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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLINK-2168) Add HBaseTableSource
Date Thu, 19 Jan 2017 04:20:26 GMT

    [ https://issues.apache.org/jira/browse/FLINK-2168?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15829295#comment-15829295
] 

ASF GitHub Bot commented on FLINK-2168:
---------------------------------------

Github user ramkrish86 commented on a diff in the pull request:

    https://github.com/apache/flink/pull/3149#discussion_r96790136
  
    --- Diff: flink-connectors/flink-hbase/src/main/java/org/apache/flink/addons/hbase/HBaseTableSourceInputFormat.java
---
    @@ -0,0 +1,322 @@
    +/*
    + * 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.flink.addons.hbase;
    +
    +import org.apache.flink.api.common.io.InputFormat;
    +import org.apache.flink.api.common.io.LocatableInputSplitAssigner;
    +import org.apache.flink.api.common.io.RichInputFormat;
    +import org.apache.flink.api.common.io.statistics.BaseStatistics;
    +import org.apache.flink.api.common.typeinfo.TypeInformation;
    +import org.apache.flink.api.java.typeutils.ResultTypeQueryable;
    +import org.apache.flink.api.java.typeutils.RowTypeInfo;
    +import org.apache.flink.configuration.Configuration;
    +import org.apache.flink.core.io.InputSplitAssigner;
    +import org.apache.flink.types.Row;
    +import org.apache.hadoop.hbase.HBaseConfiguration;
    +import org.apache.hadoop.hbase.TableName;
    +import org.apache.hadoop.hbase.TableNotFoundException;
    +import org.apache.hadoop.hbase.client.Scan;
    +import org.apache.hadoop.hbase.client.Table;
    +import org.apache.hadoop.hbase.client.ClusterConnection;
    +import org.apache.hadoop.hbase.client.Result;
    +import org.apache.hadoop.hbase.client.ResultScanner;
    +import org.apache.hadoop.hbase.client.ConnectionFactory;
    +import org.apache.hadoop.hbase.client.Connection;
    +import org.apache.hadoop.hbase.client.HRegionLocator;
    +import org.apache.hadoop.hbase.util.Bytes;
    +import org.apache.hadoop.hbase.util.Pair;
    +import org.slf4j.Logger;
    +import org.slf4j.LoggerFactory;
    +
    +import java.io.IOException;
    +import java.math.BigDecimal;
    +import java.math.BigInteger;
    +import java.util.ArrayList;
    +import java.util.Date;
    +import java.util.List;
    +
    +/**
    + * {@link InputFormat} subclass that wraps the access for HTables. Returns the result
as {@link Row}
    + */
    +public class HBaseTableSourceInputFormat extends RichInputFormat<Row, TableInputSplit>
implements ResultTypeQueryable<Row> {
    +
    +	private static final long serialVersionUID = 1L;
    +
    +	private static final Logger LOG = LoggerFactory.getLogger(HBaseTableSourceInputFormat.class);
    +	private String tableName;
    +	private TypeInformation[] fieldTypeInfos;
    +	private String[] fieldNames;
    +	private transient Table table;
    +	private transient Scan scan;
    +	private transient Connection conn;
    +	private ResultScanner resultScanner = null;
    +
    +	private byte[] lastRow;
    +	private int scannedRows;
    +	private boolean endReached = false;
    +	private org.apache.hadoop.conf.Configuration conf;
    +	private static final String COLON = ":";
    +
    +	public HBaseTableSourceInputFormat(org.apache.hadoop.conf.Configuration conf, String
tableName, String[] fieldNames, TypeInformation[] fieldTypeInfos) {
    +		this.conf = conf;
    +		this.tableName = tableName;
    +		this.fieldNames = fieldNames;
    +		this.fieldTypeInfos = fieldTypeInfos;
    +	}
    +
    +	@Override
    +	public void configure(Configuration parameters) {
    +		LOG.info("Initializing HBaseConfiguration");
    +		connectToTable();
    +		if(table != null) {
    +			scan = createScanner();
    +		}
    +	}
    +
    +	private Scan createScanner() {
    +		Scan scan = new Scan();
    +		for(String field : fieldNames) {
    +			// select only the fields in the 'selectedFields'
    +			String[] famCol = field.split(COLON);
    +			scan.addColumn(Bytes.toBytes(famCol[0]), Bytes.toBytes(famCol[1]));
    +		}
    +		return scan;
    +	}
    +
    +	private void connectToTable() {
    +		//use files found in the classpath
    +		if(this.conf == null) {
    +			this.conf = HBaseConfiguration.create();
