Add core coordination algorithm for cluster state publishing

server/src/main/java/org/elasticsearch/ElasticsearchException.java

@@ -21,6 +21,7 @@
 
 import org.elasticsearch.action.support.replication.ReplicationOperation;
 import org.elasticsearch.cluster.action.shard.ShardStateAction;
+import org.elasticsearch.cluster.coordination.CoordinationStateRejectedException;
 import org.elasticsearch.common.CheckedFunction;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.ParseField;
@@ -1024,8 +1025,10 @@ private enum ElasticsearchExceptionHandle {
         UNKNOWN_NAMED_OBJECT_EXCEPTION(org.elasticsearch.common.xcontent.UnknownNamedObjectException.class,
                 org.elasticsearch.common.xcontent.UnknownNamedObjectException::new, 148, Version.V_5_2_0),
         TOO_MANY_BUCKETS_EXCEPTION(MultiBucketConsumerService.TooManyBucketsException.class,
-                                   MultiBucketConsumerService.TooManyBucketsException::new, 149,
-            Version.V_7_0_0_alpha1);
+            MultiBucketConsumerService.TooManyBucketsException::new, 149, Version.V_7_0_0_alpha1),
+        COORDINATION_STATE_REJECTED_EXCEPTION(CoordinationStateRejectedException.class,
+            CoordinationStateRejectedException::new, 150, Version.V_7_0_0_alpha1);
+
 
         final Class<? extends ElasticsearchException> exceptionClass;
         final CheckedFunction<StreamInput, ? extends ElasticsearchException, IOException> constructor;

server/src/main/java/org/elasticsearch/cluster/coordination/ApplyCommitRequest.java

@@ -0,0 +1,54 @@
+/*
+ * 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.
+ */
+package org.elasticsearch.cluster.coordination;
+
+import org.elasticsearch.cluster.node.DiscoveryNode;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * A master node sends this request to its peers to inform them that it could commit the
+ * cluster state with the given term and version. Peers that have accepted the given cluster
+ * state will then consider it as committed and proceed to apply the state locally.
+ */
+public class ApplyCommitRequest extends TermVersionRequest {
+
+    public ApplyCommitRequest(DiscoveryNode sourceNode, long term, long version) {
+        super(sourceNode, term, version);
+    }
+
+    public ApplyCommitRequest(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+    }
+
+    @Override
+    public String toString() {
+        return "ApplyCommitRequest{" +
+            "term=" + term +
+            ", version=" + version +
+            '}';
+    }
+}

server/src/main/java/org/elasticsearch/cluster/coordination/CoordinationStateRejectedException.java

@@ -0,0 +1,42 @@
+/*
+ * 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.
+ */
+
+package org.elasticsearch.cluster.coordination;
+
+import org.elasticsearch.ElasticsearchException;
+import org.elasticsearch.common.io.stream.StreamInput;
+
+import java.io.IOException;
+
+/**
+ * This exception is thrown when rejecting state transitions on the {@link CoordinationState} object,
+ * for example when receiving a publish request with the wrong term or version.
+ * Occurrences of this exception don't always signal failures, but can often be just caused by the
+ * asynchronous, distributed nature of the system. They will, for example, naturally happen during
+ * leader election, if multiple nodes are trying to become leader at the same time.
+ */
+public class CoordinationStateRejectedException extends ElasticsearchException {
+    public CoordinationStateRejectedException(String msg, Object... args) {
+        super(msg, args);
+    }
+
+    public CoordinationStateRejectedException(StreamInput in) throws IOException {
+        super(in);
+    }
+}

