Kafka Connect S3 source throws java.io.IOException - amazon-s3

Question

Kafka Connect S3 source connector throws the following exception around 20 seconds into reading an S3 bucket:
Caused by: java.io.IOException: Attempted read on closed stream.
at org.apache.http.conn.EofSensorInputStream.isReadAllowed(EofSensorInputStream.java:107)
at org.apache.http.conn.EofSensorInputStream.read(EofSensorInputStream.java:133)
at com.amazonaws.internal.SdkFilterInputStream.read(SdkFilterInputStream.java:90)
at com.amazonaws.event.ProgressInputStream.read(ProgressInputStream.java:180)
The error is preceded by the following warnning:
WARN Not all bytes were read from the S3ObjectInputStream, aborting HTTP connection. This is likely an error and may result in sub-optimal behavior. Request only the bytes you need via a ranged GET or drain the input stream after use. (com.amazonaws.services.s3.internal.S3AbortableInputStream:178)
I am running Kafka connect out of this image: confluentinc/cp-kafka-connect-base:6.2.0. Using the confluentinc-kafka-connect-s3-source-2.1.1 jar.
My source connector configuration looks like so:
{
"connector.class":"io.confluent.connect.s3.source.S3SourceConnector",
"tasks.max":"1",
"s3.region":"eu-central-1",
"s3.bucket.name":"test-bucket-yordan",
"topics.dir":"test-bucket/topics",
"format.class": "io.confluent.connect.s3.format.json.JsonFormat",
"partitioner.class":"io.confluent.connect.storage.partitioner.DefaultPartitioner",
"schema.compatibility":"NONE",
"confluent.topic.bootstrap.servers": "blockchain-kafka-kafka-0.blockchain-kafka-kafka-headless.default.svc.cluster.local:9092",
"transforms":"AddPrefix",
"transforms.AddPrefix.type":"org.apache.kafka.connect.transforms.RegexRouter",
"transforms.AddPrefix.regex":".*",
"transforms.AddPrefix.replacement":"$0_copy"
}
Any ideas on what might be the issue? Also I was unable to find the repository of Kafka connect S3 source connector, is it opensource?
Edit: I don't see the problem if gzip compression on the kafka-connect sink is disabled.

Answer 1

The warning means that close()was called before the file was read. S3 was not done with sending the data but the connection was left hanging.
2 options:
Validate that the input stream contains no more data. That way the connection can be reused
Call s3ObjectInputStream.abort() (NOTE: this connection could not be reused if you abort the input stream and a new one will need to created which will have performance impact.) In some cases this might make sense e.g. when the read is getting too slow etc.