You are viewing a plain text version of this content. The canonical link for it is here.
Posted to jira@kafka.apache.org by GitBox <gi...@apache.org> on 2022/11/01 14:45:13 UTC
[GitHub] [kafka] mumrah commented on a diff in pull request #12776: KAFKA-14327: Unify KRaft snapshot generation between broker and controller
mumrah commented on code in PR #12776:
URL: https://github.com/apache/kafka/pull/12776#discussion_r1010479679
##########
metadata/src/main/java/org/apache/kafka/image/publisher/SnapshotGenerator.java:
##########
@@ -0,0 +1,262 @@
+/*
+ * 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 org.apache.kafka.image.publisher;
+
+import org.apache.kafka.common.utils.LogContext;
+import org.apache.kafka.common.utils.Time;
+import org.apache.kafka.image.MetadataDelta;
+import org.apache.kafka.image.MetadataImage;
+import org.apache.kafka.image.loader.LogDeltaManifest;
+import org.apache.kafka.image.loader.PreVersionChangeManifest;
+import org.apache.kafka.image.loader.SnapshotManifest;
+import org.apache.kafka.queue.EventQueue;
+import org.apache.kafka.queue.KafkaEventQueue;
+import org.apache.kafka.server.fault.FaultHandler;
+import org.slf4j.Logger;
+
+import java.util.concurrent.TimeUnit;
+
+
+/**
+ * A metadata publisher that generates snapshots when appropriate.
+ */
+public class SnapshotGenerator implements MetadataPublisher {
+ public static class Builder {
+ private int nodeId = 0;
+ private Time time = Time.SYSTEM;
+ private Emitter emitter = null;
+ private FaultHandler faultHandler = (m, e) -> null;
+ private long minBytesSinceLastSnapshot = 100 * 1024L * 1024L;
+ private long minTimeSinceLastSnapshotNs = TimeUnit.DAYS.toNanos(1);
+
+ public Builder setNodeId(int nodeId) {
+ this.nodeId = nodeId;
+ return this;
+ }
+
+ public Builder setTime(Time time) {
+ this.time = time;
+ return this;
+ }
+
+ public Builder setEmitter(Emitter emitter) {
+ this.emitter = emitter;
+ return this;
+ }
+
+ public Builder setFaultHandler(FaultHandler faultHandler) {
+ this.faultHandler = faultHandler;
+ return this;
+ }
+
+ public Builder setMinBytesSinceLastSnapshot(long minBytesSinceLastSnapshot) {
+ this.minBytesSinceLastSnapshot = minBytesSinceLastSnapshot;
+ return this;
+ }
+
+ public Builder setMinTimeSinceLastSnapshotNs(long minTimeSinceLastSnapshotNs) {
+ this.minTimeSinceLastSnapshotNs = minTimeSinceLastSnapshotNs;
+ return this;
+ }
+
+ public SnapshotGenerator build() {
+ if (emitter == null) throw new RuntimeException("You must set a snapshot emitter.");
+ return new SnapshotGenerator(
+ nodeId,
+ time,
+ emitter,
+ faultHandler,
+ minBytesSinceLastSnapshot,
+ minTimeSinceLastSnapshotNs
+ );
+ }
+ }
+
+ /**
+ * The callback which actually generates the snapshot.
+ */
+ public interface Emitter {
+ void emit(MetadataImage image);
+ }
+
+ /**
+ * The node ID.
+ */
+ private final int nodeId;
+
+ /**
+ * The clock to use.
+ */
+ private final Time time;
+
+ /**
+ * The emitter callback, which actually generates the snapshot.
+ */
+ private final Emitter emitter;
+
+ /**
+ * The slf4j logger to use.
+ */
+ private final Logger log;
+
+ /**
+ * The fault handler to use.
+ */
+ private final FaultHandler faultHandler;
+
+ /**
+ * The minimum number of bytes we will wait to see before emitting a snapshot.
+ */
+ private final long minBytesSinceLastSnapshot;
+
+ /**
+ * The minimum amount of time we will wait before emitting a snapshot, or 0 to disable
+ * time-based snapshotting.
+ */
+ private final long minTimeSinceLastSnapshotNs;
+
+ /**
+ * If non-null, the reason why snapshots have been disabled.
+ */
+ private volatile String disabledReason;
+
+ /**
+ * The event queue used to schedule emitting snapshots.
+ */
+ private final EventQueue eventQueue;
+
+ /**
+ * The log bytes that we have read since the last snapshot.
+ */
+ private long bytesSinceLastSnapshot;
+
+ /**
+ * The time at which we created the last snapshot.
+ */
+ private long lastSnapshotTimeNs;
+
+ private SnapshotGenerator(
+ int nodeId,
+ Time time,
+ Emitter emitter,
+ FaultHandler faultHandler,
+ long minBytesSinceLastSnapshot,
+ long minTimeSinceLastSnapshotNs
+ ) {
+ this.nodeId = nodeId;
+ this.time = time;
+ this.emitter = emitter;
+ this.faultHandler = faultHandler;
+ this.minBytesSinceLastSnapshot = minBytesSinceLastSnapshot;
+ this.minTimeSinceLastSnapshotNs = minTimeSinceLastSnapshotNs;
+ LogContext logContext = new LogContext("[SnapshotGenerator " + nodeId + "] ");
+ this.log = logContext.logger(SnapshotGenerator.class);
+ this.disabledReason = null;
+ this.eventQueue = new KafkaEventQueue(time, logContext, "");
+ resetSnapshotCounters();
+ }
+
+ @Override
+ public String name() {
+ return "SnapshotGenerator";
+ }
+
+ void resetSnapshotCounters() {
+ this.bytesSinceLastSnapshot = 0L;
+ this.lastSnapshotTimeNs = time.nanoseconds();
+ }
+
+ @Override
+ public void publishSnapshot(
+ MetadataDelta delta,
+ MetadataImage newImage,
+ SnapshotManifest manifest
+ ) {
+ // Reset the snapshot counters because we just read a snapshot.
