Java tutorial
/* * 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.beam.runners.flink.translation.functions; import static com.google.common.base.Preconditions.checkArgument; import com.google.auto.value.AutoValue; import com.google.common.collect.ImmutableMap; import com.google.common.collect.ImmutableMultimap; import com.google.common.collect.Multimap; import java.io.ByteArrayInputStream; import java.io.IOException; import java.util.List; import java.util.Map; import javax.annotation.Nullable; import org.apache.beam.model.pipeline.v1.RunnerApi; import org.apache.beam.model.pipeline.v1.RunnerApi.ExecutableStagePayload.SideInputId; import org.apache.beam.runners.core.construction.PTransformTranslation; import org.apache.beam.runners.core.construction.graph.ExecutableStage; import org.apache.beam.runners.core.construction.graph.PipelineNode.PCollectionNode; import org.apache.beam.runners.core.construction.graph.SideInputReference; import org.apache.beam.runners.fnexecution.state.StateRequestHandler; import org.apache.beam.runners.fnexecution.state.StateRequestHandlers.SideInputHandler; import org.apache.beam.runners.fnexecution.state.StateRequestHandlers.SideInputHandlerFactory; import org.apache.beam.sdk.coders.Coder; import org.apache.beam.sdk.coders.KvCoder; import org.apache.beam.sdk.transforms.Materializations; import org.apache.beam.sdk.transforms.windowing.BoundedWindow; import org.apache.beam.sdk.util.WindowedValue; import org.apache.beam.sdk.values.KV; import org.apache.flink.api.common.functions.RuntimeContext; /** * {@link StateRequestHandler} that uses a Flink {@link RuntimeContext} to access Flink broadcast * variable that represent side inputs. */ class FlinkBatchSideInputHandlerFactory implements SideInputHandlerFactory { // Map from side input id to global PCollection id. private final Map<SideInputId, PCollectionNode> sideInputToCollection; private final RuntimeContext runtimeContext; /** * Creates a new state handler for the given stage. Note that this requires a traversal of the * stage itself, so this should only be called once per stage rather than once per bundle. */ static FlinkBatchSideInputHandlerFactory forStage(ExecutableStage stage, RuntimeContext runtimeContext) { ImmutableMap.Builder<SideInputId, PCollectionNode> sideInputBuilder = ImmutableMap.builder(); for (SideInputReference sideInput : stage.getSideInputs()) { sideInputBuilder.put(SideInputId.newBuilder().setTransformId(sideInput.transform().getId()) .setLocalName(sideInput.localName()).build(), sideInput.collection()); } return new FlinkBatchSideInputHandlerFactory(sideInputBuilder.build(), runtimeContext); } private FlinkBatchSideInputHandlerFactory(Map<SideInputId, PCollectionNode> sideInputToCollection, RuntimeContext runtimeContext) { this.sideInputToCollection = sideInputToCollection; this.runtimeContext = runtimeContext; } @Override public <T, V, W extends BoundedWindow> SideInputHandler<V, W> forSideInput(String transformId, String sideInputId, RunnerApi.FunctionSpec accessPattern, Coder<T> elementCoder, Coder<W> windowCoder) { PCollectionNode collectionNode = sideInputToCollection .get(SideInputId.newBuilder().setTransformId(transformId).setLocalName(sideInputId).build()); checkArgument(collectionNode != null, "No side input for %s/%s", transformId, sideInputId); if (PTransformTranslation.ITERABLE_SIDE_INPUT.equals(accessPattern.getUrn())) { @SuppressWarnings("unchecked") // T == V Coder<V> outputCoder = (Coder<V>) elementCoder; return forIterableSideInput(runtimeContext.getBroadcastVariable(collectionNode.getId()), outputCoder, windowCoder); } else if (PTransformTranslation.MULTIMAP_SIDE_INPUT.equals(accessPattern.getUrn()) || Materializations.MULTIMAP_MATERIALIZATION_URN.equals(accessPattern.getUrn())) { // TODO: Remove non standard URN. // Using non standard version of multimap urn as dataflow uses the non standard urn. @SuppressWarnings("unchecked") // T == KV<?, V> KvCoder<?, V> kvCoder = (KvCoder<?, V>) elementCoder; return forMultimapSideInput(runtimeContext.getBroadcastVariable(collectionNode.getId()), kvCoder.getKeyCoder(), kvCoder.getValueCoder(), windowCoder); } else { throw new IllegalArgumentException( String.format("Unknown side input access pattern: %s", accessPattern)); } } private <T, W extends BoundedWindow> SideInputHandler<T, W> forIterableSideInput( List<WindowedValue<T>> broadcastVariable, Coder<T> elementCoder, Coder<W> windowCoder) { ImmutableMultimap.Builder<Object, T> windowToValuesBuilder = ImmutableMultimap.builder(); for (WindowedValue<T> windowedValue : broadcastVariable) { for (BoundedWindow boundedWindow : windowedValue.getWindows()) { @SuppressWarnings("unchecked") W window = (W) boundedWindow; windowToValuesBuilder.put(windowCoder.structuralValue(window), windowedValue.getValue()); } } ImmutableMultimap<Object, T> windowToValues = windowToValuesBuilder.build(); return new SideInputHandler<T, W>() { @Override public Iterable<T> get(byte[] key, W window) { return windowToValues.get(windowCoder.structuralValue(window)); } @Override public Coder<T> resultCoder() { return elementCoder; } }; } private <K, V, W extends BoundedWindow> SideInputHandler<V, W> forMultimapSideInput( List<WindowedValue<KV<K, V>>> broadcastVariable, Coder<K> keyCoder, Coder<V> valueCoder, Coder<W> windowCoder) { ImmutableMultimap.Builder<SideInputKey, V> multimap = ImmutableMultimap.builder(); for (WindowedValue<KV<K, V>> windowedValue : broadcastVariable) { K key = windowedValue.getValue().getKey(); V value = windowedValue.getValue().getValue(); for (BoundedWindow boundedWindow : windowedValue.getWindows()) { @SuppressWarnings("unchecked") W window = (W) boundedWindow; multimap.put(SideInputKey.of(keyCoder.structuralValue(key), windowCoder.structuralValue(window)), value); } } return new MultimapSideInputHandler<>(multimap.build(), keyCoder, valueCoder, windowCoder); } private static class MultimapSideInputHandler<K, V, W extends BoundedWindow> implements SideInputHandler<V, W> { private final Multimap<SideInputKey, V> collection; private final Coder<K> keyCoder; private final Coder<V> valueCoder; private final Coder<W> windowCoder; private MultimapSideInputHandler(Multimap<SideInputKey, V> collection, Coder<K> keyCoder, Coder<V> valueCoder, Coder<W> windowCoder) { this.collection = collection; this.keyCoder = keyCoder; this.valueCoder = valueCoder; this.windowCoder = windowCoder; } @Override public Iterable<V> get(byte[] keyBytes, W window) { K key; try { // TODO: We could skip decoding and just compare encoded values for deterministic keyCoders. key = keyCoder.decode(new ByteArrayInputStream(keyBytes)); } catch (IOException e) { throw new RuntimeException(e); } return collection .get(SideInputKey.of(keyCoder.structuralValue(key), windowCoder.structuralValue(window))); } @Override public Coder<V> resultCoder() { return valueCoder; } } @AutoValue abstract static class SideInputKey { static SideInputKey of(Object key, Object window) { return new AutoValue_FlinkBatchSideInputHandlerFactory_SideInputKey(key, window); } @Nullable abstract Object key(); abstract Object window(); } }