Many resources are needed to download a project. Please understand that we have to compensate our server costs. Thank you in advance. Project price only 1 $
You can buy this project and download/modify it how often you want.
/*
* 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.connect.runtime.distributed;
import org.apache.kafka.common.utils.CircularIterator;
import org.apache.kafka.common.utils.LogContext;
import org.apache.kafka.connect.util.ConnectorTaskId;
import org.slf4j.Logger;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import static org.apache.kafka.common.message.JoinGroupResponseData.JoinGroupResponseMember;
import static org.apache.kafka.connect.runtime.distributed.ConnectProtocol.Assignment;
import static org.apache.kafka.connect.runtime.distributed.WorkerCoordinator.LeaderState;
/**
* An assignor that computes a unweighted round-robin distribution of connectors and tasks. The
* connectors are assigned to the workers first, followed by the tasks. This is to avoid
* load imbalance when several 1-task connectors are running, given that a connector is usually
* more lightweight than a task.
*
* Note that this class is NOT thread-safe.
*/
public class EagerAssignor implements ConnectAssignor {
private final Logger log;
public EagerAssignor(LogContext logContext) {
this.log = logContext.logger(EagerAssignor.class);
}
@Override
public Map performAssignment(String leaderId, String protocol,
List allMemberMetadata,
WorkerCoordinator coordinator) {
log.debug("Performing task assignment");
Map memberConfigs = new HashMap<>();
for (JoinGroupResponseMember member : allMemberMetadata)
memberConfigs.put(member.memberId(), IncrementalCooperativeConnectProtocol.deserializeMetadata(ByteBuffer.wrap(member.metadata())));
long maxOffset = findMaxMemberConfigOffset(memberConfigs, coordinator);
Long leaderOffset = ensureLeaderConfig(maxOffset, coordinator);
if (leaderOffset == null)
return fillAssignmentsAndSerialize(memberConfigs.keySet(), Assignment.CONFIG_MISMATCH,
leaderId, memberConfigs.get(leaderId).url(), maxOffset,
new HashMap<>(), new HashMap<>());
return performTaskAssignment(leaderId, leaderOffset, memberConfigs, coordinator);
}
private Long ensureLeaderConfig(long maxOffset, WorkerCoordinator coordinator) {
// If this leader is behind some other members, we can't do assignment
if (coordinator.configSnapshot().offset() < maxOffset) {
// We might be able to take a new snapshot to catch up immediately and avoid another round of syncing here.
// Alternatively, if this node has already passed the maximum reported by any other member of the group, it
// is also safe to use this newer state.
ClusterConfigState updatedSnapshot = coordinator.configFreshSnapshot();
if (updatedSnapshot.offset() < maxOffset) {
log.info("Was selected to perform assignments, but do not have latest config found in sync request. " +
"Returning an empty configuration to trigger re-sync.");
return null;
} else {
coordinator.configSnapshot(updatedSnapshot);
return updatedSnapshot.offset();
}
}
return maxOffset;
}
private Map performTaskAssignment(String leaderId, long maxOffset,
Map memberConfigs,
WorkerCoordinator coordinator) {
Map> connectorAssignments = new HashMap<>();
Map> taskAssignments = new HashMap<>();
// Perform round-robin task assignment. Assign all connectors and then all tasks because assigning both the
// connector and its tasks can lead to very uneven distribution of work in some common cases (e.g. for connectors
// that generate only 1 task each; in a cluster of 2 or an even # of nodes, only even nodes will be assigned
// connectors and only odd nodes will be assigned tasks, but tasks are, on average, actually more resource
// intensive than connectors).
List connectorsSorted = sorted(coordinator.configSnapshot().connectors());
CircularIterator memberIt = new CircularIterator<>(sorted(memberConfigs.keySet()));
for (String connectorId : connectorsSorted) {
String connectorAssignedTo = memberIt.next();
log.trace("Assigning connector {} to {}", connectorId, connectorAssignedTo);
Collection memberConnectors = connectorAssignments.get(connectorAssignedTo);
if (memberConnectors == null) {
memberConnectors = new ArrayList<>();
connectorAssignments.put(connectorAssignedTo, memberConnectors);
}
memberConnectors.add(connectorId);
}
for (String connectorId : connectorsSorted) {
for (ConnectorTaskId taskId : sorted(coordinator.configSnapshot().tasks(connectorId))) {
String taskAssignedTo = memberIt.next();
log.trace("Assigning task {} to {}", taskId, taskAssignedTo);
Collection memberTasks = taskAssignments.get(taskAssignedTo);
if (memberTasks == null) {
memberTasks = new ArrayList<>();
taskAssignments.put(taskAssignedTo, memberTasks);
}
memberTasks.add(taskId);
}
}
coordinator.leaderState(new LeaderState(memberConfigs, connectorAssignments, taskAssignments));
return fillAssignmentsAndSerialize(memberConfigs.keySet(), Assignment.NO_ERROR,
leaderId, memberConfigs.get(leaderId).url(), maxOffset, connectorAssignments, taskAssignments);
}
private Map fillAssignmentsAndSerialize(Collection members,
short error,
String leaderId,
String leaderUrl,
long maxOffset,
Map> connectorAssignments,
Map> taskAssignments) {
Map groupAssignment = new HashMap<>();
for (String member : members) {
Collection connectors = connectorAssignments.get(member);
if (connectors == null) {
connectors = Collections.emptyList();
}
Collection tasks = taskAssignments.get(member);
if (tasks == null) {
tasks = Collections.emptyList();
}
Assignment assignment = new Assignment(error, leaderId, leaderUrl, maxOffset, connectors, tasks);
log.debug("Assignment: {} -> {}", member, assignment);
groupAssignment.put(member, ConnectProtocol.serializeAssignment(assignment));
}
log.debug("Finished assignment");
return groupAssignment;
}
private long findMaxMemberConfigOffset(Map memberConfigs,
WorkerCoordinator coordinator) {
// The new config offset is the maximum seen by any member. We always perform assignment using this offset,
// even if some members have fallen behind. The config offset used to generate the assignment is included in
// the response so members that have fallen behind will not use the assignment until they have caught up.
Long maxOffset = null;
for (Map.Entry stateEntry : memberConfigs.entrySet()) {
long memberRootOffset = stateEntry.getValue().offset();
if (maxOffset == null)
maxOffset = memberRootOffset;
else
maxOffset = Math.max(maxOffset, memberRootOffset);
}
log.debug("Max config offset root: {}, local snapshot config offsets root: {}",
maxOffset, coordinator.configSnapshot().offset());
return maxOffset;
}
private static > List sorted(Collection members) {
List res = new ArrayList<>(members);
Collections.sort(res);
return res;
}
}
