kafka Metadata 源码
kafka Metadata 代码
文件路径：/clients/src/main/java/org/apache/kafka/clients/Metadata.java
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* 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
*
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package org.apache.kafka.clients;
import org.apache.kafka.common.Cluster;
import org.apache.kafka.common.KafkaException;
import org.apache.kafka.common.Node;
import org.apache.kafka.common.TopicPartition;
import org.apache.kafka.common.Uuid;
import org.apache.kafka.common.errors.InvalidMetadataException;
import org.apache.kafka.common.errors.InvalidTopicException;
import org.apache.kafka.common.errors.TopicAuthorizationException;
import org.apache.kafka.common.internals.ClusterResourceListeners;
import org.apache.kafka.common.protocol.Errors;
import org.apache.kafka.common.requests.MetadataRequest;
import org.apache.kafka.common.requests.MetadataResponse;
import org.apache.kafka.common.utils.LogContext;
import org.slf4j.Logger;
import java.io.Closeable;
import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
import java.util.function.Supplier;
import static org.apache.kafka.common.record.RecordBatch.NO_PARTITION_LEADER_EPOCH;
/**
* A class encapsulating some of the logic around metadata.
* <p>
* This class is shared by the client thread (for partitioning) and the background sender thread.
*
* Metadata is maintained for only a subset of topics, which can be added to over time. When we request metadata for a
* topic we don't have any metadata for it will trigger a metadata update.
* <p>
* If topic expiry is enabled for the metadata, any topic that has not been used within the expiry interval
* is removed from the metadata refresh set after an update. Consumers disable topic expiry since they explicitly
* manage topics while producers rely on topic expiry to limit the refresh set.
*/
public class Metadata implements Closeable {
private final Logger log;
private final long refreshBackoffMs;
private final long metadataExpireMs;
private int updateVersion; // bumped on every metadata response
private int requestVersion; // bumped on every new topic addition
private long lastRefreshMs;
private long lastSuccessfulRefreshMs;
private KafkaException fatalException;
private Set<String> invalidTopics;
private Set<String> unauthorizedTopics;
private MetadataCache cache = MetadataCache.empty();
private boolean needFullUpdate;
private boolean needPartialUpdate;
private final ClusterResourceListeners clusterResourceListeners;
private boolean isClosed;
private final Map<TopicPartition, Integer> lastSeenLeaderEpochs;
/**
* Create a new Metadata instance
*
* @param refreshBackoffMs The minimum amount of time that must expire between metadata refreshes to avoid busy
* polling
* @param metadataExpireMs The maximum amount of time that metadata can be retained without refresh
* @param logContext Log context corresponding to the containing client
* @param clusterResourceListeners List of ClusterResourceListeners which will receive metadata updates.
*/
public Metadata(long refreshBackoffMs,
long metadataExpireMs,
LogContext logContext,
ClusterResourceListeners clusterResourceListeners) {
this.log = logContext.logger(Metadata.class);
this.refreshBackoffMs = refreshBackoffMs;
this.metadataExpireMs = metadataExpireMs;
this.lastRefreshMs = 0L;
this.lastSuccessfulRefreshMs = 0L;
this.requestVersion = 0;
this.updateVersion = 0;
this.needFullUpdate = false;
this.needPartialUpdate = false;
this.clusterResourceListeners = clusterResourceListeners;
this.isClosed = false;
this.lastSeenLeaderEpochs = new HashMap<>();
this.invalidTopics = Collections.emptySet();
this.unauthorizedTopics = Collections.emptySet();
}
/**
* Get the current cluster info without blocking
*/
public synchronized Cluster fetch() {
return cache.cluster();
}
/**
* Return the next time when the current cluster info can be updated (i.e., backoff time has elapsed).
*
* @param nowMs current time in ms
* @return remaining time in ms till the cluster info can be updated again
*/
public synchronized long timeToAllowUpdate(long nowMs) {
return Math.max(this.lastRefreshMs + this.refreshBackoffMs - nowMs, 0);
}
/**
* The next time to update the cluster info is the maximum of the time the current info will expire and the time the
* current info can be updated (i.e. backoff time has elapsed); If an update has been request then the expiry time
* is now
*
* @param nowMs current time in ms
* @return remaining time in ms till updating the cluster info
*/
public synchronized long timeToNextUpdate(long nowMs) {
long timeToExpire = updateRequested() ? 0 : Math.max(this.lastSuccessfulRefreshMs + this.metadataExpireMs - nowMs, 0);
return Math.max(timeToExpire, timeToAllowUpdate(nowMs));
}
public long metadataExpireMs() {
return this.metadataExpireMs;
}
/**
* Request an update of the current cluster metadata info, return the current updateVersion before the update
*/
public synchronized int requestUpdate() {
this.needFullUpdate = true;
return this.updateVersion;
}
public synchronized int requestUpdateForNewTopics() {
// Override the timestamp of last refresh to let immediate update.
this.lastRefreshMs = 0;
this.needPartialUpdate = true;
this.requestVersion++;
return this.updateVersion;
}
/**
* Request an update for the partition metadata iff we have seen a newer leader epoch. This is called by the client
* any time it handles a response from the broker that includes leader epoch, except for UpdateMetadata which
* follows a different code path ({@link #update}).
