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GroupMetadataManager.scala
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GroupMetadataManager.scala
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package kafka.coordinator.group
import java.io.PrintStream
import java.nio.ByteBuffer
import java.nio.charset.StandardCharsets
import java.util.Optional
import java.util.concurrent.TimeUnit
import java.util.concurrent.atomic.AtomicBoolean
import java.util.concurrent.locks.ReentrantLock
import com.yammer.metrics.core.Gauge
import kafka.api.{ApiVersion, KAFKA_0_10_1_IV0, KAFKA_2_1_IV0, KAFKA_2_1_IV1, KAFKA_2_3_IV0}
import kafka.common.OffsetAndMetadata
import kafka.log.AppendOrigin
import kafka.metrics.KafkaMetricsGroup
import kafka.server.{FetchLogEnd, ReplicaManager}
import kafka.utils.CoreUtils.inLock
import kafka.utils._
import kafka.zk.KafkaZkClient
import org.apache.kafka.clients.consumer.ConsumerRecord
import org.apache.kafka.clients.consumer.internals.ConsumerProtocol
import org.apache.kafka.common.internals.Topic
import org.apache.kafka.common.metrics.Metrics
import org.apache.kafka.common.metrics.stats.{Avg, Max, Meter}
import org.apache.kafka.common.protocol.Errors
import org.apache.kafka.common.protocol.types.Type._
import org.apache.kafka.common.protocol.types._
import org.apache.kafka.common.record._
import org.apache.kafka.common.requests.OffsetFetchResponse.PartitionData
import org.apache.kafka.common.requests.ProduceResponse.PartitionResponse
import org.apache.kafka.common.requests.{OffsetCommitRequest, OffsetFetchResponse}
import org.apache.kafka.common.utils.{Time, Utils}
import org.apache.kafka.common.{KafkaException, MessageFormatter, TopicPartition}
import scala.collection._
import scala.collection.mutable.ArrayBuffer
import scala.jdk.CollectionConverters._
class GroupMetadataManager(brokerId: Int,
interBrokerProtocolVersion: ApiVersion,
config: OffsetConfig,
val replicaManager: ReplicaManager,
zkClient: KafkaZkClient,
time: Time,
metrics: Metrics) extends Logging with KafkaMetricsGroup {
private val compressionType: CompressionType = CompressionType.forId(config.offsetsTopicCompressionCodec.codec)
private val groupMetadataCache = new Pool[String, GroupMetadata]
/* lock protecting access to loading and owned partition sets */
private val partitionLock = new ReentrantLock()
/* partitions of consumer groups that are being loaded, its lock should be always called BEFORE the group lock if needed */
private val loadingPartitions: mutable.Set[Int] = mutable.Set()
/* partitions of consumer groups that are assigned, using the same loading partition lock */
private val ownedPartitions: mutable.Set[Int] = mutable.Set()
/* shutting down flag */
private val shuttingDown = new AtomicBoolean(false)
/* number of partitions for the consumer metadata topic */
private val groupMetadataTopicPartitionCount = getGroupMetadataTopicPartitionCount
/* single-thread scheduler to handle offset/group metadata cache loading and unloading */
private val scheduler = new KafkaScheduler(threads = 1, threadNamePrefix = "group-metadata-manager-")
/* The groups with open transactional offsets commits per producer. We need this because when the commit or abort
* marker comes in for a transaction, it is for a particular partition on the offsets topic and a particular producerId.
* We use this structure to quickly find the groups which need to be updated by the commit/abort marker. */
private val openGroupsForProducer = mutable.HashMap[Long, mutable.Set[String]]()
/* setup metrics*/
private val partitionLoadSensor = metrics.sensor(GroupMetadataManager.LoadTimeSensor)
partitionLoadSensor.add(metrics.metricName("partition-load-time-max",
GroupMetadataManager.MetricsGroup,
"The max time it took to load the partitions in the last 30sec"), new Max())
partitionLoadSensor.add(metrics.metricName("partition-load-time-avg",
GroupMetadataManager.MetricsGroup,
"The avg time it took to load the partitions in the last 30sec"), new Avg())
val offsetCommitsSensor = metrics.sensor("OffsetCommits")
offsetCommitsSensor.add(new Meter(
metrics.metricName("offset-commit-rate",
"group-coordinator-metrics",
"The rate of committed offsets"),
metrics.metricName("offset-commit-count",
"group-coordinator-metrics",
"The total number of committed offsets")))
val offsetExpiredSensor = metrics.sensor("OffsetExpired")
offsetExpiredSensor.add(new Meter(
metrics.metricName("offset-expiration-rate",
"group-coordinator-metrics",
"The rate of expired offsets"),
metrics.metricName("offset-expiration-count",
"group-coordinator-metrics",
"The total number of expired offsets")))
this.logIdent = s"[GroupMetadataManager brokerId=$brokerId] "
private def recreateGauge[T](name: String, gauge: Gauge[T]): Gauge[T] = {
removeMetric(name)
newGauge(name, gauge)
}
recreateGauge("NumOffsets",
() => groupMetadataCache.values.map { group =>
group.inLock { group.numOffsets }
}.sum
)
recreateGauge("NumGroups",
() => groupMetadataCache.size
)
