io.atomix.raft.storage.log.entry.ConfigurationEntry Maven / Gradle / Ivy
/*
* Copyright 2015-present Open Networking Foundation
* Copyright © 2020 camunda services GmbH ([email protected])
*
* Licensed 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 io.atomix.raft.storage.log.entry;
import static io.netty.util.internal.ObjectUtil.checkNotNull;
import io.atomix.raft.cluster.RaftMember;
import io.atomix.raft.storage.serializer.RaftEntrySerializer;
import io.atomix.raft.storage.serializer.RaftEntrySerializer.SerializedBufferWriterAdapter;
import io.camunda.zeebe.util.buffer.BufferWriter;
import java.util.Collection;
import java.util.Collections;
/**
* Stores a cluster configuration.
*
* The {@code ConfigurationEntry} stores information relevant to a single cluster configuration
* change. Configuration change entries store a collection of {@link RaftMember newMembers} which
* each represent a server in the cluster. Each time the set of members changes or a property of a
* single member changes, a new {@code ConfigurationEntry} must be logged for the configuration
* change. If the set of members changes, the {@code ConfigurationEntry} must be committed by a
* quorum of the old members and a quorum of the new members.
*/
public record ConfigurationEntry(
long timestamp, Collection newMembers, Collection oldMembers)
implements RaftEntry {
public ConfigurationEntry {
checkNotNull(newMembers, "newMembers cannot be null");
checkNotNull(oldMembers, "oldMembers cannot be null");
}
public ConfigurationEntry(final long timestamp, final Collection newMembers) {
this(timestamp, newMembers, Collections.emptyList());
}
/**
* @return true if the configuration change requires joint consensus, i.e. when the set of members
* has changed.
*/
public boolean requiresJointConsensus() {
return !oldMembers.isEmpty();
}
@Override
public BufferWriter toSerializable(final long term, final RaftEntrySerializer serializer) {
return new SerializedBufferWriterAdapter(
() -> serializer.getConfigurationEntrySerializedLength(this),
(buffer, offset) -> serializer.writeConfigurationEntry(term, this, buffer, offset));
}
}