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* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* 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.
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package org.elasticsearch.cluster.routing.allocation.command;
import org.elasticsearch.ElasticsearchParseException;
import org.elasticsearch.cluster.node.DiscoveryNode;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.cluster.routing.RoutingNode;
import org.elasticsearch.cluster.routing.ShardRoutingState;
import org.elasticsearch.cluster.routing.allocation.RerouteExplanation;
import org.elasticsearch.cluster.routing.allocation.RoutingAllocation;
import org.elasticsearch.cluster.routing.allocation.decider.Decision;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.xcontent.ToXContent;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.index.shard.ShardId;
import java.io.IOException;
/**
* A command that moves a shard from a specific node to another node.<br>
* <b>Note:</b> The shard needs to be in the state
* {@link ShardRoutingState#STARTED} in order to be moved.
*/
public class MoveAllocationCommand implements AllocationCommand {
public static final String NAME = "move";
public static class Factory implements AllocationCommand.Factory<MoveAllocationCommand> {
@Override
public MoveAllocationCommand readFrom(StreamInput in) throws IOException {
return new MoveAllocationCommand(ShardId.readShardId(in), in.readString(), in.readString());
}
@Override
public void writeTo(MoveAllocationCommand command, StreamOutput out) throws IOException {
command.shardId().writeTo(out);
out.writeString(command.fromNode());
out.writeString(command.toNode());
}
@Override
public MoveAllocationCommand fromXContent(XContentParser parser) throws IOException {
String index = null;
int shardId = -1;
String fromNode = null;
String toNode = null;
String currentFieldName = null;
XContentParser.Token token;
while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
currentFieldName = parser.currentName();
} else if (token.isValue()) {
if ("index".equals(currentFieldName)) {
index = parser.text();
} else if ("shard".equals(currentFieldName)) {
shardId = parser.intValue();
} else if ("from_node".equals(currentFieldName) || "fromNode".equals(currentFieldName)) {
fromNode = parser.text();
} else if ("to_node".equals(currentFieldName) || "toNode".equals(currentFieldName)) {
toNode = parser.text();
} else {
throw new ElasticsearchParseException("[{}] command does not support field [{}]", NAME, currentFieldName);
}
} else {
throw new ElasticsearchParseException("[{}] command does not support complex json tokens [{}]", NAME, token);
}
}
if (index == null) {
throw new ElasticsearchParseException("[{}] command missing the index parameter", NAME);
}
if (shardId == -1) {
throw new ElasticsearchParseException("[{}] command missing the shard parameter", NAME);
}
if (fromNode == null) {
throw new ElasticsearchParseException("[{}] command missing the from_node parameter", NAME);
}
if (toNode == null) {
throw new ElasticsearchParseException("[{}] command missing the to_node parameter", NAME);
}
return new MoveAllocationCommand(new ShardId(index, shardId), fromNode, toNode);
}
@Override
public void toXContent(MoveAllocationCommand command, XContentBuilder builder, ToXContent.Params params, String objectName) throws IOException {
if (objectName == null) {
builder.startObject();
} else {
builder.startObject(objectName);
}
builder.field("index", command.shardId().index().name());
builder.field("shard", command.shardId().id());
builder.field("from_node", command.fromNode());
builder.field("to_node", command.toNode());
builder.endObject();
}
}
private final ShardId shardId;
private final String fromNode;
private final String toNode;
public MoveAllocationCommand(ShardId shardId, String fromNode, String toNode) {
this.shardId = shardId;
this.fromNode = fromNode;
this.toNode = toNode;
}
@Override
public String name() {
return NAME;
}
public ShardId shardId() {
return this.shardId;
}
public String fromNode() {
return this.fromNode;
}
public String toNode() {
return this.toNode;
}
@Override
public RerouteExplanation execute(RoutingAllocation allocation, boolean explain) {
DiscoveryNode fromDiscoNode = allocation.nodes().resolveNode(fromNode);
DiscoveryNode toDiscoNode = allocation.nodes().resolveNode(toNode);
Decision decision = null;
boolean found = false;
for (ShardRouting shardRouting : allocation.routingNodes().node(fromDiscoNode.id())) {
if (!shardRouting.shardId().equals(shardId)) {
continue;
}
found = true;
// TODO we can possibly support also relocating cases, where we cancel relocation and move...
if (!shardRouting.started()) {
if (explain) {
return new RerouteExplanation(this, allocation.decision(Decision.NO, "move_allocation_command",
"shard " + shardId + " has not been started"));
}
throw new IllegalArgumentException("[move_allocation] can't move " + shardId +
", shard is not started (state = " + shardRouting.state() + "]");
}
RoutingNode toRoutingNode = allocation.routingNodes().node(toDiscoNode.id());
decision = allocation.deciders().canAllocate(shardRouting, toRoutingNode, allocation);
if (decision.type() == Decision.Type.NO) {
if (explain) {
return new RerouteExplanation(this, decision);
}
throw new IllegalArgumentException("[move_allocation] can't move " + shardId + ", from " + fromDiscoNode + ", to " + toDiscoNode + ", since its not allowed, reason: " + decision);
}
if (decision.type() == Decision.Type.THROTTLE) {
// its being throttled, maybe have a flag to take it into account and fail? for now, just do it since the "user" wants it...
}
allocation.routingNodes().relocate(shardRouting, toRoutingNode.nodeId(), allocation.clusterInfo().getShardSize(shardRouting, ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE));
}
if (!found) {
if (explain) {
return new RerouteExplanation(this, allocation.decision(Decision.NO,
"move_allocation_command", "shard " + shardId + " not found"));
}
throw new IllegalArgumentException("[move_allocation] can't move " + shardId + ", failed to find it on node " + fromDiscoNode);
}
return new RerouteExplanation(this, decision);
}
}