recreateGauge("NumGroupsPreparingRebalance",
() => groupMetadataCache.values.count { group =>
group synchronized {
group.is(PreparingRebalance)
}
})
recreateGauge("NumGroupsCompletingRebalance",
() => groupMetadataCache.values.count { group =>
group synchronized {
group.is(CompletingRebalance)
}
})
recreateGauge("NumGroupsStable",
() => groupMetadataCache.values.count { group =>
group synchronized {
group.is(Stable)
}
})
recreateGauge("NumGroupsDead",
() => groupMetadataCache.values.count { group =>
group synchronized {
group.is(Dead)
}
})
recreateGauge("NumGroupsEmpty",
() => groupMetadataCache.values.count { group =>
group synchronized {
group.is(Empty)
}
})
def startup(enableMetadataExpiration: Boolean): Unit = {
scheduler.startup()
if (enableMetadataExpiration) {
scheduler.schedule(name = "delete-expired-group-metadata",
fun = () => cleanupGroupMetadata(),
period = config.offsetsRetentionCheckIntervalMs,
unit = TimeUnit.MILLISECONDS)
}
}
def currentGroups: Iterable[GroupMetadata] = groupMetadataCache.values
def isPartitionOwned(partition: Int) = inLock(partitionLock) { ownedPartitions.contains(partition) }
def isPartitionLoading(partition: Int) = inLock(partitionLock) { loadingPartitions.contains(partition) }
def partitionFor(groupId: String): Int = Utils.abs(groupId.hashCode) % groupMetadataTopicPartitionCount
def isGroupLocal(groupId: String): Boolean = isPartitionOwned(partitionFor(groupId))
def isGroupLoading(groupId: String): Boolean = isPartitionLoading(partitionFor(groupId))
def isLoading: Boolean = inLock(partitionLock) { loadingPartitions.nonEmpty }
// return true iff group is owned and the group doesn't exist
def groupNotExists(groupId: String) = inLock(partitionLock) {
isGroupLocal(groupId) && getGroup(groupId).forall { group =>
group.inLock(group.is(Dead))
}
}
// visible for testing
private[group] def isGroupOpenForProducer(producerId: Long, groupId: String) = openGroupsForProducer.get(producerId) match {
case Some(groups) =>
groups.contains(groupId)
case None =>
false
}
/**
* Get the group associated with the given groupId or null if not found
*/
def getGroup(groupId: String): Option[GroupMetadata] = {
Option(groupMetadataCache.get(groupId))
}
/**
* Get the group associated with the given groupId - the group is created if createIfNotExist
* is true - or null if not found
*/
def getOrMaybeCreateGroup(groupId: String, createIfNotExist: Boolean): Option[GroupMetadata] = {
if (createIfNotExist)
Option(groupMetadataCache.getAndMaybePut(groupId, new GroupMetadata(groupId, Empty, time)))
else
Option(groupMetadataCache.get(groupId))
}
/**
* Add a group or get the group associated with the given groupId if it already exists
*/
def addGroup(group: GroupMetadata): GroupMetadata = {
val currentGroup = groupMetadataCache.putIfNotExists(group.groupId, group)
if (currentGroup != null) {
currentGroup
} else {
group
}
}
def storeGroup(group: GroupMetadata,
groupAssignment: Map[String, Array[Byte]],
responseCallback: Errors => Unit): Unit = {
getMagic(partitionFor(group.groupId)) match {
case Some(magicValue) =>
// We always use CREATE_TIME, like the producer. The conversion to LOG_APPEND_TIME (if necessary) happens automatically.
val timestampType = TimestampType.CREATE_TIME
val timestamp = time.milliseconds()
val key = GroupMetadataManager.groupMetadataKey(group.groupId)
val value = GroupMetadataManager.groupMetadataValue(group, groupAssignment, interBrokerProtocolVersion)
val records = {
val buffer = ByteBuffer.allocate(AbstractRecords.estimateSizeInBytes(magicValue, compressionType,
Seq(new SimpleRecord(timestamp, key, value)).asJava))
val builder = MemoryRecords.builder(buffer, magicValue, compressionType, timestampType, 0L)
builder.append(timestamp, key, value)
builder.build()
}
val groupMetadataPartition = new TopicPartition(Topic.GROUP_METADATA_TOPIC_NAME, partitionFor(group.groupId))
val groupMetadataRecords = Map(groupMetadataPartition -> records)
val generationId = group.generationId
// set the callback function to insert the created group into cache after log append completed
def putCacheCallback(responseStatus: Map[TopicPartition, PartitionResponse]): Unit = {
// the append response should only contain the topics partition
if (responseStatus.size != 1 || !responseStatus.contains(groupMetadataPartition))
throw new IllegalStateException("Append status %s should only have one partition %s"
.format(responseStatus, groupMetadataPartition))
// construct the error status in the propagated assignment response in the cache
val status = responseStatus(groupMetadataPartition)
val responseError = if (status.error == Errors.NONE) {
Errors.NONE
} else {
debug(s"Metadata from group ${group.groupId} with generation $generationId failed when appending to log " +
s"due to ${status.error.exceptionName}")
// transform the log append error code to the corresponding the commit status error code
status.error match {
case Errors.UNKNOWN_TOPIC_OR_PARTITION
| Errors.NOT_ENOUGH_REPLICAS
| Errors.NOT_ENOUGH_REPLICAS_AFTER_APPEND =>
