[KAFKA-8591] NPE when reloading connector configuration using WorkerConfigTransformer

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.2.1
• Fix Version/s: 2.2.2, 2.3.1
• Component/s: connect
• Assignee: Robert Yokota
• Reporter: Nacho Munoz
• Created: 24/Jun/19 12:10
• Updated: 09/Jul/19 06:10
• Resolved: 09/Jul/19 06:10

Description

When a connector uses a ConfigProvider and sets a given TTL in the returned ConfigData, it is expected that WorkerConfigTransformer will periodically reload the connector configuration. The problem is that when the TTL expires a NPE is raised. 

[2019-06-17 14:34:12,320] INFO Scheduling a restart of connector workshop-incremental in 60000 ms (org.apache.kafka.connect.runtime.WorkerConfigTransformer:88)
[2019-06-17 14:34:12,321] ERROR Uncaught exception in herder work thread, exiting: (org.apache.kafka.connect.runtime.distributed.DistributedHerder:227)
java.lang.NullPointerException
at org.apache.kafka.connect.runtime.distributed.DistributedHerder$19.onCompletion(DistributedHerder.java:1187)
at org.apache.kafka.connect.runtime.distributed.DistributedHerder$19.onCompletion(DistributedHerder.java:1183)
at org.apache.kafka.connect.runtime.distributed.DistributedHerder.tick(DistributedHerder.java:273)
at org.apache.kafka.connect.runtime.distributed.DistributedHerder.run(DistributedHerder.java:219)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:834)

The reason is that WorkerConfigTransformer is passing a null callback to the herder's restartConnector method.

Issue Links

• links to: GitHub Pull Request #6991