[CELEBORN-1731] Support merged kv input for Tez

### What changes were proposed in this pull request?
Add MergedKVInput

### Why are the changes needed?

### Does this PR introduce _any_ user-facing change?

### How was this patch tested?

Closes #2974 from GH-Gloway/1731.

Authored-by: hongguangwei <[email protected]>
Signed-off-by: mingji <[email protected]>

client-tez/tez/src/main/java/org/apache/tez/runtime/library/input/CelebornConcatenatedMergedKeyValueInput.java

@@ -0,0 +1,109 @@
+/**
+ * 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
+ *
+ * <p>http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * <p>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.tez.runtime.library.input;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.apache.hadoop.classification.InterfaceAudience.Public;
+import org.apache.tez.dag.api.GroupInputEdge;
+import org.apache.tez.dag.api.TezUncheckedException;
+import org.apache.tez.runtime.api.*;
+import org.apache.tez.runtime.library.api.KeyValueReader;
+
+/**
+ * Implements a {@link MergedLogicalInput} that merges the incoming inputs (e.g. from a {@link
+ * GroupInputEdge} and provide a unified view of the input. It concatenates all the inputs to
+ * provide a unified view
+ */
+@Public
+public class CelebornConcatenatedMergedKeyValueInput extends MergedLogicalInput {
+  private ConcatenatedMergedKeyValueReader concatenatedMergedKeyValueReader;
+
+  public CelebornConcatenatedMergedKeyValueInput(MergedInputContext context, List<Input> inputs) {
+    super(context, inputs);
+  }
+
+  public class ConcatenatedMergedKeyValueReader extends KeyValueReader {
+    private int currentReaderIndex = 0;
+    private KeyValueReader currentReader;
+
+    @Override
+    public boolean next() throws IOException {
+      while ((currentReader == null) || !currentReader.next()) {
+        if (currentReaderIndex == getInputs().size()) {
+          hasCompletedProcessing();
+          completedProcessing = true;
+          getContext().notifyProgress();
+          return false;
+        }
+        try {
+          Reader reader = getInputs().get(currentReaderIndex).getReader();
+          if (!(reader instanceof KeyValueReader)) {
+            throw new TezUncheckedException(
+                "Expected KeyValueReader. " + "Got: " + reader.getClass().getName());
+          }
+          currentReader = (KeyValueReader) reader;
+          currentReaderIndex++;
+          getContext().notifyProgress();
+        } catch (Exception e) {
+          // An InterruptedException is not expected here since this works off of
+          // underlying readers which take care of throwing IOInterruptedExceptions
+          if (e instanceof IOException) {
+            throw (IOException) e;
+          } else {
+            throw new IOException(e);
+          }
+        }
+      }
+      return true;
+    }
+
+    @Override
+    public Object getCurrentKey() throws IOException {
+      return currentReader.getCurrentKey();
+    }
+
+    @Override
+    public Object getCurrentValue() throws IOException {
+      return currentReader.getCurrentValue();
+    }
+
+    public float getProgress() throws IOException, InterruptedException {
+      return (1.0f) * (currentReaderIndex + 1) / getInputs().size();
+    }
+  }
+
+  /** Provides a {@link KeyValueReader} that iterates over the concatenated input data */
+  @Override
+  public KeyValueReader getReader() throws Exception {
+    concatenatedMergedKeyValueReader = new ConcatenatedMergedKeyValueReader();
+    return concatenatedMergedKeyValueReader;
+  }
+
+  @Override
+  public void setConstituentInputIsReady(Input input) {
+    informInputReady();
+  }
+
+  @Override
+  public float getProgress() throws ProgressFailedException, InterruptedException {
+    try {
+      return concatenatedMergedKeyValueReader.getProgress();
+    } catch (IOException e) {
+      throw new ProgressFailedException("getProgress encountered IOException ", e);
+    }
+  }
+}

client-tez/tez/src/main/java/org/apache/tez/runtime/library/input/CelebornConcatenatedMergedKeyValuesInput.java

@@ -0,0 +1,110 @@
+/**
+ * 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
+ *
+ * <p>http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * <p>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.tez.runtime.library.input;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.apache.hadoop.classification.InterfaceAudience.Public;
+import org.apache.tez.dag.api.GroupInputEdge;
+import org.apache.tez.dag.api.TezUncheckedException;
+import org.apache.tez.runtime.api.*;
+import org.apache.tez.runtime.library.api.KeyValuesReader;
+
+/**
+ * Implements a {@link MergedLogicalInput} that merges the incoming inputs (e.g. from a {@link
+ * GroupInputEdge} and provide a unified view of the input. It concatenates all the inputs to
+ * provide a unified view
+ */
+@Public
+public class CelebornConcatenatedMergedKeyValuesInput extends MergedLogicalInput {
+
+  private ConcatenatedMergedKeyValuesReader concatenatedMergedKeyValuesReader;
+
+  public CelebornConcatenatedMergedKeyValuesInput(MergedInputContext context, List<Input> inputs) {
+    super(context, inputs);
+  }
+
+  public class ConcatenatedMergedKeyValuesReader extends KeyValuesReader {
+    private int currentReaderIndex = 0;
+    private KeyValuesReader currentReader;
+
+    @Override
+    public boolean next() throws IOException {
+      while ((currentReader == null) || !currentReader.next()) {
+        if (currentReaderIndex == getInputs().size()) {
+          hasCompletedProcessing();
+          completedProcessing = true;
+          getContext().notifyProgress();
+          return false;
+        }
+        try {
+          Reader reader = getInputs().get(currentReaderIndex).getReader();
+          if (!(reader instanceof KeyValuesReader)) {
+            throw new TezUncheckedException(
+                "Expected KeyValuesReader. " + "Got: " + reader.getClass().getName());
+          }
+          currentReader = (KeyValuesReader) reader;
+          currentReaderIndex++;
+          getContext().notifyProgress();
+        } catch (Exception e) {
+          // An InterruptedException is not expected here since this works off of
+          // underlying readers which take care of throwing IOInterruptedExceptions
+          if (e instanceof IOException) {
+            throw (IOException) e;
+          } else {
+            throw new IOException(e);
+          }
+        }
+      }
+      return true;
+    }
+
+    @Override
+    public Object getCurrentKey() throws IOException {
+      return currentReader.getCurrentKey();
+    }
+
+    @Override
+    public Iterable<Object> getCurrentValues() throws IOException {
+      return currentReader.getCurrentValues();
+    }
+
+    public float getProgress() throws IOException, InterruptedException {
+      return (1.0f) * (currentReaderIndex + 1) / getInputs().size();
+    }
+  }
+
+  /** Provides a {@link KeyValuesReader} that iterates over the concatenated input data */
+  @Override
+  public KeyValuesReader getReader() throws Exception {
+    concatenatedMergedKeyValuesReader = new ConcatenatedMergedKeyValuesReader();
+    return concatenatedMergedKeyValuesReader;
+  }
+
+  @Override
+  public void setConstituentInputIsReady(Input input) {
+    informInputReady();
+  }
+
+  @Override
+  public float getProgress() throws ProgressFailedException, InterruptedException {
+    try {
+      return concatenatedMergedKeyValuesReader.getProgress();
+    } catch (IOException e) {
+      throw new ProgressFailedException("getProgress encountered IOException ", e);
+    }
+  }
+}