Errors.COORDINATOR_NOT_AVAILABLE
case Errors.NOT_LEADER_OR_FOLLOWER
| Errors.KAFKA_STORAGE_ERROR =>
Errors.NOT_COORDINATOR
case Errors.REQUEST_TIMED_OUT =>
Errors.REBALANCE_IN_PROGRESS
case Errors.MESSAGE_TOO_LARGE
| Errors.RECORD_LIST_TOO_LARGE
| Errors.INVALID_FETCH_SIZE =>
error(s"Appending metadata message for group ${group.groupId} generation $generationId failed due to " +
s"${status.error.exceptionName}, returning UNKNOWN error code to the client")
Errors.UNKNOWN_SERVER_ERROR
case other =>
error(s"Appending metadata message for group ${group.groupId} generation $generationId failed " +
s"due to unexpected error: ${status.error.exceptionName}")
other
}
}
responseCallback(responseError)
}
appendForGroup(group, groupMetadataRecords, putCacheCallback)
case None =>
responseCallback(Errors.NOT_COORDINATOR)
None
}
}
private def appendForGroup(group: GroupMetadata,
records: Map[TopicPartition, MemoryRecords],
callback: Map[TopicPartition, PartitionResponse] => Unit): Unit = {
// call replica manager to append the group message
replicaManager.appendRecords(
timeout = config.offsetCommitTimeoutMs.toLong,
requiredAcks = config.offsetCommitRequiredAcks,
internalTopicsAllowed = true,
origin = AppendOrigin.Coordinator,
entriesPerPartition = records,
delayedProduceLock = Some(group.lock),
responseCallback = callback)
}
/**
* Store offsets by appending it to the replicated log and then inserting to cache
*/
def storeOffsets(group: GroupMetadata,
consumerId: String,
offsetMetadata: immutable.Map[TopicPartition, OffsetAndMetadata],
responseCallback: immutable.Map[TopicPartition, Errors] => Unit,
producerId: Long = RecordBatch.NO_PRODUCER_ID,
producerEpoch: Short = RecordBatch.NO_PRODUCER_EPOCH): Unit = {
// first filter out partitions with offset metadata size exceeding limit
val filteredOffsetMetadata = offsetMetadata.filter { case (_, offsetAndMetadata) =>
validateOffsetMetadataLength(offsetAndMetadata.metadata)
}
group.inLock {
if (!group.hasReceivedConsistentOffsetCommits)
warn(s"group: ${group.groupId} with leader: ${group.leaderOrNull} has received offset commits from consumers as well " +
s"as transactional producers. Mixing both types of offset commits will generally result in surprises and " +
s"should be avoided.")
}
val isTxnOffsetCommit = producerId != RecordBatch.NO_PRODUCER_ID
// construct the message set to append
if (filteredOffsetMetadata.isEmpty) {
// compute the final error codes for the commit response
val commitStatus = offsetMetadata.map { case (k, _) => k -> Errors.OFFSET_METADATA_TOO_LARGE }
responseCallback(commitStatus)
None
} else {
getMagic(partitionFor(group.groupId)) match {
case Some(magicValue) =>
// We always use CREATE_TIME, like the producer. The conversion to LOG_APPEND_TIME (if necessary) happens automatically.
val timestampType = TimestampType.CREATE_TIME
val timestamp = time.milliseconds()
val records = filteredOffsetMetadata.map { case (topicPartition, offsetAndMetadata) =>
val key = GroupMetadataManager.offsetCommitKey(group.groupId, topicPartition)
val value = GroupMetadataManager.offsetCommitValue(offsetAndMetadata, interBrokerProtocolVersion)
new SimpleRecord(timestamp, key, value)
}
val offsetTopicPartition = new TopicPartition(Topic.GROUP_METADATA_TOPIC_NAME, partitionFor(group.groupId))
val buffer = ByteBuffer.allocate(AbstractRecords.estimateSizeInBytes(magicValue, compressionType, records.asJava))
if (isTxnOffsetCommit && magicValue < RecordBatch.MAGIC_VALUE_V2)
throw Errors.UNSUPPORTED_FOR_MESSAGE_FORMAT.exception("Attempting to make a transaction offset commit with an invalid magic: " + magicValue)
val builder = MemoryRecords.builder(buffer, magicValue, compressionType, timestampType, 0L, time.milliseconds(),
producerId, producerEpoch, 0, isTxnOffsetCommit, RecordBatch.NO_PARTITION_LEADER_EPOCH)
records.foreach(builder.append)
val entries = Map(offsetTopicPartition -> builder.build())
// set the callback function to insert offsets into cache after log append completed
def putCacheCallback(responseStatus: Map[TopicPartition, PartitionResponse]): Unit = {
// the append response should only contain the topics partition
if (responseStatus.size != 1 || !responseStatus.contains(offsetTopicPartition))
throw new IllegalStateException("Append status %s should only have one partition %s"
.format(responseStatus, offsetTopicPartition))
// record the number of offsets committed to the log
offsetCommitsSensor.record(records.size)
// construct the commit response status and insert
// the offset and metadata to cache if the append status has no error
val status = responseStatus(offsetTopicPartition)
val responseError = group.inLock {
if (status.error == Errors.NONE) {
if (!group.is(Dead)) {
filteredOffsetMetadata.foreach { case (topicPartition, offsetAndMetadata) =>
if (isTxnOffsetCommit)
group.onTxnOffsetCommitAppend(producerId, topicPartition, CommitRecordMetadataAndOffset(Some(status.baseOffset), offsetAndMetadata))
else