+ resetSnapshotCounters();
+ }
+
+ @Override
+ public void publishPreVersionChangeImage(
+ MetadataDelta delta,
+ MetadataImage preVersionChangeImage,
+ PreVersionChangeManifest manifest
+ ) {
+ scheduleEmit("the metadata version changed", preVersionChangeImage);
+ }
+
+ @Override
+ public void publishLogDelta(
+ MetadataDelta delta,
+ MetadataImage newImage,
+ LogDeltaManifest manifest
+ ) {
+ bytesSinceLastSnapshot += manifest.numBytes();
+ if (bytesSinceLastSnapshot >= minBytesSinceLastSnapshot) {
+ if (eventQueue.isEmpty()) {
+ scheduleEmit("we have replayed at least " + minBytesSinceLastSnapshot +
+ " bytes", newImage);
+ }
+ } else if (minTimeSinceLastSnapshotNs != 0 &&
+ (time.nanoseconds() - lastSnapshotTimeNs >= minTimeSinceLastSnapshotNs)) {
+ if (eventQueue.isEmpty()) {
+ scheduleEmit("we have waited at least " +
+ TimeUnit.NANOSECONDS.toMinutes(minTimeSinceLastSnapshotNs) + " minute(s)", newImage);
+ }
+ }
+ }
+
+ void scheduleEmit(
+ String reason,
+ MetadataImage image
+ ) {
+ resetSnapshotCounters();
+ eventQueue.append(() -> {
+ String currentDisabledReason = disabledReason;
+ if (currentDisabledReason != null) {
+ log.error("Not emitting {} despite the fact that {} because snapshots are " +
+ "disabled; {}", image.provenance().snapshotName(), reason,
+ currentDisabledReason);
+ } else {
+ log.info("Creating new KRaft snapshot file {} because {}.",
+ image.provenance().snapshotName(), reason);
+ try {
+ emitter.emit(image);
+ } catch (Throwable e) {
+ faultHandler.handleFault("KRaft snapshot file generation error", e);
+ }
+ }
+ });
+ }
+
+ public void beginShutdown() {
+ this.disabledReason = "we are shutting down";
+ eventQueue.beginShutdown("beginShutdown");
+ }
+
+ public void disable(String disabledReason) {
+ log.error("Disabling periodic KRaft snapshot generation because {}.", disabledReason);
+ this.disabledReason = disabledReason;
Review Comment:
I think if we pass `null` here, it will re-enable snapshot generation. Do we want to allow that? Or should snapshot disabling be irreversible until restart?
##########
core/src/main/scala/kafka/server/KafkaRaftServer.scala:
##########
@@ -81,26 +83,69 @@ class KafkaRaftServer(
controllerQuorumVotersFuture
)
+ private val snapshotEmitter: SnapshotEmitter = new SnapshotEmitter.Builder().
+ setNodeId(config.nodeId).
+ setRaftClient(raftManager.client).
+ build()
+
+ private val snapshotGenerator: SnapshotGenerator = new SnapshotGenerator.Builder().
+ setTime(Time.SYSTEM).
+ setNodeId(config.nodeId).
+ setFaultHandler(new LoggingFaultHandler("snapshot generation", () => { })).
+ setEmitter(snapshotEmitter).
+ setMinBytesSinceLastSnapshot(config.metadataSnapshotMaxNewRecordBytes).
+ setMinTimeSinceLastSnapshotNs(TimeUnit.MILLISECONDS.toNanos(config.metadataSnapshotMaxIntervalMsProp)).
+ build()
+
+ private val brokerMetrics: Option[BrokerServerMetrics] = if (config.processRoles.contains(BrokerRole)) {
+ Some(BrokerServerMetrics(metrics))
+ } else {
+ None
+ }
+
+ private val metadataLoader: MetadataLoader = {
+ val builder = new MetadataLoader.Builder().
+ setTime(Time.SYSTEM).
Review Comment:
Same comment as above ^
##########
core/src/main/scala/kafka/server/KafkaRaftServer.scala:
##########
@@ -81,26 +83,69 @@ class KafkaRaftServer(
controllerQuorumVotersFuture
)
+ private val snapshotEmitter: SnapshotEmitter = new SnapshotEmitter.Builder().
+ setNodeId(config.nodeId).
+ setRaftClient(raftManager.client).
+ build()
+
+ private val snapshotGenerator: SnapshotGenerator = new SnapshotGenerator.Builder().
+ setTime(Time.SYSTEM).
Review Comment:
Should be the `time: Time` passed into KafkaRaftServer
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: jira-unsubscribe@kafka.apache.org
For queries about this service, please contact Infrastructure at:
users@infra.apache.org