*
* @param topicPartition
* @param leaderEpoch
* @return true if we updated the last seen epoch, false otherwise
*/
public synchronized boolean updateLastSeenEpochIfNewer(TopicPartition topicPartition, int leaderEpoch) {
Objects.requireNonNull(topicPartition, "TopicPartition cannot be null");
if (leaderEpoch < 0)
throw new IllegalArgumentException("Invalid leader epoch " + leaderEpoch + " (must be non-negative)");
Integer oldEpoch = lastSeenLeaderEpochs.get(topicPartition);
log.trace("Determining if we should replace existing epoch {} with new epoch {} for partition {}", oldEpoch, leaderEpoch, topicPartition);
final boolean updated;
if (oldEpoch == null) {
log.debug("Not replacing null epoch with new epoch {} for partition {}", leaderEpoch, topicPartition);
updated = false;
} else if (leaderEpoch > oldEpoch) {
log.debug("Updating last seen epoch from {} to {} for partition {}", oldEpoch, leaderEpoch, topicPartition);
lastSeenLeaderEpochs.put(topicPartition, leaderEpoch);
updated = true;
} else {
log.debug("Not replacing existing epoch {} with new epoch {} for partition {}", oldEpoch, leaderEpoch, topicPartition);
updated = false;
}
this.needFullUpdate = this.needFullUpdate || updated;
return updated;
}
public Optional<Integer> lastSeenLeaderEpoch(TopicPartition topicPartition) {
return Optional.ofNullable(lastSeenLeaderEpochs.get(topicPartition));
}
/**
* Check whether an update has been explicitly requested.
*
* @return true if an update was requested, false otherwise
*/
public synchronized boolean updateRequested() {
return this.needFullUpdate || this.needPartialUpdate;
}
/**
* Return the cached partition info if it exists and a newer leader epoch isn't known about.
*/
synchronized Optional<MetadataResponse.PartitionMetadata> partitionMetadataIfCurrent(TopicPartition topicPartition) {
Integer epoch = lastSeenLeaderEpochs.get(topicPartition);
Optional<MetadataResponse.PartitionMetadata> partitionMetadata = cache.partitionMetadata(topicPartition);
if (epoch == null) {
// old cluster format (no epochs)
return partitionMetadata;
} else {
return partitionMetadata.filter(metadata ->
metadata.leaderEpoch.orElse(NO_PARTITION_LEADER_EPOCH).equals(epoch));
}
}
/**
* @return a mapping from topic names to topic IDs for all topics with valid IDs in the cache
*/
public synchronized Map<String, Uuid> topicIds() {
return cache.topicIds();
}
public synchronized LeaderAndEpoch currentLeader(TopicPartition topicPartition) {
Optional<MetadataResponse.PartitionMetadata> maybeMetadata = partitionMetadataIfCurrent(topicPartition);
if (!maybeMetadata.isPresent())
return new LeaderAndEpoch(Optional.empty(), Optional.ofNullable(lastSeenLeaderEpochs.get(topicPartition)));
MetadataResponse.PartitionMetadata partitionMetadata = maybeMetadata.get();
Optional<Integer> leaderEpochOpt = partitionMetadata.leaderEpoch;
Optional<Node> leaderNodeOpt = partitionMetadata.leaderId.flatMap(cache::nodeById);
return new LeaderAndEpoch(leaderNodeOpt, leaderEpochOpt);
}
public synchronized void bootstrap(List<InetSocketAddress> addresses) {
this.needFullUpdate = true;
this.updateVersion += 1;
this.cache = MetadataCache.bootstrap(addresses);
}
/**
* Update metadata assuming the current request version.
*
* For testing only.
*/
public synchronized void updateWithCurrentRequestVersion(MetadataResponse response, boolean isPartialUpdate, long nowMs) {
this.update(this.requestVersion, response, isPartialUpdate, nowMs);
}
/**
* Updates the cluster metadata. If topic expiry is enabled, expiry time
* is set for topics if required and expired topics are removed from the metadata.