group.onOffsetCommitAppend(topicPartition, CommitRecordMetadataAndOffset(Some(status.baseOffset), offsetAndMetadata))
}
}
Errors.NONE
} else {
if (!group.is(Dead)) {
if (!group.hasPendingOffsetCommitsFromProducer(producerId))
removeProducerGroup(producerId, group.groupId)
filteredOffsetMetadata.foreach { case (topicPartition, offsetAndMetadata) =>
if (isTxnOffsetCommit)
group.failPendingTxnOffsetCommit(producerId, topicPartition)
else
group.failPendingOffsetWrite(topicPartition, offsetAndMetadata)
}
}
debug(s"Offset commit $filteredOffsetMetadata from group ${group.groupId}, consumer $consumerId " +
s"with generation ${group.generationId} failed when appending to log due to ${status.error.exceptionName}")
// transform the log append error code to the corresponding the commit status error code
status.error match {
case Errors.UNKNOWN_TOPIC_OR_PARTITION
| Errors.NOT_ENOUGH_REPLICAS
| Errors.NOT_ENOUGH_REPLICAS_AFTER_APPEND =>
Errors.COORDINATOR_NOT_AVAILABLE
case Errors.NOT_LEADER_OR_FOLLOWER
| Errors.KAFKA_STORAGE_ERROR =>
Errors.NOT_COORDINATOR
case Errors.MESSAGE_TOO_LARGE
| Errors.RECORD_LIST_TOO_LARGE
| Errors.INVALID_FETCH_SIZE =>
Errors.INVALID_COMMIT_OFFSET_SIZE
case other => other
}
}
}
// compute the final error codes for the commit response
val commitStatus = offsetMetadata.map { case (topicPartition, offsetAndMetadata) =>
if (validateOffsetMetadataLength(offsetAndMetadata.metadata))
(topicPartition, responseError)
else
(topicPartition, Errors.OFFSET_METADATA_TOO_LARGE)
}
// finally trigger the callback logic passed from the API layer
responseCallback(commitStatus)
}
if (isTxnOffsetCommit) {
group.inLock {
addProducerGroup(producerId, group.groupId)
group.prepareTxnOffsetCommit(producerId, offsetMetadata)
}
} else {
group.inLock {
group.prepareOffsetCommit(offsetMetadata)
}
}
appendForGroup(group, entries, putCacheCallback)
case None =>
val commitStatus = offsetMetadata.map { case (topicPartition, _) =>
(topicPartition, Errors.NOT_COORDINATOR)
}
responseCallback(commitStatus)
None
}
}
}
/**
* The most important guarantee that this API provides is that it should never return a stale offset. i.e., it either
* returns the current offset or it begins to sync the cache from the log (and returns an error code).
*/
def getOffsets(groupId: String, requireStable: Boolean, topicPartitionsOpt: Option[Seq[TopicPartition]]): Map[TopicPartition, PartitionData] = {
trace("Getting offsets of %s for group %s.".format(topicPartitionsOpt.getOrElse("all partitions"), groupId))
val group = groupMetadataCache.get(groupId)
if (group == null) {
topicPartitionsOpt.getOrElse(Seq.empty[TopicPartition]).map { topicPartition =>
val partitionData = new PartitionData(OffsetFetchResponse.INVALID_OFFSET,
Optional.empty(), "", Errors.NONE)
topicPartition -> partitionData
}.toMap
} else {
group.inLock {
if (group.is(Dead)) {
topicPartitionsOpt.getOrElse(Seq.empty[TopicPartition]).map { topicPartition =>
val partitionData = new PartitionData(OffsetFetchResponse.INVALID_OFFSET,
Optional.empty(), "", Errors.NONE)
topicPartition -> partitionData
}.toMap
} else {
val topicPartitions = topicPartitionsOpt.getOrElse(group.allOffsets.keySet)
topicPartitions.map { topicPartition =>
if (requireStable && group.hasPendingOffsetCommitsForTopicPartition(topicPartition)) {
topicPartition -> new PartitionData(OffsetFetchResponse.INVALID_OFFSET,
Optional.empty(), "", Errors.UNSTABLE_OFFSET_COMMIT)
} else {
val partitionData = group.offset(topicPartition) match {
case None =>
new PartitionData(OffsetFetchResponse.INVALID_OFFSET,
Optional.empty(), "", Errors.NONE)
case Some(offsetAndMetadata) =>
new PartitionData(offsetAndMetadata.offset,
offsetAndMetadata.leaderEpoch, offsetAndMetadata.metadata, Errors.NONE)
}
topicPartition -> partitionData
}
}.toMap
}
}
}
}
/**
* Asynchronously read the partition from the offsets topic and populate the cache
*/
def scheduleLoadGroupAndOffsets(offsetsPartition: Int, onGroupLoaded: GroupMetadata => Unit): Unit = {
val topicPartition = new TopicPartition(Topic.GROUP_METADATA_TOPIC_NAME, offsetsPartition)
if (addLoadingPartition(offsetsPartition)) {
info(s"Scheduling loading of offsets and group metadata from $topicPartition")
val startTimeMs = time.milliseconds()
scheduler.schedule(topicPartition.toString, () => loadGroupsAndOffsets(topicPartition, onGroupLoaded, startTimeMs))
} else {
info(s"Already loading offsets and group metadata from $topicPartition")
}
}
private[group] def loadGroupsAndOffsets(topicPartition: TopicPartition, onGroupLoaded: GroupMetadata => Unit, startTimeMs: java.lang.Long): Unit = {
try {
val schedulerTimeMs = time.milliseconds() - startTimeMs
doLoadGroupsAndOffsets(topicPartition, onGroupLoaded)
val endTimeMs = time.milliseconds()
val totalLoadingTimeMs = endTimeMs - startTimeMs
partitionLoadSensor.record(totalLoadingTimeMs.toDouble, endTimeMs, false)
info(s"Finished loading offsets and group metadata from $topicPartition "
+ s"in $totalLoadingTimeMs milliseconds, of which $schedulerTimeMs milliseconds"
+ s" was spent in the scheduler.")
