
+    } match
+      case scala.util.Success((dto, entry)) =>
+        log.infof("Loaded game %s from store service", gameId)
         localEngines.put(gameId, entry)
         redis.value(classOf[String]).setex(cacheKey(gameId), 1800L, objectMapper.writeValueAsString(dto))
-        entry
-      }
+        Some(entry)
+      case scala.util.Failure(ex) =>
+        log.warnf(ex, "Failed to load game %s from store service", gameId)
+        None
 
   private def reconstruct(dto: GameCacheDto): GameEntry =
     val ctx = if dto.pgn.nonEmpty then ioClient.importPgn(dto.pgn) else GameContext.initial

modules/core/src/main/scala/de/nowchess/chess/resource/GameResource.scala

@@ -30,6 +30,7 @@ import jakarta.inject.Inject
 import jakarta.ws.rs.*
 import jakarta.ws.rs.core.{MediaType, Response}
 import org.eclipse.microprofile.jwt.JsonWebToken
+import org.jboss.logging.Logger
 
 import java.util.concurrent.atomic.AtomicReference
 import scala.compiletime.uninitialized
@@ -38,6 +39,8 @@ import scala.compiletime.uninitialized
 @ApplicationScoped
 class GameResource:
 
+  private val log = Logger.getLogger(classOf[GameResource])
+
   // scalafix:off DisableSyntax.var
   @Inject
   var registry: GameRegistry = uninitialized
@@ -165,7 +168,13 @@ class GameResource:
     val entry = newEntry(GameContext.initial, white, black, tc, mode)
     registry.store(entry)
     subscriberManager.subscribeGame(entry.gameId)
-    println(s"Created game ${entry.gameId}")
+    log.infof(
+      "Game %s created — white=%s black=%s mode=%s",
+      entry.gameId,
+      white.displayName,
+      black.displayName,
+      mode.toString,
+    )
     created(GameDtoMapper.toGameFullDto(entry, ioClient))
 
   @GET
@@ -182,6 +191,7 @@ class GameResource:
     val entry = registry.get(gameId).getOrElse(throw GameNotFoundException(gameId))
     assertGameNotOver(entry)
     val color = colorOf(entry)
+    log.infof("Game %s — resign by %s", gameId, color.label)
     entry.engine.resign(color)
     registry.update(entry.copy(resigned = true))
     ok(OkResponseDto())
@@ -194,6 +204,7 @@ class GameResource:
     val entry = registry.get(gameId).getOrElse(throw GameNotFoundException(gameId))
     assertGameNotOver(entry)
     assertIsCurrentPlayer(entry)
+    log.debugf("Game %s — move %s by %s", gameId, uci, colorOf(entry).label)
     if Parser.parseMove(uci).isEmpty then
       throw BadRequestException("INVALID_UCI", s"Invalid UCI notation: $uci", Some("uci"))
     applyMoveInput(entry.engine, uci).foreach(err => throw BadRequestException("INVALID_MOVE", err, Some("uci")))
@@ -284,6 +295,7 @@ class GameResource:
     val entry = newEntry(ctx, white, black, tc)
     registry.store(entry)
     subscriberManager.subscribeGame(entry.gameId)
+    log.infof("Imported FEN game %s", entry.gameId)
     created(GameDtoMapper.toGameFullDto(entry, ioClient))
 
   @POST
@@ -295,6 +307,7 @@ class GameResource:
     val entry = newEntry(ctx, DefaultWhite, DefaultBlack)
     registry.store(entry)
     subscriberManager.subscribeGame(entry.gameId)
+    log.infof("Imported PGN game %s", entry.gameId)
     created(GameDtoMapper.toGameFullDto(entry, ioClient))
 
   @GET