*
* @param requestVersion The request version corresponding to the update response, as provided by
* {@link #newMetadataRequestAndVersion(long)}.
* @param response metadata response received from the broker
* @param isPartialUpdate whether the metadata request was for a subset of the active topics
* @param nowMs current time in milliseconds
*/
public synchronized void update(int requestVersion, MetadataResponse response, boolean isPartialUpdate, long nowMs) {
Objects.requireNonNull(response, "Metadata response cannot be null");
if (isClosed())
throw new IllegalStateException("Update requested after metadata close");
this.needPartialUpdate = requestVersion < this.requestVersion;
this.lastRefreshMs = nowMs;
this.updateVersion += 1;
if (!isPartialUpdate) {
this.needFullUpdate = false;
this.lastSuccessfulRefreshMs = nowMs;
}
String previousClusterId = cache.clusterResource().clusterId();
this.cache = handleMetadataResponse(response, isPartialUpdate, nowMs);
Cluster cluster = cache.cluster();
maybeSetMetadataError(cluster);
this.lastSeenLeaderEpochs.keySet().removeIf(tp -> !retainTopic(tp.topic(), false, nowMs));
String newClusterId = cache.clusterResource().clusterId();
if (!Objects.equals(previousClusterId, newClusterId)) {
log.info("Cluster ID: {}", newClusterId);
}
clusterResourceListeners.onUpdate(cache.clusterResource());
log.debug("Updated cluster metadata updateVersion {} to {}", this.updateVersion, this.cache);
}
private void maybeSetMetadataError(Cluster cluster) {
clearRecoverableErrors();
checkInvalidTopics(cluster);
checkUnauthorizedTopics(cluster);
}
private void checkInvalidTopics(Cluster cluster) {
if (!cluster.invalidTopics().isEmpty()) {
log.error("Metadata response reported invalid topics {}", cluster.invalidTopics());
invalidTopics = new HashSet<>(cluster.invalidTopics());
}
}
private void checkUnauthorizedTopics(Cluster cluster) {
if (!cluster.unauthorizedTopics().isEmpty()) {
log.error("Topic authorization failed for topics {}", cluster.unauthorizedTopics());
unauthorizedTopics = new HashSet<>(cluster.unauthorizedTopics());
}
}
/**
* Transform a MetadataResponse into a new MetadataCache instance.
*/
private MetadataCache handleMetadataResponse(MetadataResponse metadataResponse, boolean isPartialUpdate, long nowMs) {
// All encountered topics.
Set<String> topics = new HashSet<>();
// Retained topics to be passed to the metadata cache.
Set<String> internalTopics = new HashSet<>();
Set<String> unauthorizedTopics = new HashSet<>();
Set<String> invalidTopics = new HashSet<>();
List<MetadataResponse.PartitionMetadata> partitions = new ArrayList<>();
Map<String, Uuid> topicIds = new HashMap<>();
Map<String, Uuid> oldTopicIds = cache.topicIds();
for (MetadataResponse.TopicMetadata metadata : metadataResponse.topicMetadata()) {
String topicName = metadata.topic();
Uuid topicId = metadata.topicId();
topics.add(topicName);
// We can only reason about topic ID changes when both IDs are valid, so keep oldId null unless the new metadata contains a topic ID
Uuid oldTopicId = null;
if (!Uuid.ZERO_UUID.equals(topicId)) {
topicIds.put(topicName, topicId);
oldTopicId = oldTopicIds.get(topicName);
} else {
topicId = null;
}
if (!retainTopic(topicName, metadata.isInternal(), nowMs))
continue;
if (metadata.isInternal())
internalTopics.add(topicName);
if (metadata.error() == Errors.NONE) {
for (MetadataResponse.PartitionMetadata partitionMetadata : metadata.partitionMetadata()) {
// Even if the partition's metadata includes an error, we need to handle
// the update to catch new epochs
updateLatestMetadata(partitionMetadata, metadataResponse.hasReliableLeaderEpochs(), topicId, oldTopicId)
.ifPresent(partitions::add);
if (partitionMetadata.error.exception() instanceof InvalidMetadataException) {
log.debug("Requesting metadata update for partition {} due to error {}",
partitionMetadata.topicPartition, partitionMetadata.error);
requestUpdate();
}
}
} else {
if (metadata.error().exception() instanceof InvalidMetadataException) {
log.debug("Requesting metadata update for topic {} due to error {}", topicName, metadata.error());
requestUpdate();
}
if (metadata.error() == Errors.INVALID_TOPIC_EXCEPTION)
invalidTopics.add(topicName);
else if (metadata.error() == Errors.TOPIC_AUTHORIZATION_FAILED)
unauthorizedTopics.add(topicName);
}
}
Map<Integer, Node> nodes = metadataResponse.brokersById();
if (isPartialUpdate)
return this.cache.mergeWith(metadataResponse.clusterId(), nodes, partitions,
unauthorizedTopics, invalidTopics, internalTopics, metadataResponse.controller(), topicIds,
(topic, isInternal) -> !topics.contains(topic) && retainTopic(topic, isInternal, nowMs));
else
return new MetadataCache(metadataResponse.clusterId(), nodes, partitions,
unauthorizedTopics, invalidTopics, internalTopics, metadataResponse.controller(), topicIds);
}
/**
* Compute the latest partition metadata to cache given ordering by leader epochs (if both
* available and reliable) and whether the topic ID changed.