} catch {
case t: Throwable => error(s"Error loading offsets from $topicPartition", t)
} finally {
inLock(partitionLock) {
ownedPartitions.add(topicPartition.partition)
loadingPartitions.remove(topicPartition.partition)
}
}
}
private def doLoadGroupsAndOffsets(topicPartition: TopicPartition, onGroupLoaded: GroupMetadata => Unit): Unit = {
def logEndOffset: Long = replicaManager.getLogEndOffset(topicPartition).getOrElse(-1L)
replicaManager.getLog(topicPartition) match {
case None =>
warn(s"Attempted to load offsets and group metadata from $topicPartition, but found no log")
case Some(log) =>
val loadedOffsets = mutable.Map[GroupTopicPartition, CommitRecordMetadataAndOffset]()
val pendingOffsets = mutable.Map[Long, mutable.Map[GroupTopicPartition, CommitRecordMetadataAndOffset]]()
val loadedGroups = mutable.Map[String, GroupMetadata]()
val removedGroups = mutable.Set[String]()
// buffer may not be needed if records are read from memory
var buffer = ByteBuffer.allocate(0)
// loop breaks if leader changes at any time during the load, since logEndOffset is -1
var currOffset = log.logStartOffset
// loop breaks if no records have been read, since the end of the log has been reached
var readAtLeastOneRecord = true
while (currOffset < logEndOffset && readAtLeastOneRecord && !shuttingDown.get()) {
val fetchDataInfo = log.read(currOffset,
maxLength = config.loadBufferSize,
isolation = FetchLogEnd,
minOneMessage = true)
readAtLeastOneRecord = fetchDataInfo.records.sizeInBytes > 0
val memRecords = fetchDataInfo.records match {
case records: MemoryRecords => records
case fileRecords: FileRecords =>
val sizeInBytes = fileRecords.sizeInBytes
val bytesNeeded = Math.max(config.loadBufferSize, sizeInBytes)
// minOneMessage = true in the above log.read means that the buffer may need to be grown to ensure progress can be made
if (buffer.capacity < bytesNeeded) {
if (config.loadBufferSize < bytesNeeded)
warn(s"Loaded offsets and group metadata from $topicPartition with buffer larger ($bytesNeeded bytes) than " +
s"configured offsets.load.buffer.size (${config.loadBufferSize} bytes)")
buffer = ByteBuffer.allocate(bytesNeeded)
} else {
buffer.clear()
}
fileRecords.readInto(buffer, 0)
MemoryRecords.readableRecords(buffer)
}
memRecords.batches.forEach { batch =>
val isTxnOffsetCommit = batch.isTransactional
if (batch.isControlBatch) {
val recordIterator = batch.iterator
if (recordIterator.hasNext) {
val record = recordIterator.next()
val controlRecord = ControlRecordType.parse(record.key)
if (controlRecord == ControlRecordType.COMMIT) {
pendingOffsets.getOrElse(batch.producerId, mutable.Map[GroupTopicPartition, CommitRecordMetadataAndOffset]())
.foreach {
case (groupTopicPartition, commitRecordMetadataAndOffset) =>
if (!loadedOffsets.contains(groupTopicPartition) || loadedOffsets(groupTopicPartition).olderThan(commitRecordMetadataAndOffset))
loadedOffsets.put(groupTopicPartition, commitRecordMetadataAndOffset)
}
}
pendingOffsets.remove(batch.producerId)
}
} else {
var batchBaseOffset: Option[Long] = None
for (record <- batch.asScala) {
require(record.hasKey, "Group metadata/offset entry key should not be null")
if (batchBaseOffset.isEmpty)
batchBaseOffset = Some(record.offset)
GroupMetadataManager.readMessageKey(record.key) match {
case offsetKey: OffsetKey =>
if (isTxnOffsetCommit && !pendingOffsets.contains(batch.producerId))
pendingOffsets.put(batch.producerId, mutable.Map[GroupTopicPartition, CommitRecordMetadataAndOffset]())
// load offset
val groupTopicPartition = offsetKey.key
if (!record.hasValue) {
if (isTxnOffsetCommit)
pendingOffsets(batch.producerId).remove(groupTopicPartition)
else
loadedOffsets.remove(groupTopicPartition)
} else {
val offsetAndMetadata = GroupMetadataManager.readOffsetMessageValue(record.value)
if (isTxnOffsetCommit)
pendingOffsets(batch.producerId).put(groupTopicPartition, CommitRecordMetadataAndOffset(batchBaseOffset, offsetAndMetadata))
else
loadedOffsets.put(groupTopicPartition, CommitRecordMetadataAndOffset(batchBaseOffset, offsetAndMetadata))
}
case groupMetadataKey: GroupMetadataKey =>
// load group metadata
