Prevent concurrent insert of sessions

FAForever · Nov 3, 2023 · fcce220 · fcce220
1 parent 3740f35
commit fcce220
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Showing 2 changed files with 31 additions and 12 deletions.
diff --git a/src/main/kotlin/com/faforever/icebreaker/persistence/IceSessionEntity.kt b/src/main/kotlin/com/faforever/icebreaker/persistence/IceSessionEntity.kt
@@ -28,4 +28,17 @@ class IceSessionRepository : PanacheRepository<IceSessionEntity> {
 
     fun findByCreatedAtLesserThan(instant: Instant) =
         find("createdAt <= ?1", instant).list()
+
+    fun acquireGameLock(gameId: Long, timeout: Int = 10) {
+        getEntityManager().createNativeQuery("SELECT GET_LOCK(:lockName,:timeout)", Boolean::class.java).apply {
+            setParameter("lockName", "game_id_$gameId")
+            setParameter("timeout", timeout)
+        }.singleResult
+    }
+
+    fun releaseGameLock(gameId: Long) {
+        getEntityManager().createNativeQuery("SELECT RELEASE_LOCK(:lockName)", Boolean::class.java).apply {
+            setParameter("lockName", "game_id_$gameId")
+        }.singleResult
+    }
 }
diff --git a/src/main/kotlin/com/faforever/icebreaker/service/SessionService.kt b/src/main/kotlin/com/faforever/icebreaker/service/SessionService.kt
@@ -26,21 +26,27 @@ class SessionService(
 
     @Transactional
     fun getSession(gameId: Long): Session {
-        val session = iceSessionRepository.findByGameId(gameId)
-            ?: IceSessionEntity(gameId = gameId, createdAt = Instant.now()).also {
-                LOG.debug("Creating session for gameId $gameId")
-                iceSessionRepository.persist(it)
+        try {
+            iceSessionRepository.acquireGameLock(gameId)
+
+            val session = iceSessionRepository.findByGameId(gameId)
+                ?: IceSessionEntity(gameId = gameId, createdAt = Instant.now()).also {
+                    LOG.debug("Creating session for gameId $gameId")
+                    iceSessionRepository.persist(it)
+                }
+
+            val servers = activeSessionHandlers.flatMap {
+                it.createSession(session.id)
+                it.getIceServersSession(session.id)
             }
 
-        val servers = activeSessionHandlers.flatMap {
-            it.createSession(session.id)
-            it.getIceServersSession(session.id)
+            return Session(
+                id = session.id,
+                servers = servers,
+            )
+        } finally {
+            iceSessionRepository.releaseGameLock(gameId)
         }
-
-        return Session(
-            id = session.id,
-            servers = servers,
-        )
     }
 
     @Transactional