[SPARK-30336][SQL][SS] Move Kafka consumer-related classes to its own package

### What changes were proposed in this pull request?

There're too many classes placed in a single package "org.apache.spark.sql.kafka010" which classes can be grouped by purpose.

As a part of change in SPARK-21869 (#26845), we moved out producer related classes to "org.apache.spark.sql.kafka010.producer" and only expose necessary classes/methods to the outside of package. This patch applies the same to consumer related classes.

### Why are the changes needed?

Described above.

### Does this PR introduce any user-facing change?

No.

### How was this patch tested?

Existing UTs.

Closes #26991 from HeartSaVioR/SPARK-30336.

Authored-by: Jungtaek Lim (HeartSaVioR) <kabhwan.opensource@gmail.com>
Signed-off-by: Sean Owen <srowen@gmail.com>

external/kafka-0-10-sql/src/main/scala/org/apache/spark/sql/kafka010/KafkaBatchPartitionReader.scala

@@ -23,6 +23,7 @@ import org.apache.spark.internal.Logging
 import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.expressions.UnsafeRow
 import org.apache.spark.sql.connector.read.{InputPartition, PartitionReader, PartitionReaderFactory}
+import org.apache.spark.sql.kafka010.consumer.KafkaDataConsumer
 
 /** A [[InputPartition]] for reading Kafka data in a batch based streaming query. */
 private[kafka010] case class KafkaBatchInputPartition(

external/kafka-0-10-sql/src/main/scala/org/apache/spark/sql/kafka010/KafkaContinuousStream.scala

@@ -30,6 +30,7 @@ import org.apache.spark.sql.catalyst.expressions.UnsafeRow
 import org.apache.spark.sql.connector.read.InputPartition
 import org.apache.spark.sql.connector.read.streaming.{ContinuousPartitionReader, ContinuousPartitionReaderFactory, ContinuousStream, Offset, PartitionOffset}
 import org.apache.spark.sql.kafka010.KafkaSourceProvider._
+import org.apache.spark.sql.kafka010.consumer.KafkaDataConsumer
 import org.apache.spark.sql.util.CaseInsensitiveStringMap
 
 /**

external/kafka-0-10-sql/src/main/scala/org/apache/spark/sql/kafka010/KafkaSourceRDD.scala

@@ -19,18 +19,15 @@ package org.apache.spark.sql.kafka010
 
 import java.{util => ju}
 
-import scala.collection.mutable.ArrayBuffer
+import org.apache.kafka.clients.consumer.ConsumerRecord
-
-import org.apache.kafka.clients.consumer.{ConsumerConfig, ConsumerRecord}
 import org.apache.kafka.common.TopicPartition
 
 import org.apache.spark.{Partition, SparkContext, TaskContext}
-import org.apache.spark.partial.{BoundedDouble, PartialResult}
 import org.apache.spark.rdd.RDD
+import org.apache.spark.sql.kafka010.consumer.KafkaDataConsumer
 import org.apache.spark.storage.StorageLevel
 import org.apache.spark.util.NextIterator
 
-
 /** Offset range that one partition of the KafkaSourceRDD has to read */
 private[kafka010] case class KafkaSourceRDDOffsetRange(
     topicPartition: TopicPartition,

external/kafka-0-10-sql/src/main/scala/org/apache/spark/sql/kafka010/consumer/FetchedDataPool.scala

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.sql.kafka010
+package org.apache.spark.sql.kafka010.consumer
 
 import java.{util => ju}
 import java.util.concurrent.{ScheduledExecutorService, ScheduledFuture, TimeUnit}
@@ -27,7 +27,8 @@ import org.apache.kafka.clients.consumer.ConsumerRecord
 
 import org.apache.spark.SparkConf
 import org.apache.spark.internal.Logging
-import org.apache.spark.sql.kafka010.KafkaDataConsumer.{CacheKey, UNKNOWN_OFFSET}
+import org.apache.spark.sql.kafka010.{FETCHED_DATA_CACHE_EVICTOR_THREAD_RUN_INTERVAL, FETCHED_DATA_CACHE_TIMEOUT}
+import org.apache.spark.sql.kafka010.consumer.KafkaDataConsumer.{CacheKey, UNKNOWN_OFFSET}
 import org.apache.spark.util.{Clock, SystemClock, ThreadUtils, Utils}
 
 /**
@@ -39,7 +40,7 @@ import org.apache.spark.util.{Clock, SystemClock, ThreadUtils, Utils}
  * modified in same instance, this class cannot be replaced with general pool implementations
  * including Apache Commons Pool which pools KafkaConsumer.
  */
-private[kafka010] class FetchedDataPool(
+private[consumer] class FetchedDataPool(
     executorService: ScheduledExecutorService,
     clock: Clock,
     conf: SparkConf) extends Logging {
@@ -159,8 +160,8 @@ private[kafka010] class FetchedDataPool(
   }
 }
 
