| /* |
| * 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.tinkerpop.gremlin.spark.process.computer; |
| |
| import com.google.common.base.Optional; |
| import org.apache.commons.configuration.Configuration; |
| import org.apache.spark.api.java.JavaPairRDD; |
| import org.apache.tinkerpop.gremlin.hadoop.structure.HadoopGraph; |
| import org.apache.tinkerpop.gremlin.hadoop.structure.io.HadoopPools; |
| import org.apache.tinkerpop.gremlin.hadoop.structure.io.VertexWritable; |
| import org.apache.tinkerpop.gremlin.process.computer.MapReduce; |
| import org.apache.tinkerpop.gremlin.process.computer.MessageCombiner; |
| import org.apache.tinkerpop.gremlin.process.computer.VertexProgram; |
| import org.apache.tinkerpop.gremlin.process.computer.util.ComputerGraph; |
| import org.apache.tinkerpop.gremlin.spark.process.computer.payload.MessagePayload; |
| import org.apache.tinkerpop.gremlin.spark.process.computer.payload.Payload; |
| import org.apache.tinkerpop.gremlin.spark.process.computer.payload.ViewIncomingPayload; |
| import org.apache.tinkerpop.gremlin.spark.process.computer.payload.ViewOutgoingPayload; |
| import org.apache.tinkerpop.gremlin.spark.process.computer.payload.ViewPayload; |
| import org.apache.tinkerpop.gremlin.structure.util.Attachable; |
| import org.apache.tinkerpop.gremlin.structure.util.detached.DetachedFactory; |
| import org.apache.tinkerpop.gremlin.structure.util.detached.DetachedVertexProperty; |
| import org.apache.tinkerpop.gremlin.structure.util.star.StarGraph; |
| import org.apache.tinkerpop.gremlin.util.iterator.IteratorUtils; |
| import scala.Tuple2; |
| |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Set; |
| |
| /** |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| */ |
| public final class SparkExecutor { |
| |
| private static final String[] EMPTY_ARRAY = new String[0]; |
| |
| private SparkExecutor() { |
| } |
| |
| //////////////////// |
| // VERTEX PROGRAM // |
| //////////////////// |
| |
| public static <M> JavaPairRDD<Object, ViewIncomingPayload<M>> executeVertexProgramIteration( |
| final JavaPairRDD<Object, VertexWritable> graphRDD, |
| final JavaPairRDD<Object, ViewIncomingPayload<M>> viewIncomingRDD, |
| final SparkMemory memory, |
| final Configuration apacheConfiguration) { |
| |
| if (null != viewIncomingRDD) // the graphRDD and the viewRDD must have the same partitioner |
| assert graphRDD.partitioner().get().equals(viewIncomingRDD.partitioner().get()); |
| final JavaPairRDD<Object, ViewOutgoingPayload<M>> viewOutgoingRDD = (((null == viewIncomingRDD) ? |
| graphRDD.mapValues(vertexWritable -> new Tuple2<>(vertexWritable, Optional.<ViewIncomingPayload<M>>absent())) : // first iteration will not have any views or messages |
| graphRDD.leftOuterJoin(viewIncomingRDD)) // every other iteration may have views and messages |
| // for each partition of vertices emit a view and their outgoing messages |
| .mapPartitionsToPair(partitionIterator -> { |
| HadoopPools.initialize(apacheConfiguration); |
| final VertexProgram<M> workerVertexProgram = VertexProgram.<VertexProgram<M>>createVertexProgram(HadoopGraph.open(apacheConfiguration), apacheConfiguration); // each partition(Spark)/worker(TP3) has a local copy of the vertex program (a worker's task) |
| final Set<String> elementComputeKeys = workerVertexProgram.getElementComputeKeys(); // the compute keys as a set |
| final String[] elementComputeKeysArray = elementComputeKeys.size() == 0 ? EMPTY_ARRAY : elementComputeKeys.toArray(new String[elementComputeKeys.size()]); // the compute keys as an array |
| final SparkMessenger<M> messenger = new SparkMessenger<>(); |
| workerVertexProgram.workerIterationStart(memory.asImmutable()); // start the worker |