val groupId = groupMetadataKey.key
val groupMetadata = GroupMetadataManager.readGroupMessageValue(groupId, record.value, time)
if (groupMetadata != null) {
removedGroups.remove(groupId)
loadedGroups.put(groupId, groupMetadata)
} else {
loadedGroups.remove(groupId)
removedGroups.add(groupId)
}
case unknownKey =>
throw new IllegalStateException(s"Unexpected message key $unknownKey while loading offsets and group metadata")
}
}
}
currOffset = batch.nextOffset
}
}
val (groupOffsets, emptyGroupOffsets) = loadedOffsets
.groupBy(_._1.group)
.map { case (k, v) =>
k -> v.map { case (groupTopicPartition, offset) => (groupTopicPartition.topicPartition, offset) }
}.partition { case (group, _) => loadedGroups.contains(group) }
val pendingOffsetsByGroup = mutable.Map[String, mutable.Map[Long, mutable.Map[TopicPartition, CommitRecordMetadataAndOffset]]]()
pendingOffsets.foreach { case (producerId, producerOffsets) =>
producerOffsets.keySet.map(_.group).foreach(addProducerGroup(producerId, _))
producerOffsets
.groupBy(_._1.group)
.foreach { case (group, offsets) =>
val groupPendingOffsets = pendingOffsetsByGroup.getOrElseUpdate(group, mutable.Map.empty[Long, mutable.Map[TopicPartition, CommitRecordMetadataAndOffset]])
val groupProducerOffsets = groupPendingOffsets.getOrElseUpdate(producerId, mutable.Map.empty[TopicPartition, CommitRecordMetadataAndOffset])
groupProducerOffsets ++= offsets.map { case (groupTopicPartition, offset) =>
(groupTopicPartition.topicPartition, offset)
}
}
}
val (pendingGroupOffsets, pendingEmptyGroupOffsets) = pendingOffsetsByGroup
.partition { case (group, _) => loadedGroups.contains(group)}
loadedGroups.values.foreach { group =>
val offsets = groupOffsets.getOrElse(group.groupId, Map.empty[TopicPartition, CommitRecordMetadataAndOffset])
val pendingOffsets = pendingGroupOffsets.getOrElse(group.groupId, Map.empty[Long, mutable.Map[TopicPartition, CommitRecordMetadataAndOffset]])
debug(s"Loaded group metadata $group with offsets $offsets and pending offsets $pendingOffsets")
loadGroup(group, offsets, pendingOffsets)
onGroupLoaded(group)
}
// load groups which store offsets in kafka, but which have no active members and thus no group
// metadata stored in the log
(emptyGroupOffsets.keySet ++ pendingEmptyGroupOffsets.keySet).foreach { groupId =>
val group = new GroupMetadata(groupId, Empty, time)
val offsets = emptyGroupOffsets.getOrElse(groupId, Map.empty[TopicPartition, CommitRecordMetadataAndOffset])
val pendingOffsets = pendingEmptyGroupOffsets.getOrElse(groupId, Map.empty[Long, mutable.Map[TopicPartition, CommitRecordMetadataAndOffset]])
debug(s"Loaded group metadata $group with offsets $offsets and pending offsets $pendingOffsets")
loadGroup(group, offsets, pendingOffsets)
onGroupLoaded(group)
}
removedGroups.foreach { groupId =>
// if the cache already contains a group which should be removed, raise an error. Note that it
// is possible (however unlikely) for a consumer group to be removed, and then to be used only for
// offset storage (i.e. by "simple" consumers)
if (groupMetadataCache.contains(groupId) && !emptyGroupOffsets.contains(groupId))
throw new IllegalStateException(s"Unexpected unload of active group $groupId while " +
s"loading partition $topicPartition")
}
}
}
private def loadGroup(group: GroupMetadata, offsets: Map[TopicPartition, CommitRecordMetadataAndOffset],
pendingTransactionalOffsets: Map[Long, mutable.Map[TopicPartition, CommitRecordMetadataAndOffset]]): Unit = {
// offsets are initialized prior to loading the group into the cache to ensure that clients see a consistent
// view of the group's offsets
trace(s"Initialized offsets $offsets for group ${group.groupId}")
group.initializeOffsets(offsets, pendingTransactionalOffsets.toMap)
val currentGroup = addGroup(group)
if (group != currentGroup)
debug(s"Attempt to load group ${group.groupId} from log with generation ${group.generationId} failed " +
s"because there is already a cached group with generation ${currentGroup.generationId}")
}
/**
* When this broker becomes a follower for an offsets topic partition clear out the cache for groups that belong to
* that partition.