-private[kafka010] object FetchedDataPool {
+private[consumer] object FetchedDataPool {
-  private[kafka010] case class CachedFetchedData(fetchedData: FetchedData) {
+  private[consumer] case class CachedFetchedData(fetchedData: FetchedData) {
     var lastReleasedTimestamp: Long = Long.MaxValue
     var lastAcquiredTimestamp: Long = Long.MinValue
     var inUse: Boolean = false
@@ -179,5 +180,5 @@ private[kafka010] object FetchedDataPool {
     }
   }
 
-  private[kafka010] type CachedFetchedDataList = mutable.ListBuffer[CachedFetchedData]
+  private[consumer] type CachedFetchedDataList = mutable.ListBuffer[CachedFetchedData]
 }

external/kafka-0-10-sql/src/main/scala/org/apache/spark/sql/kafka010/consumer/InternalKafkaConsumerPool.scala

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.sql.kafka010
+package org.apache.spark.sql.kafka010.consumer
 
 import java.{util => ju}
 import java.util.concurrent.ConcurrentHashMap
@@ -25,8 +25,9 @@ import org.apache.commons.pool2.impl.{DefaultEvictionPolicy, DefaultPooledObject
 
 import org.apache.spark.SparkConf
 import org.apache.spark.internal.Logging
-import org.apache.spark.sql.kafka010.InternalKafkaConsumerPool._
+import org.apache.spark.sql.kafka010._
-import org.apache.spark.sql.kafka010.KafkaDataConsumer.CacheKey
+import org.apache.spark.sql.kafka010.consumer.InternalKafkaConsumerPool._
+import org.apache.spark.sql.kafka010.consumer.KafkaDataConsumer.CacheKey
 
 /**
  * Provides object pool for [[InternalKafkaConsumer]] which is grouped by [[CacheKey]].
@@ -45,10 +46,9 @@ import org.apache.spark.sql.kafka010.KafkaDataConsumer.CacheKey
  * not yet returned, hence provide thread-safety usage of non-thread-safe [[InternalKafkaConsumer]]
  * unless caller shares the object to multiple threads.
  */
-private[kafka010] class InternalKafkaConsumerPool(
+private[consumer] class InternalKafkaConsumerPool(
     objectFactory: ObjectFactory,
     poolConfig: PoolConfig) extends Logging {
-
   def this(conf: SparkConf) = {
     this(new ObjectFactory, new PoolConfig(conf))
   }
@@ -147,7 +147,7 @@ private[kafka010] class InternalKafkaConsumerPool(
   }
 }
 
-private[kafka010] object InternalKafkaConsumerPool {
+private[consumer] object InternalKafkaConsumerPool {
   object CustomSwallowedExceptionListener extends SwallowedExceptionListener with Logging {
     override def onSwallowException(e: Exception): Unit = {
       logError(s"Error closing Kafka consumer", e)
@@ -218,4 +218,3 @@ private[kafka010] object InternalKafkaConsumerPool {
     }
   }
 }
-

external/kafka-0-10-sql/src/main/scala/org/apache/spark/sql/kafka010/consumer/KafkaDataConsumer.scala

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.sql.kafka010
+package org.apache.spark.sql.kafka010.consumer
 
 import java.{util => ju}
 import java.io.Closeable
@@ -29,9 +29,9 @@ import org.apache.kafka.common.TopicPartition
 
 import org.apache.spark.{SparkEnv, TaskContext}
 import org.apache.spark.internal.Logging
-import org.apache.spark.kafka010.{KafkaConfigUpdater, KafkaTokenClusterConf, KafkaTokenUtil}
+import org.apache.spark.kafka010.{KafkaConfigUpdater, KafkaTokenUtil}
-import org.apache.spark.sql.kafka010.KafkaDataConsumer.{AvailableOffsetRange, UNKNOWN_OFFSET}
 import org.apache.spark.sql.kafka010.KafkaSourceProvider._
+import org.apache.spark.sql.kafka010.consumer.KafkaDataConsumer.{AvailableOffsetRange, UNKNOWN_OFFSET}
 import org.apache.spark.util.{ShutdownHookManager, UninterruptibleThread}
 
 /**
@@ -47,13 +47,15 @@ private[kafka010] class InternalKafkaConsumer(
 
   val groupId = kafkaParams.get(ConsumerConfig.GROUP_ID_CONFIG).asInstanceOf[String]
 
-  private[kafka010] val clusterConfig = KafkaTokenUtil.findMatchingTokenClusterConfig(
+  // Exposed for testing
+  private[consumer] val clusterConfig = KafkaTokenUtil.findMatchingTokenClusterConfig(
     SparkEnv.get.conf, kafkaParams.get(CommonClientConfigs.BOOTSTRAP_SERVERS_CONFIG)
       .asInstanceOf[String])
 
