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https://issues.apache.org/jira/browse/APEXMALHAR-2008?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15190268#comment-15190268
]
ASF GitHub Bot commented on APEXMALHAR-2008:
--------------------------------------------
Github user ishark commented on a diff in the pull request:
https://github.com/apache/incubator-apex-malhar/pull/207#discussion_r55776429
--- Diff:
library/src/main/java/com/datatorrent/lib/io/fs/HDFSInputModule.java ---
@@ -0,0 +1,253 @@
+/**
+ * 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 com.datatorrent.lib.io.fs;
+
+import javax.validation.constraints.Min;
+import javax.validation.constraints.NotNull;
+import javax.validation.constraints.Size;
+
+import org.apache.commons.lang.mutable.MutableLong;
+import org.apache.hadoop.conf.Configuration;
+
+import com.datatorrent.api.Context;
+import com.datatorrent.api.DAG;
+import com.datatorrent.api.Module;
+import com.datatorrent.common.metric.MetricsAggregator;
+import com.datatorrent.common.metric.SingleMetricAggregator;
+import com.datatorrent.common.metric.sum.LongSumAggregator;
+import com.datatorrent.common.partitioner.StatelessPartitioner;
+import com.datatorrent.lib.counters.BasicCounters;
+import com.datatorrent.lib.io.block.AbstractBlockReader.ReaderRecord;
+import com.datatorrent.lib.io.block.BlockMetadata.FileBlockMetadata;
+import com.datatorrent.lib.io.block.BlockReader;
+import com.datatorrent.lib.io.fs.AbstractFileSplitter.FileMetadata;
+import com.datatorrent.lib.io.fs.HDFSFileSplitter.HDFSScanner;
+import com.datatorrent.netlet.util.Slice;
+
+/**
+ * HDFSInputModule is used to read files/list of files (or directory) from
HDFS. <br/>
+ * Module emits, <br/>
+ * 1. FileMetadata 2. BlockMetadata 3. Block Bytes.<br/><br/>
+ * The module reads data in parallel, following parameters can be
configured<br/>
+ * 1. files: list of file(s)/directories to read<br/>
+ * 2. filePatternRegularExp: Files names matching given regex will be
read<br/>
+ * 3. scanIntervalMillis: interval between two scans to discover new files
in input directory<br/>
+ * 4. recursive: if scan recursively input directories<br/>
+ * 5. blockSize: block size used to read input blocks of file<br/>
+ * 6. readersCount: count of readers to read input file<br/>
+ * 7. sequencialFileRead: If emit file blocks in sequence?
+ */
+public class HDFSInputModule implements Module
+{
+
+ @NotNull
+ @Size(min = 1)
+ private String files;
+ private String filePatternRegularExp;
+ @Min(0)
+ private long scanIntervalMillis;
+ private boolean recursive = true;
+ private long blockSize;
+ private boolean sequencialFileRead = false;
+ private int readersCount;
+
+ public final transient ProxyOutputPort<FileMetadata> filesMetadataOutput
= new ProxyOutputPort();
+ public final transient ProxyOutputPort<FileBlockMetadata>
blocksMetadataOutput = new ProxyOutputPort();
+ public final transient ProxyOutputPort<ReaderRecord<Slice>> messages =
new ProxyOutputPort();
+
+ @Override
+ public void populateDAG(DAG dag, Configuration conf)
+ {
+ HDFSFileSplitter fileSplitter = dag.addOperator("FileSplitter", new
HDFSFileSplitter());
+ BlockReader blockReader = dag.addOperator("BlockReader", new
BlockReader());
+
+ dag.addStream("BlockMetadata", fileSplitter.blocksMetadataOutput,
blockReader.blocksMetadataInput);
+
+ filesMetadataOutput.set(fileSplitter.filesMetadataOutput);
+ blocksMetadataOutput.set(blockReader.blocksMetadataOutput);
+ messages.set(blockReader.messages);
+
+ fileSplitter.setSequencialFileRead(sequencialFileRead);
+ if (blockSize != 0) {
+ fileSplitter.setBlockSize(blockSize);
+ }
+
+ HDFSScanner fileScanner = (HDFSScanner)fileSplitter.getScanner();
+ fileScanner.setFiles(files);
+ if (scanIntervalMillis != 0) {
+ fileScanner.setScanIntervalMillis(scanIntervalMillis);
+ }
+ fileScanner.setRecursive(recursive);
+ if (filePatternRegularExp != null) {
+
fileSplitter.getScanner().setFilePatternRegularExp(filePatternRegularExp);
+ }
+
+ blockReader.setUri(files);
+ if (readersCount != 0) {
+ dag.setAttribute(blockReader, Context.OperatorContext.PARTITIONER,
new StatelessPartitioner<BlockReader>(readersCount));
+ }
+
+ MetricsAggregator blockReaderMetrics = new MetricsAggregator();
+ blockReaderMetrics.addAggregators("bytesReadPerSec", new
SingleMetricAggregator[] {new LongSumAggregator()});
+ dag.setAttribute(blockReader,
Context.OperatorContext.METRICS_AGGREGATOR, blockReaderMetrics);
+ dag.setAttribute(blockReader,
Context.OperatorContext.COUNTERS_AGGREGATOR, new
BasicCounters.LongAggregator<MutableLong>());
--- End diff --
Can you use METRICS_AGGREGATOR here? COUNTERS_AGGREGATOR is marked
deprecated.
> Create hdfs file input module
> ------------------------------
>
> Key: APEXMALHAR-2008
> URL: https://issues.apache.org/jira/browse/APEXMALHAR-2008
> Project: Apache Apex Malhar
> Issue Type: Task
> Reporter: Priyanka Gugale
> Assignee: Priyanka Gugale
> Priority: Minor
> Original Estimate: 72h
> Remaining Estimate: 72h
>
> To read HDFS files in parallel using Apex we normally use FileSplitter and
> FileReader module. It would be a good idea to combine those operators as a
> unit in module. Having a module will give us readily usable set of operators
> to read HDFS files.
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