    +		}
    +		try {
    +			conn = ConnectionFactory.createConnection(this.conf);
    +		} catch(IOException ioe) {
    +			LOG.error("Exception while creating connection to hbase cluster", ioe);
    +			return;
    +		}
    +		try {
    +			table = conn.getTable(TableName.valueOf(tableName));
    +		} catch(TableNotFoundException tnfe) {
    +			LOG.error("The table " + tableName + " not found ", tnfe);
    +		} catch(IOException ioe) {
    +			LOG.error("Exception while connecting to the table "+tableName+ " ", ioe);
    +		}
    +	}
    +
    +	@Override
    +	public BaseStatistics getStatistics(BaseStatistics cachedStatistics) throws IOException
{
    +		return null;
    +	}
    +
    +	@Override
    +	public TableInputSplit[] createInputSplits(final int minNumSplits) throws IOException
{
    +		if (table == null) {
    +			throw new IOException("The HBase table has not been opened!");
    +		}
    +		if (scan == null) {
    +			throw new IOException("getScanner returned null");
    +		}
    +
    +		//Gets the starting and ending row keys for every region in the currently open table
    +		HRegionLocator regionLocator = new HRegionLocator(table.getName(), (ClusterConnection)
conn);
    +		final Pair<byte[][], byte[][]> keys = regionLocator.getStartEndKeys();
    +		if (keys == null || keys.getFirst() == null || keys.getFirst().length == 0) {
    +			throw new IOException("Expecting at least one region.");
    +		}
    +		final byte[] startRow = scan.getStartRow();
    +		final byte[] stopRow = scan.getStopRow();
    +		final boolean scanWithNoLowerBound = startRow.length == 0;
    +		final boolean scanWithNoUpperBound = stopRow.length == 0;
    +
    +		final List<TableInputSplit> splits = new ArrayList<TableInputSplit>(minNumSplits);
    +		for (int i = 0; i < keys.getFirst().length; i++) {
    +			final byte[] startKey = keys.getFirst()[i];
    +			final byte[] endKey = keys.getSecond()[i];
    +			final String regionLocation = regionLocator.getRegionLocation(startKey, false).getHostnamePort();
    +			//Test if the given region is to be included in the InputSplit while splitting the
regions of a table
    +			if (!includeRegionInSplit(startKey, endKey)) {
    +				continue;
    +			}
    +			//Finds the region on which the given row is being served
    +			final String[] hosts = new String[]{regionLocation};
    +
    +			// determine if regions contains keys used by the scan
    +			boolean isLastRegion = endKey.length == 0;
    +			if ((scanWithNoLowerBound || isLastRegion || Bytes.compareTo(startRow, endKey) <
0) &&
    +				(scanWithNoUpperBound || Bytes.compareTo(stopRow, startKey) > 0)) {
    +
    +				final byte[] splitStart = scanWithNoLowerBound || Bytes.compareTo(startKey, startRow)
>= 0 ? startKey : startRow;
    +				final byte[] splitStop = (scanWithNoUpperBound || Bytes.compareTo(endKey, stopRow)
<= 0)
    +					&& !isLastRegion ? endKey : stopRow;
    +				int id = splits.size();
    +				final TableInputSplit split = new TableInputSplit(id, hosts, table.getName().getName(),
splitStart, splitStop);
    +				splits.add(split);
    +			}
    +		}
    +		LOG.info("Created " + splits.size() + " splits");
    +		for (TableInputSplit split : splits) {
    +			logSplitInfo("created", split);
    +		}
    +		return splits.toArray(new TableInputSplit[0]);
    +	}
    +
    +	protected boolean includeRegionInSplit(final byte[] startKey, final byte[] endKey) {
    +		return true;
    +	}
    +
    +	@Override
    +	public InputSplitAssigner getInputSplitAssigner(TableInputSplit[] inputSplits) {
    +		return new LocatableInputSplitAssigner(inputSplits);
    +	}
    +
    +	@Override
    +	public void open(TableInputSplit split) throws IOException {
    +		if (table == null) {
    +			throw new IOException("The HBase table has not been opened!");
    +		}
    +		if (scan == null) {
    +			throw new IOException("getScanner returned null");
    +		}
    +		if (split == null) {
    +			throw new IOException("Input split is null!");
    +		}
    +
    +		logSplitInfo("opening", split);
    +		// set the start row and stop row from the splits
    +		scan.setStartRow(split.getStartRow());
    +		lastRow = split.getEndRow();
    +		scan.setStopRow(lastRow);
    +