   // Kafka consumer is not able to give back the params instantiated with so we need to store it.
   // It must be updated whenever a new consumer is created.
-  private[kafka010] var kafkaParamsWithSecurity: ju.Map[String, Object] = _
+  // Exposed for testing
+  private[consumer] var kafkaParamsWithSecurity: ju.Map[String, Object] = _
   private val consumer = createConsumer()
 
   /**
@@ -139,7 +141,7 @@ private[kafka010] class InternalKafkaConsumer(
  * @param _offsetAfterPoll the Kafka offset after calling `poll`. We will use this offset to
  *                           poll when `records` is drained.
  */
-private[kafka010] case class FetchedData(
+private[consumer] case class FetchedData(
     private var _records: ju.ListIterator[ConsumerRecord[Array[Byte], Array[Byte]]],
     private var _nextOffsetInFetchedData: Long,
     private var _offsetAfterPoll: Long) {
@@ -196,7 +198,7 @@ private[kafka010] case class FetchedData(
  * `isolation.level` is `read_committed`), and the caller should use `nextOffsetToFetch` to fetch
  * instead.
  */
-private[kafka010] case class FetchedRecord(
+private[consumer] case class FetchedRecord(
     var record: ConsumerRecord[Array[Byte], Array[Byte]],
     var nextOffsetToFetch: Long) {
 
@@ -223,7 +225,8 @@ private[kafka010] class KafkaDataConsumer(
     fetchedDataPool: FetchedDataPool) extends Logging {
   import KafkaDataConsumer._
 
-  @volatile private[kafka010] var _consumer: Option[InternalKafkaConsumer] = None
+  // Exposed for testing
+  @volatile private[consumer] var _consumer: Option[InternalKafkaConsumer] = None
   @volatile private var _fetchedData: Option[FetchedData] = None
 
   private val groupId = kafkaParams.get(ConsumerConfig.GROUP_ID_CONFIG).asInstanceOf[String]

external/kafka-0-10-sql/src/test/scala/org/apache/spark/sql/kafka010/consumer/FetchedDataPoolSuite.scala

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.sql.kafka010
+package org.apache.spark.sql.kafka010.consumer
 
 import java.{util => ju}
 import java.util.concurrent.TimeUnit
@@ -29,7 +29,8 @@ import org.jmock.lib.concurrent.DeterministicScheduler
 import org.scalatest.PrivateMethodTester
 
 import org.apache.spark.SparkConf
-import org.apache.spark.sql.kafka010.KafkaDataConsumer.CacheKey
+import org.apache.spark.sql.kafka010.{FETCHED_DATA_CACHE_EVICTOR_THREAD_RUN_INTERVAL, FETCHED_DATA_CACHE_TIMEOUT}
+import org.apache.spark.sql.kafka010.consumer.KafkaDataConsumer.CacheKey
 import org.apache.spark.sql.test.SharedSparkSession
 import org.apache.spark.util.ManualClock
 

external/kafka-0-10-sql/src/test/scala/org/apache/spark/sql/kafka010/consumer/InternalKafkaConsumerPoolSuite.scala

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.sql.kafka010
+package org.apache.spark.sql.kafka010.consumer
 
 import java.{util => ju}
 
@@ -26,7 +26,8 @@ import org.apache.kafka.common.TopicPartition
 import org.apache.kafka.common.serialization.ByteArrayDeserializer
 
 import org.apache.spark.SparkConf
-import org.apache.spark.sql.kafka010.KafkaDataConsumer.CacheKey
+import org.apache.spark.sql.kafka010.{CONSUMER_CACHE_CAPACITY, CONSUMER_CACHE_EVICTOR_THREAD_RUN_INTERVAL, CONSUMER_CACHE_TIMEOUT}
+import org.apache.spark.sql.kafka010.consumer.KafkaDataConsumer.CacheKey
 import org.apache.spark.sql.test.SharedSparkSession
 
 class InternalKafkaConsumerPoolSuite extends SharedSparkSession {

external/kafka-0-10-sql/src/test/scala/org/apache/spark/sql/kafka010/consumer/KafkaDataConsumerSuite.scala

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark.sql.kafka010
+package org.apache.spark.sql.kafka010.consumer
 
 import java.{util => ju}
 import java.nio.charset.StandardCharsets
@@ -32,7 +32,8 @@ import org.scalatest.PrivateMethodTester
 
 import org.apache.spark.{TaskContext, TaskContextImpl}
 import org.apache.spark.kafka010.KafkaDelegationTokenTest
-import org.apache.spark.sql.kafka010.KafkaDataConsumer.CacheKey
+import org.apache.spark.sql.kafka010.{KafkaTestUtils, RecordBuilder}
+import org.apache.spark.sql.kafka010.consumer.KafkaDataConsumer.CacheKey
 import org.apache.spark.sql.test.SharedSparkSession
 
 class KafkaDataConsumerSuite