server/src/main/java/org/elasticsearch/cluster/coordination/Join.java

@@ -0,0 +1,127 @@
+/*
+ * 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.
+ */
+package org.elasticsearch.cluster.coordination;
+
+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.Writeable;
+
+import java.io.IOException;
+
+/**
+ * Triggered by a {@link StartJoinRequest}, instances of this class represent join votes,
+ * and have a source and target node. The source node is the node that provides the vote,
+ * and the target node is the node for which this vote is casted. A node will only cast
+ * a single vote per term, and this for a unique target node. The vote also carries
+ * information about the current state of the node that provided the vote, so that
+ * the receiver of the vote can determine if it has a more up-to-date state than the
+ * source node.
+ */
+public class Join implements Writeable {
+    private final DiscoveryNode sourceNode;
+    private final DiscoveryNode targetNode;
+    private final long term;
+    private final long lastAcceptedTerm;
+    private final long lastAcceptedVersion;
+
+    public Join(DiscoveryNode sourceNode, DiscoveryNode targetNode, long term, long lastAcceptedTerm, long lastAcceptedVersion) {
+        assert term >= 0;
+        assert lastAcceptedTerm >= 0;
+        assert lastAcceptedVersion >= 0;
+
+        this.sourceNode = sourceNode;
+        this.targetNode = targetNode;
+        this.term = term;
+        this.lastAcceptedTerm = lastAcceptedTerm;
+        this.lastAcceptedVersion = lastAcceptedVersion;
+    }
+
+    public Join(StreamInput in) throws IOException {
+        sourceNode = new DiscoveryNode(in);
+        targetNode = new DiscoveryNode(in);
+        term = in.readLong();
+        lastAcceptedTerm = in.readLong();
+        lastAcceptedVersion = in.readLong();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        sourceNode.writeTo(out);
+        targetNode.writeTo(out);
+        out.writeLong(term);
+        out.writeLong(lastAcceptedTerm);
+        out.writeLong(lastAcceptedVersion);
+    }
+
+    public DiscoveryNode getSourceNode() {
+        return sourceNode;
+    }
+
+    public DiscoveryNode getTargetNode() {
+        return targetNode;
+    }
+
+    public long getLastAcceptedVersion() {
+        return lastAcceptedVersion;
+    }
+
+    public long getTerm() {
+        return term;
+    }
+
+    public long getLastAcceptedTerm() {
+        return lastAcceptedTerm;
+    }
+
+    @Override
+    public String toString() {
+        return "Join{" +
+            "term=" + term +
+            ", lastAcceptedTerm=" + lastAcceptedTerm +
+            ", lastAcceptedVersion=" + lastAcceptedVersion +
+            ", sourceNode=" + sourceNode +
+            ", targetNode=" + targetNode +
+            '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Join join = (Join) o;
+
+        if (sourceNode.equals(join.sourceNode) == false) return false;
+        if (targetNode.equals(join.targetNode) == false) return false;
+        if (lastAcceptedVersion != join.lastAcceptedVersion) return false;
+        if (term != join.term) return false;
+        return lastAcceptedTerm == join.lastAcceptedTerm;
+    }
+
+    @Override
+    public int hashCode() {
+        int result = (int) (lastAcceptedVersion ^ (lastAcceptedVersion >>> 32));
+        result = 31 * result + sourceNode.hashCode();
+        result = 31 * result + targetNode.hashCode();
+        result = 31 * result + (int) (term ^ (term >>> 32));
+        result = 31 * result + (int) (lastAcceptedTerm ^ (lastAcceptedTerm >>> 32));
+        return result;
+    }
+}

server/src/main/java/org/elasticsearch/cluster/coordination/PublishRequest.java

@@ -0,0 +1,78 @@
+/*
+ * 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.
+ */
+package org.elasticsearch.cluster.coordination;
+
+import org.elasticsearch.cluster.ClusterState;
+import org.elasticsearch.cluster.node.DiscoveryNode;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.transport.TransportRequest;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Request which is used by the master node to publish cluster state changes.
+ */
+public class PublishRequest extends TransportRequest {
+
+    private final ClusterState acceptedState;
+
+    public PublishRequest(ClusterState acceptedState) {
+        this.acceptedState = acceptedState;
+    }
+
+    public PublishRequest(StreamInput in, DiscoveryNode localNode) throws IOException {
+        super(in);
+        acceptedState = ClusterState.readFrom(in, localNode);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        acceptedState.writeTo(out);
+    }
+
+    public ClusterState getAcceptedState() {
+        return acceptedState;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof PublishRequest)) return false;
+
+        PublishRequest that = (PublishRequest) o;
+
+        return acceptedState.term() == that.acceptedState.term() &&
+            acceptedState.version() == that.acceptedState.version();
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(acceptedState.term(), acceptedState.version());
+    }
+
+    @Override
+    public String toString() {
+        return "PublishRequest{term=" + acceptedState.term()
+            + ", version=" + acceptedState.version()
+            + ", state=" + acceptedState + '}';
+    }
+}

server/src/main/java/org/elasticsearch/cluster/coordination/PublishResponse.java

@@ -0,0 +1,51 @@
+/*
+ * 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.
+ */
+package org.elasticsearch.cluster.coordination;
+
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * Response to a {@link PublishRequest}, carrying the term and version of the request.
+ */
+public class PublishResponse extends TermVersionResponse {
+
+    public PublishResponse(long term, long version) {
+        super(term, version);
+    }
+
+    public PublishResponse(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+    }
+
+    @Override
+    public String toString() {
+        return "PublishResponse{" +
+            "term=" + term +
+            ", version=" + version +
+            '}';
+    }
+}