*/
private Optional<MetadataResponse.PartitionMetadata> updateLatestMetadata(
MetadataResponse.PartitionMetadata partitionMetadata,
boolean hasReliableLeaderEpoch,
Uuid topicId,
Uuid oldTopicId) {
TopicPartition tp = partitionMetadata.topicPartition;
if (hasReliableLeaderEpoch && partitionMetadata.leaderEpoch.isPresent()) {
int newEpoch = partitionMetadata.leaderEpoch.get();
Integer currentEpoch = lastSeenLeaderEpochs.get(tp);
if (topicId != null && !topicId.equals(oldTopicId)) {
// If the new topic ID is valid and different from the last seen topic ID, update the metadata.
// Between the time that a topic is deleted and re-created, the client may lose track of the
// corresponding topicId (i.e. `oldTopicId` will be null). In this case, when we discover the new
// topicId, we allow the corresponding leader epoch to override the last seen value.
log.info("Resetting the last seen epoch of partition {} to {} since the associated topicId changed from {} to {}",
tp, newEpoch, oldTopicId, topicId);
lastSeenLeaderEpochs.put(tp, newEpoch);
return Optional.of(partitionMetadata);
} else if (currentEpoch == null || newEpoch >= currentEpoch) {
// If the received leader epoch is at least the same as the previous one, update the metadata
log.debug("Updating last seen epoch for partition {} from {} to epoch {} from new metadata", tp, currentEpoch, newEpoch);
lastSeenLeaderEpochs.put(tp, newEpoch);
return Optional.of(partitionMetadata);
} else {
// Otherwise ignore the new metadata and use the previously cached info
log.debug("Got metadata for an older epoch {} (current is {}) for partition {}, not updating", newEpoch, currentEpoch, tp);
return cache.partitionMetadata(tp);
}
} else {
// Handle old cluster formats as well as error responses where leader and epoch are missing
lastSeenLeaderEpochs.remove(tp);
return Optional.of(partitionMetadata.withoutLeaderEpoch());
}
}
/**
* If any non-retriable exceptions were encountered during metadata update, clear and throw the exception.
* This is used by the consumer to propagate any fatal exceptions or topic exceptions for any of the topics
* in the consumer's Metadata.
*/
public synchronized void maybeThrowAnyException() {
clearErrorsAndMaybeThrowException(this::recoverableException);
}
/**
* If any fatal exceptions were encountered during metadata update, throw the exception. This is used by
* the producer to abort waiting for metadata if there were fatal exceptions (e.g. authentication failures)
* in the last metadata update.
*/
protected synchronized void maybeThrowFatalException() {
KafkaException metadataException = this.fatalException;
if (metadataException != null) {
fatalException = null;
throw metadataException;
}
}
/**
* If any non-retriable exceptions were encountered during metadata update, throw exception if the exception
* is fatal or related to the specified topic. All exceptions from the last metadata update are cleared.
* This is used by the producer to propagate topic metadata errors for send requests.
*/
public synchronized void maybeThrowExceptionForTopic(String topic) {
clearErrorsAndMaybeThrowException(() -> recoverableExceptionForTopic(topic));
}
private void clearErrorsAndMaybeThrowException(Supplier<KafkaException> recoverableExceptionSupplier) {
KafkaException metadataException = Optional.ofNullable(fatalException).orElseGet(recoverableExceptionSupplier);
fatalException = null;
clearRecoverableErrors();
if (metadataException != null)
throw metadataException;
}
// We may be able to recover from this exception if metadata for this topic is no longer needed
private KafkaException recoverableException() {
if (!unauthorizedTopics.isEmpty())
return new TopicAuthorizationException(unauthorizedTopics);
else if (!invalidTopics.isEmpty())
return new InvalidTopicException(invalidTopics);
else
return null;
}
private KafkaException recoverableExceptionForTopic(String topic) {
if (unauthorizedTopics.contains(topic))
return new TopicAuthorizationException(Collections.singleton(topic));
else if (invalidTopics.contains(topic))
return new InvalidTopicException(Collections.singleton(topic));
else
return null;
}
private void clearRecoverableErrors() {
invalidTopics = Collections.emptySet();
unauthorizedTopics = Collections.emptySet();
}
/**
* Record an attempt to update the metadata that failed. We need to keep track of this
* to avoid retrying immediately.