| return () -> IteratorUtils.map(partitionIterator, vertexViewIncoming -> { |
| final StarGraph.StarVertex vertex = vertexViewIncoming._2()._1().get(); // get the vertex from the vertex writable |
| // drop any computed properties that are cached in memory |
| if (elementComputeKeysArray.length > 0) |
| vertex.dropVertexProperties(elementComputeKeysArray); |
| final boolean hasViewAndMessages = vertexViewIncoming._2()._2().isPresent(); // if this is the first iteration, then there are no views or messages |
| final List<DetachedVertexProperty<Object>> previousView = hasViewAndMessages ? vertexViewIncoming._2()._2().get().getView() : Collections.emptyList(); |
| final List<M> incomingMessages = hasViewAndMessages ? vertexViewIncoming._2()._2().get().getIncomingMessages() : Collections.emptyList(); |
| previousView.forEach(property -> property.attach(Attachable.Method.create(vertex))); // attach the view to the vertex |
| // previousView.clear(); // no longer needed so kill it from memory |
| /// |
| messenger.setVertexAndIncomingMessages(vertex, incomingMessages); // set the messenger with the incoming messages |
| workerVertexProgram.execute(ComputerGraph.vertexProgram(vertex, workerVertexProgram), messenger, memory); // execute the vertex program on this vertex for this iteration |
| // incomingMessages.clear(); // no longer needed so kill it from memory |
| /// |
| final List<DetachedVertexProperty<Object>> nextView = elementComputeKeysArray.length == 0 ? // not all vertex programs have compute keys |
| Collections.emptyList() : |
| IteratorUtils.list(IteratorUtils.map(vertex.properties(elementComputeKeysArray), property -> DetachedFactory.detach(property, true))); |
| final List<Tuple2<Object, M>> outgoingMessages = messenger.getOutgoingMessages(); // get the outgoing messages |
| if (!partitionIterator.hasNext()) |
| workerVertexProgram.workerIterationEnd(memory.asImmutable()); // if no more vertices in the partition, end the worker's iteration |
| return new Tuple2<>(vertex.id(), new ViewOutgoingPayload<>(nextView, outgoingMessages)); |
| }); |
| }, true)); // true means that the partition is preserved |
| // the graphRDD and the viewRDD must have the same partitioner |
| assert graphRDD.partitioner().get().equals(viewOutgoingRDD.partitioner().get()); |
| // "message pass" by reducing on the vertex object id of the view and message payloads |
| final MessageCombiner<M> messageCombiner = VertexProgram.<VertexProgram<M>>createVertexProgram(HadoopGraph.open(apacheConfiguration), apacheConfiguration).getMessageCombiner().orElse(null); |
| final JavaPairRDD<Object, ViewIncomingPayload<M>> newViewIncomingRDD = viewOutgoingRDD |
| .flatMapToPair(tuple -> () -> IteratorUtils.<Tuple2<Object, Payload>>concat( |
| IteratorUtils.of(new Tuple2<>(tuple._1(), tuple._2().getView())), // emit the view payload |
| IteratorUtils.map(tuple._2().getOutgoingMessages().iterator(), message -> new Tuple2<>(message._1(), new MessagePayload<>(message._2()))))) // emit the outgoing message payloads one by one |
| .reduceByKey(graphRDD.partitioner().get(), (a, b) -> { // reduce the view and outgoing messages into a single payload object representing the new view and incoming messages for a vertex |
| if (a instanceof ViewIncomingPayload) { |
| ((ViewIncomingPayload<M>) a).mergePayload(b, messageCombiner); |
| return a; |
| } else if (b instanceof ViewIncomingPayload) { |
| ((ViewIncomingPayload<M>) b).mergePayload(a, messageCombiner); |
| return b; |
| } else { |
| final ViewIncomingPayload<M> c = new ViewIncomingPayload<>(messageCombiner); |
| c.mergePayload(a, messageCombiner); |
| c.mergePayload(b, messageCombiner); |
| return c; |
| } |
| }) |
| .filter(payload -> !(payload._2() instanceof MessagePayload)) // this happens if there is a message to a vertex that does not exist |