*
* @param offsetsPartition Groups belonging to this partition of the offsets topic will be deleted from the cache.
*/
def removeGroupsForPartition(offsetsPartition: Int,
onGroupUnloaded: GroupMetadata => Unit): Unit = {
val topicPartition = new TopicPartition(Topic.GROUP_METADATA_TOPIC_NAME, offsetsPartition)
info(s"Scheduling unloading of offsets and group metadata from $topicPartition")
scheduler.schedule(topicPartition.toString, () => removeGroupsAndOffsets())
def removeGroupsAndOffsets(): Unit = {
var numOffsetsRemoved = 0
var numGroupsRemoved = 0
inLock(partitionLock) {
// we need to guard the group removal in cache in the loading partition lock
// to prevent coordinator's check-and-get-group race condition
ownedPartitions.remove(offsetsPartition)
for (group <- groupMetadataCache.values) {
if (partitionFor(group.groupId) == offsetsPartition) {
onGroupUnloaded(group)
groupMetadataCache.remove(group.groupId, group)
removeGroupFromAllProducers(group.groupId)
numGroupsRemoved += 1
numOffsetsRemoved += group.numOffsets
}
}
}
info(s"Finished unloading $topicPartition. Removed $numOffsetsRemoved cached offsets " +
s"and $numGroupsRemoved cached groups.")
}
}
// visible for testing
private[group] def cleanupGroupMetadata(): Unit = {
val currentTimestamp = time.milliseconds()
val numOffsetsRemoved = cleanupGroupMetadata(groupMetadataCache.values, group => {
group.removeExpiredOffsets(currentTimestamp, config.offsetsRetentionMs)
})
offsetExpiredSensor.record(numOffsetsRemoved)
if (numOffsetsRemoved > 0)
info(s"Removed $numOffsetsRemoved expired offsets in ${time.milliseconds() - currentTimestamp} milliseconds.")
}
/**
* This function is used to clean up group offsets given the groups and also a function that performs the offset deletion.
* @param groups Groups whose metadata are to be cleaned up
* @param selector A function that implements deletion of (all or part of) group offsets. This function is called while
* a group lock is held, therefore there is no need for the caller to also obtain a group lock.
* @return The cumulative number of offsets removed
*/
def cleanupGroupMetadata(groups: Iterable[GroupMetadata], selector: GroupMetadata => Map[TopicPartition, OffsetAndMetadata]): Int = {
var offsetsRemoved = 0
groups.foreach { group =>
val groupId = group.groupId
val (removedOffsets, groupIsDead, generation) = group.inLock {
val removedOffsets = selector(group)
if (group.is(Empty) && !group.hasOffsets) {
info(s"Group $groupId transitioned to Dead in generation ${group.generationId}")
group.transitionTo(Dead)
}
(removedOffsets, group.is(Dead), group.generationId)
}
val offsetsPartition = partitionFor(groupId)
val appendPartition = new TopicPartition(Topic.GROUP_METADATA_TOPIC_NAME, offsetsPartition)
getMagic(offsetsPartition) match {
case Some(magicValue) =>
// We always use CREATE_TIME, like the producer. The conversion to LOG_APPEND_TIME (if necessary) happens automatically.
val timestampType = TimestampType.CREATE_TIME
val timestamp = time.milliseconds()
replicaManager.nonOfflinePartition(appendPartition).foreach { partition =>
val tombstones = ArrayBuffer.empty[SimpleRecord]
removedOffsets.foreach { case (topicPartition, offsetAndMetadata) =>
trace(s"Removing expired/deleted offset and metadata for $groupId, $topicPartition: $offsetAndMetadata")
val commitKey = GroupMetadataManager.offsetCommitKey(groupId, topicPartition)
tombstones += new SimpleRecord(timestamp, commitKey, null)
}
trace(s"Marked ${removedOffsets.size} offsets in $appendPartition for deletion.")
// We avoid writing the tombstone when the generationId is 0, since this group is only using
// Kafka for offset storage.
if (groupIsDead && groupMetadataCache.remove(groupId, group) && generation > 0) {
// Append the tombstone messages to the partition. It is okay if the replicas don't receive these (say,
// if we crash or leaders move) since the new leaders will still expire the consumers with heartbeat and
// retry removing this group.
val groupMetadataKey = GroupMetadataManager.groupMetadataKey(group.groupId)
tombstones += new SimpleRecord(timestamp, groupMetadataKey, null)
trace(s"Group $groupId removed from the metadata cache and marked for deletion in $appendPartition.")
