org.elasticsearch.cluster.routing.allocation.AllocationExplanation Maven / Gradle / Ivy
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* ownership. Elasticsearch 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.elasticsearch.cluster.routing.allocation;
import com.google.common.collect.Maps;
import org.elasticsearch.cluster.node.DiscoveryNode;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.io.stream.Streamable;
import org.elasticsearch.index.shard.ShardId;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
/**
* Instances of this class keeps explanations of decisions that have been made by allocation.
* An {@link AllocationExplanation} consists of a set of per node explanations.
* Since {@link NodeExplanation}s are related to shards an {@link AllocationExplanation} maps
* a shards id to a set of {@link NodeExplanation}s.
*/
public class AllocationExplanation implements Streamable {
public static final AllocationExplanation EMPTY = new AllocationExplanation();
/**
* Instances of this class keep messages and informations about nodes of an allocation
*/
public static class NodeExplanation {
private final DiscoveryNode node;
private final String description;
/**
* Creates a new {@link NodeExplanation}
*
* @param node node referenced by this {@link NodeExplanation}
* @param description a message associated with the given node
*/
public NodeExplanation(DiscoveryNode node, String description) {
this.node = node;
this.description = description;
}
/**
* The node referenced by the explanation
* @return referenced node
*/
public DiscoveryNode node() {
return node;
}
/**
* Get the explanation for the node
* @return explanation for the node
*/
public String description() {
return description;
}
}
private final Map> explanations = Maps.newHashMap();
/**
* Create and add a node explanation to this explanation referencing a shard
* @param shardId id the of the referenced shard
* @param nodeExplanation Explanation itself
* @return AllocationExplanation involving the explanation
*/
public AllocationExplanation add(ShardId shardId, NodeExplanation nodeExplanation) {
List list = explanations.get(shardId);
if (list == null) {
list = new ArrayList<>();
explanations.put(shardId, list);
}
list.add(nodeExplanation);
return this;
}
/**
* List of explanations involved by this AllocationExplanation
* @return Map of shard ids and corresponding explanations
*/
public Map> explanations() {
return this.explanations;
}
/**
* Read an {@link AllocationExplanation} from an {@link StreamInput}
* @param in {@link StreamInput} to read from
* @return a new {@link AllocationExplanation} read from the stream
* @throws IOException if something bad happened while reading
*/
public static AllocationExplanation readAllocationExplanation(StreamInput in) throws IOException {
AllocationExplanation e = new AllocationExplanation();
e.readFrom(in);
return e;
}
@Override
public void readFrom(StreamInput in) throws IOException {
int size = in.readVInt();
for (int i = 0; i < size; i++) {
ShardId shardId = ShardId.readShardId(in);
int size2 = in.readVInt();
List ne = new ArrayList<>(size2);
for (int j = 0; j < size2; j++) {
DiscoveryNode node = null;
if (in.readBoolean()) {
node = DiscoveryNode.readNode(in);
}
ne.add(new NodeExplanation(node, in.readString()));
}
explanations.put(shardId, ne);
}
}
@Override
public void writeTo(StreamOutput out) throws IOException {
out.writeVInt(explanations.size());
for (Map.Entry> entry : explanations.entrySet()) {
entry.getKey().writeTo(out);
out.writeVInt(entry.getValue().size());
for (NodeExplanation nodeExplanation : entry.getValue()) {
if (nodeExplanation.node() == null) {
out.writeBoolean(false);
} else {
out.writeBoolean(true);
nodeExplanation.node().writeTo(out);
}
out.writeString(nodeExplanation.description());
}
}
}
}