*/
public synchronized void failedUpdate(long now) {
this.lastRefreshMs = now;
}
/**
* Propagate a fatal error which affects the ability to fetch metadata for the cluster.
* Two examples are authentication and unsupported version exceptions.
*
* @param exception The fatal exception
*/
public synchronized void fatalError(KafkaException exception) {
this.fatalException = exception;
}
/**
* @return The current metadata updateVersion
*/
public synchronized int updateVersion() {
return this.updateVersion;
}
/**
* The last time metadata was successfully updated.
*/
public synchronized long lastSuccessfulUpdate() {
return this.lastSuccessfulRefreshMs;
}
/**
* Close this metadata instance to indicate that metadata updates are no longer possible.
*/
@Override
public synchronized void close() {
this.isClosed = true;
}
/**
* Check if this metadata instance has been closed. See {@link #close()} for more information.
*
* @return True if this instance has been closed; false otherwise
*/
public synchronized boolean isClosed() {
return this.isClosed;
}
public synchronized MetadataRequestAndVersion newMetadataRequestAndVersion(long nowMs) {
MetadataRequest.Builder request = null;
boolean isPartialUpdate = false;
// Perform a partial update only if a full update hasn't been requested, and the last successful
// hasn't exceeded the metadata refresh time.
if (!this.needFullUpdate && this.lastSuccessfulRefreshMs + this.metadataExpireMs > nowMs) {
request = newMetadataRequestBuilderForNewTopics();
isPartialUpdate = true;
}
if (request == null) {
request = newMetadataRequestBuilder();
isPartialUpdate = false;
}
return new MetadataRequestAndVersion(request, requestVersion, isPartialUpdate);
}
/**
* Constructs and returns a metadata request builder for fetching cluster data and all active topics.
*
* @return the constructed non-null metadata builder
*/
protected MetadataRequest.Builder newMetadataRequestBuilder() {
return MetadataRequest.Builder.allTopics();
}
/**
* Constructs and returns a metadata request builder for fetching cluster data and any uncached topics,
* otherwise null if the functionality is not supported.
*
* @return the constructed metadata builder, or null if not supported
*/
protected MetadataRequest.Builder newMetadataRequestBuilderForNewTopics() {
return null;
}
protected boolean retainTopic(String topic, boolean isInternal, long nowMs) {
return true;
}
public static class MetadataRequestAndVersion {
public final MetadataRequest.Builder requestBuilder;
public final int requestVersion;
public final boolean isPartialUpdate;
private MetadataRequestAndVersion(MetadataRequest.Builder requestBuilder,
int requestVersion,
boolean isPartialUpdate) {
this.requestBuilder = requestBuilder;
this.requestVersion = requestVersion;
this.isPartialUpdate = isPartialUpdate;
}
}
/**
* Represents current leader state known in metadata. It is possible that we know the leader, but not the
* epoch if the metadata is received from a broker which does not support a sufficient Metadata API version.
* It is also possible that we know of the leader epoch, but not the leader when it is derived
* from an external source (e.g. a committed offset).
*/
public static class LeaderAndEpoch {
private static final LeaderAndEpoch NO_LEADER_OR_EPOCH = new LeaderAndEpoch(Optional.empty(), Optional.empty());
public final Optional<Node> leader;
public final Optional<Integer> epoch;
public LeaderAndEpoch(Optional<Node> leader, Optional<Integer> epoch) {
this.leader = Objects.requireNonNull(leader);
this.epoch = Objects.requireNonNull(epoch);
}
public static LeaderAndEpoch noLeaderOrEpoch() {
return NO_LEADER_OR_EPOCH;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
LeaderAndEpoch that = (LeaderAndEpoch) o;
if (!leader.equals(that.leader)) return false;
return epoch.equals(that.epoch);
}
@Override
public int hashCode() {
int result = leader.hashCode();
result = 31 * result + epoch.hashCode();
return result;
}
@Override
public String toString() {
return "LeaderAndEpoch{" +
"leader=" + leader +
", epoch=" + epoch.map(Number::toString).orElse("absent") +
'}';
}
}
}
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