    +		resultScanner = table.getScanner(scan);
    +		endReached = false;
    +		scannedRows = 0;
    +	}
    +
    +	private void logSplitInfo(String action, TableInputSplit split) {
    +		int splitId = split.getSplitNumber();
    +		String splitStart = Bytes.toString(split.getStartRow());
    +		String splitEnd = Bytes.toString(split.getEndRow());
    +		String splitStartKey = splitStart.isEmpty() ? "-" : splitStart;
    +		String splitStopKey = splitEnd.isEmpty() ? "-" : splitEnd;
    +		String[] hostnames = split.getHostnames();
    +		LOG.info("{} split (this={})[{}|{}|{}|{}]", action, this, splitId, hostnames, splitStartKey,
splitStopKey);
    +	}
    +
    +	@Override
    +	public boolean reachedEnd() throws IOException {
    +		return endReached;
    +	}
    +
    +	@Override
    +	public Row nextRecord(Row reuse) throws IOException {
    +		if (resultScanner == null) {
    +			throw new IOException("No table result scanner provided!");
    +		}
    +		try {
    +			Result res = resultScanner.next();
    +			if (res != null) {
    +				scannedRows++;
    +				lastRow = res.getRow();
    +				return mapResultToRow(res);
    +			}
    +		} catch (Exception e) {
    +			resultScanner.close();
    +			//workaround for timeout on scan
    +			LOG.warn("Error after scan of " + scannedRows + " rows. Retry with a new scanner...",
e);
    +			scan.setStartRow(lastRow);
    +			resultScanner = table.getScanner(scan);
    +			Result res = resultScanner.next();
    +			if (res != null) {
    +				scannedRows++;
    +				lastRow = res.getRow();
    +				return mapResultToRow(res);
    +			}
    +		}
    +		endReached = true;
    +		return null;
    +	}
    +
    +	private Row mapResultToRow(Result res) {
    +		Object[] values = new Object[fieldNames.length];
    +		int i = 0;
    +		for(String field : fieldNames) {
    +			String[] famCol = field.split(COLON);
    +			byte[] value = res.getValue(Bytes.toBytes(famCol[0]), Bytes.toBytes(famCol[1]));
    +			TypeInformation typeInfo = fieldTypeInfos[i];
    +			if(typeInfo.isBasicType()) {
    +				if(typeInfo.getTypeClass() ==  Integer.class) {
    +					values[i] = Bytes.toInt(value);
    +				} else if(typeInfo.getTypeClass() == Short.class) {
    +					values[i] = Bytes.toShort(value);
    +				} else if(typeInfo.getTypeClass() == Float.class) {
    +					values[i] = Bytes.toFloat(value);
    +				} else if(typeInfo.getTypeClass() == Long.class) {
    +					values[i] = Bytes.toLong(value);
    +				} else if(typeInfo.getTypeClass() == String.class) {
    +					values[i] = Bytes.toString(value);
    +				} else if(typeInfo.getTypeClass() == Byte.class) {
    +					values[i] = value[0];
    +				} else if(typeInfo.getTypeClass() == Boolean.class) {
    +					values[i] = Bytes.toBoolean(value);
    +				} else if(typeInfo.getTypeClass() == Double.class) {
    +					values[i] = Bytes.toDouble(value);
    +				} else if(typeInfo.getTypeClass() == BigInteger.class) {
    +					values[i] = new BigInteger(value);
    +				} else if(typeInfo.getTypeClass() == BigDecimal.class) {
    +					values[i] = Bytes.toBigDecimal(value);
    +				} else if(typeInfo.getTypeClass() == Date.class) {
    +					values[i] = new Date(Bytes.toLong(value));
    +				}
    +			} else {
    +				// TODO for other types??
    --- End diff --
    
    I can see that in the TableSourceITCase that uses CsvInputFormat - the metadata is also
passed as the input and the meta data is registered with the table. Now in cases like hbase
- how should that be done? 


> Add HBaseTableSource
> --------------------
>
>                 Key: FLINK-2168
>                 URL: https://issues.apache.org/jira/browse/FLINK-2168
>             Project: Flink
>          Issue Type: New Feature
>          Components: Table API & SQL
>    Affects Versions: 0.9
>            Reporter: Fabian Hueske
>            Assignee: ramkrishna.s.vasudevan
>            Priority: Minor
>              Labels: starter
>
> Add a {{HBaseTableSource}} to read data from a HBase table. The {{HBaseTableSource}}
should implement the {{ProjectableTableSource}} (FLINK-3848) and {{FilterableTableSource}}
(FLINK-3849) interfaces.
> The implementation can be based on Flink's {{TableInputFormat}}.



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