| .filter(payload -> !((payload._2() instanceof ViewIncomingPayload) && !((ViewIncomingPayload<M>) payload._2()).hasView())) // this happens if there are many messages to a vertex that does not exist |
| .mapValues(payload -> payload instanceof ViewIncomingPayload ? |
| (ViewIncomingPayload<M>) payload : // this happens if there is a vertex with incoming messages |
| new ViewIncomingPayload<>((ViewPayload) payload)); // this happens if there is a vertex with no incoming messages |
| // the graphRDD and the viewRDD must have the same partitioner |
| assert graphRDD.partitioner().get().equals(newViewIncomingRDD.partitioner().get()); |
| newViewIncomingRDD |
| .foreachPartition(partitionIterator -> { |
| HadoopPools.initialize(apacheConfiguration); |
| }); // need to complete a task so its BSP and the memory for this iteration is updated |
| return newViewIncomingRDD; |
| } |
| |
| public static <M> JavaPairRDD<Object, VertexWritable> prepareFinalGraphRDD(final JavaPairRDD<Object, VertexWritable> graphRDD, final JavaPairRDD<Object, ViewIncomingPayload<M>> viewIncomingRDD, final String[] elementComputeKeys) { |
| // the graphRDD and the viewRDD must have the same partitioner |
| assert (graphRDD.partitioner().get().equals(viewIncomingRDD.partitioner().get())); |
| // attach the final computed view to the cached graph |
| return graphRDD.leftOuterJoin(viewIncomingRDD) |
| .mapValues(tuple -> { |
| final StarGraph.StarVertex vertex = tuple._1().get(); |
| vertex.dropVertexProperties(elementComputeKeys); |
| final List<DetachedVertexProperty<Object>> view = tuple._2().isPresent() ? tuple._2().get().getView() : Collections.emptyList(); |
| view.forEach(property -> property.attach(Attachable.Method.create(vertex))); |
| // view.clear(); // no longer needed so kill it from memory |
| return tuple._1(); |
| }); |
| } |
| |
| ///////////////// |
| // MAP REDUCE // |
| //////////////// |
| |
| public static <K, V> JavaPairRDD<K, V> executeMap(final JavaPairRDD<Object, VertexWritable> graphRDD, final MapReduce<K, V, ?, ?, ?> mapReduce, final Configuration apacheConfiguration) { |
| JavaPairRDD<K, V> mapRDD = graphRDD.mapPartitionsToPair(partitionIterator -> { |
| HadoopPools.initialize(apacheConfiguration); |
| return () -> new MapIterator<>(MapReduce.<MapReduce<K, V, ?, ?, ?>>createMapReduce(HadoopGraph.open(apacheConfiguration), apacheConfiguration), partitionIterator); |
| }); |
| if (mapReduce.getMapKeySort().isPresent()) |
| mapRDD = mapRDD.sortByKey(mapReduce.getMapKeySort().get(), true, 1); |
| return mapRDD; |
| } |
| |
| public static <K, V, OK, OV> JavaPairRDD<OK, OV> executeCombine(final JavaPairRDD<K, V> mapRDD, final Configuration apacheConfiguration) { |
| return mapRDD.mapPartitionsToPair(partitionIterator -> { |
| HadoopPools.initialize(apacheConfiguration); |
| return () -> new CombineIterator<>(MapReduce.<MapReduce<K, V, OK, OV, ?>>createMapReduce(HadoopGraph.open(apacheConfiguration), apacheConfiguration), partitionIterator); |
| }); |
| } |
| |
| public static <K, V, OK, OV> JavaPairRDD<OK, OV> executeReduce(final JavaPairRDD<K, V> mapOrCombineRDD, final MapReduce<K, V, OK, OV, ?> mapReduce, final Configuration apacheConfiguration) { |
| JavaPairRDD<OK, OV> reduceRDD = mapOrCombineRDD.groupByKey().mapPartitionsToPair(partitionIterator -> { |
| HadoopPools.initialize(apacheConfiguration); |
| return () -> new ReduceIterator<>(MapReduce.<MapReduce<K, V, OK, OV, ?>>createMapReduce(HadoopGraph.open(apacheConfiguration), apacheConfiguration), partitionIterator); |
| }); |
| if (mapReduce.getReduceKeySort().isPresent()) |
| reduceRDD = reduceRDD.sortByKey(mapReduce.getReduceKeySort().get(), true, 1); |
| return reduceRDD; |
| } |
| } |
