Reapply "Add Redistribute translation to Samza runner"

This reverts commit ab9af72.

runners/samza/src/main/java/org/apache/beam/runners/samza/translation/RedistributeByKeyTranslator.java

@@ -0,0 +1,64 @@
+/*
+ * 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.samza.translation;
+
+import com.google.auto.service.AutoService;
+import org.apache.beam.model.pipeline.v1.RunnerApi;
+import org.apache.beam.sdk.runners.TransformHierarchy;
+import org.apache.beam.sdk.transforms.PTransform;
+import org.apache.beam.sdk.util.construction.NativeTransforms;
+import org.apache.beam.sdk.util.construction.graph.PipelineNode;
+import org.apache.beam.sdk.util.construction.graph.QueryablePipeline;
+import org.apache.beam.sdk.values.KV;
+import org.apache.beam.sdk.values.PCollection;
+
+/**
+ * Translates Reshuffle transform into Samza's native partitionBy operator, which will partition
+ * each incoming message by the key into a Task corresponding to that key.
+ */
+public class RedistributeByKeyTranslator<K, V>
+    implements TransformTranslator<PTransform<PCollection<KV<K, V>>, PCollection<KV<K, V>>>> {
+
+  private final ReshuffleTranslator<K, V, V> reshuffleTranslator =
+      new ReshuffleTranslator<>("rdstr-");
+
+  @Override
+  public void translate(
+      PTransform<PCollection<KV<K, V>>, PCollection<KV<K, V>>> transform,
+      TransformHierarchy.Node node,
+      TranslationContext ctx) {
+    reshuffleTranslator.translate(transform, node, ctx);
+  }
+
+  @Override
+  public void translatePortable(
+      PipelineNode.PTransformNode transform,
+      QueryablePipeline pipeline,
+      PortableTranslationContext ctx) {
+    reshuffleTranslator.translatePortable(transform, pipeline, ctx);
+  }
+
+  /** Predicate to determine whether a URN is a Samza native transform. */
+  @AutoService(NativeTransforms.IsNativeTransform.class)
+  public static class IsSamzaNativeTransform implements NativeTransforms.IsNativeTransform {
+    @Override
+    public boolean test(RunnerApi.PTransform pTransform) {
+      return false;
+    }
+  }
+}

runners/samza/src/main/java/org/apache/beam/runners/samza/translation/ReshuffleTranslator.java

@@ -42,6 +42,16 @@
 public class ReshuffleTranslator<K, InT, OutT>
     implements TransformTranslator<PTransform<PCollection<KV<K, InT>>, PCollection<KV<K, OutT>>>> {
 
+  private final String prefix;
+
+  ReshuffleTranslator(String prefix) {
+    this.prefix = prefix;
+  }
+
+  ReshuffleTranslator() {
+    this("rshfl-");
+  }
+
   @Override
   public void translate(
       PTransform<PCollection<KV<K, InT>>, PCollection<KV<K, OutT>>> transform,
@@ -60,7 +70,7 @@ public void translate(
             inputStream,
             inputCoder.getKeyCoder(),
             elementCoder,
-            "rshfl-" + ctx.getTransformId(),
+            prefix + ctx.getTransformId(),
             ctx.getPipelineOptions().getMaxSourceParallelism() > 1);
 
     ctx.registerMessageStream(output, outputStream);
@@ -83,7 +93,7 @@ public void translatePortable(
             inputStream,
             ((KvCoder<K, InT>) windowedInputCoder.getValueCoder()).getKeyCoder(),
             windowedInputCoder,
-            "rshfl-" + ctx.getTransformId(),
+            prefix + ctx.getTransformId(),
             ctx.getPipelineOptions().getMaxSourceParallelism() > 1);
 
     ctx.registerMessageStream(outputId, outputStream);

runners/samza/src/main/java/org/apache/beam/runners/samza/translation/SamzaPipelineTranslator.java

@@ -179,6 +179,7 @@ public Map<String, TransformTranslator<?>> getTransformTranslators() {
       return ImmutableMap.<String, TransformTranslator<?>>builder()
           .put(PTransformTranslation.READ_TRANSFORM_URN, new ReadTranslator<>())
           .put(PTransformTranslation.RESHUFFLE_URN, new ReshuffleTranslator<>())
+          .put(PTransformTranslation.REDISTRIBUTE_BY_KEY_URN, new RedistributeByKeyTranslator<>())
           .put(PTransformTranslation.PAR_DO_TRANSFORM_URN, new ParDoBoundMultiTranslator<>())
           .put(PTransformTranslation.GROUP_BY_KEY_TRANSFORM_URN, new GroupByKeyTranslator<>())
           .put(PTransformTranslation.COMBINE_PER_KEY_TRANSFORM_URN, new GroupByKeyTranslator<>())