}
if (tombstones.nonEmpty) {
try {
// do not need to require acks since even if the tombstone is lost,
// it will be appended again in the next purge cycle
val records = MemoryRecords.withRecords(magicValue, 0L, compressionType, timestampType, tombstones.toArray: _*)
partition.appendRecordsToLeader(records, origin = AppendOrigin.Coordinator, requiredAcks = 0)
offsetsRemoved += removedOffsets.size
trace(s"Successfully appended ${tombstones.size} tombstones to $appendPartition for expired/deleted " +
s"offsets and/or metadata for group $groupId")
} catch {
case t: Throwable =>
error(s"Failed to append ${tombstones.size} tombstones to $appendPartition for expired/deleted " +
s"offsets and/or metadata for group $groupId.", t)
// ignore and continue
}
}
}
case None =>
info(s"BrokerId $brokerId is no longer a coordinator for the group $groupId. Proceeding cleanup for other alive groups")
}
}
offsetsRemoved
}
/**
* Complete pending transactional offset commits of the groups of `producerId` from the provided
* `completedPartitions`. This method is invoked when a commit or abort marker is fully written
* to the log. It may be invoked when a group lock is held by the caller, for instance when delayed
* operations are completed while appending offsets for a group. Since we need to acquire one or
* more group metadata locks to handle transaction completion, this operation is scheduled on
* the scheduler thread to avoid deadlocks.
*/
def scheduleHandleTxnCompletion(producerId: Long, completedPartitions: Set[Int], isCommit: Boolean): Unit = {
scheduler.schedule(s"handleTxnCompletion-$producerId", () =>
handleTxnCompletion(producerId, completedPartitions, isCommit))
}
private[group] def handleTxnCompletion(producerId: Long, completedPartitions: Set[Int], isCommit: Boolean): Unit = {
val pendingGroups = groupsBelongingToPartitions(producerId, completedPartitions)
pendingGroups.foreach { groupId =>
getGroup(groupId) match {
case Some(group) => group.inLock {
if (!group.is(Dead)) {
group.completePendingTxnOffsetCommit(producerId, isCommit)
removeProducerGroup(producerId, groupId)
}
}
case _ =>
info(s"Group $groupId has moved away from $brokerId after transaction marker was written but before the " +
s"cache was updated. The cache on the new group owner will be updated instead.")
}
}
}
private def addProducerGroup(producerId: Long, groupId: String) = openGroupsForProducer synchronized {
openGroupsForProducer.getOrElseUpdate(producerId, mutable.Set.empty[String]).add(groupId)
}
private def removeProducerGroup(producerId: Long, groupId: String) = openGroupsForProducer synchronized {
openGroupsForProducer.getOrElseUpdate(producerId, mutable.Set.empty[String]).remove(groupId)
if (openGroupsForProducer(producerId).isEmpty)
openGroupsForProducer.remove(producerId)
}
private def groupsBelongingToPartitions(producerId: Long, partitions: Set[Int]) = openGroupsForProducer synchronized {
val (ownedGroups, _) = openGroupsForProducer.getOrElse(producerId, mutable.Set.empty[String])
.partition { case (group) => partitions.contains(partitionFor(group)) }
ownedGroups
}
private def removeGroupFromAllProducers(groupId: String) = openGroupsForProducer synchronized {
openGroupsForProducer.foreach { case (_, groups) =>
groups.remove(groupId)
}
}
/*
* Check if the offset metadata length is valid
*/
private def validateOffsetMetadataLength(metadata: String) : Boolean = {
metadata == null || metadata.length() <= config.maxMetadataSize
}
def shutdown(): Unit = {
shuttingDown.set(true)
if (scheduler.isStarted)
scheduler.shutdown()
// TODO: clear the caches
}
/**
* Gets the partition count of the group metadata topic from ZooKeeper.
* If the topic does not exist, the configured partition count is returned.
*/
private def getGroupMetadataTopicPartitionCount: Int = {
zkClient.getTopicPartitionCount(Topic.GROUP_METADATA_TOPIC_NAME).getOrElse(config.offsetsTopicNumPartitions)
}
/**
* Check if the replica is local and return the message format version and timestamp
*
* @param partition Partition of GroupMetadataTopic
* @return Some(MessageFormatVersion) if replica is local, None otherwise
*/
private def getMagic(partition: Int): Option[Byte] =
replicaManager.getMagic(new TopicPartition(Topic.GROUP_METADATA_TOPIC_NAME, partition))
/**
* Add the partition into the owned list
*
* NOTE: this is for test only
*/
private[group] def addPartitionOwnership(partition: Int): Unit = {
inLock(partitionLock) {
ownedPartitions.add(partition)
}
}
/**
* Add a partition to the loading partitions set. Return true if the partition was not
* already loading.
*
* Visible for testing
*/
private[group] def addLoadingPartition(partition: Int): Boolean = {
inLock(partitionLock) {
loadingPartitions.add(partition)
}
}
}
/**
* Messages stored for the group topic has versions for both the key and value fields. Key
* version is used to indicate the type of the message (also to differentiate different types
* of messages from being compacted together if they have the same field values); and value
* version is used to evolve the messages within their data types:
*
* key version 0: group consumption offset
* -> value version 0: [offset, metadata, timestamp]
*
* key version 1: group consumption offset
* -> value version 1: [offset, metadata, commit_timestamp, expire_timestamp]
*
* key version 2: group metadata
* -> value version 0: [protocol_type, generation, protocol, leader, members]
*/
object GroupMetadataManager {
// Metrics names
val MetricsGroup: String = "group-coordinator-metrics"
val LoadTimeSensor: String = "GroupPartitionLoadTime"
private val CURRENT_OFFSET_KEY_SCHEMA_VERSION = 1.toShort
private val CURRENT_GROUP_KEY_SCHEMA_VERSION = 2.toShort