[jira] [Created] (KAFKA-7620) ConfigProvider is broken for connect when TTL is not null

["Ye Ji (JIRA)" <ji...@apache.org>]

Ye Ji created KAFKA-7620:
----------------------------

             Summary: ConfigProvider is broken for connect when TTL is not null
                 Key: KAFKA-7620
                 URL: https://issues.apache.org/jira/browse/KAFKA-7620
             Project: Kafka
          Issue Type: Bug
          Components: KafkaConnect
    Affects Versions: 2.0.1
            Reporter: Ye Ji


If the ConfigData returned by ConfigProvider.get implementations has non-null and non-negative ttl, it will trigger infinite recursion, here is an excerpt of the stack trace:
{code:java}
at org.apache.kafka.connect.runtime.WorkerConfigTransformer.scheduleReload(WorkerConfigTransformer.java:62)
	at org.apache.kafka.connect.runtime.WorkerConfigTransformer.scheduleReload(WorkerConfigTransformer.java:56)
	at org.apache.kafka.connect.runtime.WorkerConfigTransformer.transform(WorkerConfigTransformer.java:49)
	at org.apache.kafka.connect.runtime.distributed.ClusterConfigState.connectorConfig(ClusterConfigState.java:121)
	at org.apache.kafka.connect.runtime.distributed.DistributedHerder.connectorConfigReloadAction(DistributedHerder.java:648)
	at org.apache.kafka.connect.runtime.WorkerConfigTransformer.scheduleReload(WorkerConfigTransformer.java:62)
	at org.apache.kafka.connect.runtime.WorkerConfigTransformer.scheduleReload(WorkerConfigTransformer.java:56)
	at org.apache.kafka.connect.runtime.WorkerConfigTransformer.transform(WorkerConfigTransformer.java:49)
{code}


Basically, 
1) if a non-null ttl is returned from the config provider, connect runtime will try to schedule a reload in the future, 
2) scheduleReload function reads the config again to see if it is a restart or not, by calling org.apache.kafka.connect.runtime.WorkerConfigTransformer.transform to transform the config
3) the transform function calls config provider, and gets a non-null ttl, causing scheduleReload being called, we are back to step 1.


To reproduce, simply fork the provided FileConfigProvider, and add a non-negative ttl to the ConfigData returned by the get functions.



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