[Bug] batch recovery crashes startup on null request_conf (KyuubiConf.set)

[moelhoussein]

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Describe the bug

When Batch API v2 is enabled, Kyuubi persists batch requests’ conf map to the metadata store without null validation. On server restart, recovery loads these rows and constructs KyuubiBatchSession from metadata.request_conf. If any key has a null value (e.g., "sfPassword": null), KyuubiConf.set throws IllegalArgumentException (“value cannot be null for key: …”) during session construction in getBatchSessionsToRecover, which propagates and causes KyuubiRestFrontendService startup to fail.

Expected
the offending batch should be skipped/marked ERROR and startup should continue;

Actual
server startup aborts on the uncaught exception.

Affects Version(s)

master

Kyuubi Server Log Output

2025-11-15 02:53:58.945 ERROR org.apache.kyuubi.server.KyuubiServer: Error starting service KyuubiRestFrontendService
org.apache.kyuubi.KyuubiException: Cannot start KyuubiRestFrontendService
        at org.apache.kyuubi.server.KyuubiRestFrontendService.start(KyuubiRestFrontendService.scala:239)
        at org.apache.kyuubi.service.CompositeService.$anonfun$start$1(CompositeService.scala:47)
        at org.apache.kyuubi.service.CompositeService.$anonfun$start$1$adapted(CompositeService.scala:45)
        at scala.collection.mutable.ResizableArray.foreach(ResizableArray.scala:62)
        at scala.collection.mutable.ResizableArray.foreach$(ResizableArray.scala:55)
        at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:49)
        at org.apache.kyuubi.service.CompositeService.start(CompositeService.scala:45)
        at org.apache.kyuubi.service.Serverable.start(Serverable.scala:53)
        at org.apache.kyuubi.server.KyuubiServer.start(KyuubiServer.scala:225)
        at org.apache.kyuubi.server.KyuubiServer$.startServer(KyuubiServer.scala:69)
        at org.apache.kyuubi.server.KyuubiServer$.main(KyuubiServer.scala:104)
        at org.apache.kyuubi.server.KyuubiServer.main(KyuubiServer.scala)
Caused by: java.lang.IllegalArgumentException: requirement failed: value cannot be null for key: sfPassword
        at scala.Predef$.require(Predef.scala:281)
        at org.apache.kyuubi.config.KyuubiConf.set(KyuubiConf.scala:79)
        at org.apache.kyuubi.session.KyuubiBatchSession.$anonfun$new$1(KyuubiBatchSession.scala:102)
        at scala.collection.immutable.HashMap$HashMap1.foreach(HashMap.scala:400)
        at scala.collection.immutable.HashMap$HashTrieMap.foreach(HashMap.scala:728)
        at scala.collection.immutable.HashMap$HashTrieMap.foreach(HashMap.scala:728)
        at org.apache.kyuubi.session.KyuubiBatchSession.<init>(KyuubiBatchSession.scala:101)
        at org.apache.kyuubi.session.KyuubiSessionManager.createBatchSession(KyuubiSessionManager.scala:174)
        at org.apache.kyuubi.session.KyuubiSessionManager.$anonfun$getBatchSessionsToRecover$3(KyuubiSessionManager.scala:326)
        at scala.collection.immutable.List.map(List.scala:293)
        at org.apache.kyuubi.session.KyuubiSessionManager.$anonfun$getBatchSessionsToRecover$2(KyuubiSessionManager.scala:314)
        at scala.Option.map(Option.scala:230)
        at org.apache.kyuubi.session.KyuubiSessionManager.$anonfun$getBatchSessionsToRecover$1(KyuubiSessionManager.scala:314)
        at scala.collection.immutable.List.flatMap(List.scala:366)
        at org.apache.kyuubi.session.KyuubiSessionManager.getBatchSessionsToRecover(KyuubiSessionManager.scala:309)
        at org.apache.kyuubi.server.KyuubiRestFrontendService.recoverBatchSessions(KyuubiRestFrontendService.scala:176)
        at org.apache.kyuubi.server.KyuubiRestFrontendService.start(KyuubiRestFrontendService.scala:234)
        ... 11 more
2025-11-15 02:53:58.947 INFO org.apache.kyuubi.server.KyuubiServer: Service: [KyuubiBackendService] is stopping.
2025-11-15 02:53:58.947 INFO org.apache.kyuubi.server.KyuubiServer: Service: [KyuubiSessionManager] is stopping.
2025-11-15 02:53:58.947 INFO org.apache.kyuubi.session.KyuubiSessionManager: Service: [KyuubiOperationManager] is stopping.
2025-11-15 02:53:58.948 INFO org.apache.kyuubi.operation.KyuubiOperationManager: Service[KyuubiOperationManager] is stopped.
2025-11-15 02:53:58.948 INFO org.apache.kyuubi.session.KyuubiSessionManager: Service: [MetadataManager] is stopping.
2025-11-15 02:53:58.949 INFO com.zaxxer.hikari.HikariDataSource: jdbc-metadata-store-pool - Shutdown initiated...
2025-11-15 02:53:58.949 DEBUG com.zaxxer.hikari.pool.HikariPool: jdbc-metadata-store-pool - Before shutdown stats (total=9, active=0, idle=9, waiting=0)
2025-11-15 02:53:58.978 DEBUG com.zaxxer.hikari.pool.HikariPool: jdbc-metadata-store-pool - Added connection org.postgresql.jdbc.PgConnection@7689f3b5
2025-11-15 02:53:59.073 DEBUG com.zaxxer.hikari.pool.HikariPool: jdbc-metadata-store-pool - After shutdown stats (total=0, active=0, idle=0, waiting=0)
2025-11-15 02:53:59.073 INFO com.zaxxer.hikari.HikariDataSource: jdbc-metadata-store-pool - Shutdown completed.
2025-11-15 02:53:59.074 INFO org.apache.kyuubi.server.metadata.MetadataManager: Service[MetadataManager] is stopped.

Kyuubi Engine Log Output

N/A

Kyuubi Server Configurations

kyuubi.session.engine.startup.waitCompletion=false
kyuubi.batch.impl.version=2
kyuubi.batch.submitter.enabled=true
kyuubi.batch.submitter.threads=10

Kyuubi Engine Configurations

N/A

Additional context

No response

Are you willing to submit PR?

• Yes. I would be willing to submit a PR with guidance from the Kyuubi community to fix.
• No. I cannot submit a PR at this time.