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Client interface into HPCC Systems' Distributed File System.
/*******************************************************************************
* HPCC SYSTEMS software Copyright (C) 2018 HPCC Systems®.
*
* Licensed 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.hpccsystems.dfs.client;
import org.hpccsystems.commons.ecl.FieldDef;
import org.hpccsystems.commons.ecl.RecordDefinitionTranslator;
import org.hpccsystems.commons.errors.HpccFileException;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;
import java.io.IOException;
import java.util.Iterator;
/**
* Remote file reader the reads the data represented by a @see org.hpccsystems.dfs.client.DataPartition
* Remote file reader the reads the data represented by a @see org.hpccsystems.dfs.client.DataPartition
* and constructs records via the provided @see org.hpccsystems.dfs.client#IRecordBuilder.
*/
public class HpccRemoteFileReader implements Iterator
{
private static final Logger log = LogManager.getLogger(HpccRemoteFileReader.class);
private FieldDef originalRecordDef = null;
private DataPartition dataPartition = null;
private RowServiceInputStream inputStream = null;
private BinaryRecordReader binaryRecordReader;
private IRecordBuilder recordBuilder = null;
private boolean handlePrefetch = true;
private boolean isClosed = false;
private boolean canReadNext = true;
private long openTimeMs = 0;
private long recordsRead = 0;
public static final int NO_RECORD_LIMIT = -1;
public static final int DEFAULT_READ_SIZE_OPTION = -1;
public static final int DEFAULT_CONNECT_TIMEOUT_OPTION = -1;
public static class FileReadResumeInfo
{
public long inputStreamPos = 0;
public byte[] tokenBin = null;
public long recordReaderStreamPos = 0;
};
/**
* Instantiates a new hpcc remote file reader.
*
* @param dp
* the dp
* @param originalRD
* the original RD
* @param recBuilder
* the rec builder
* @throws Exception
* the exception
*/
public HpccRemoteFileReader(DataPartition dp, FieldDef originalRD, IRecordBuilder recBuilder) throws Exception
{
this(dp,originalRD,recBuilder,DEFAULT_CONNECT_TIMEOUT_OPTION);
}
/**
* A remote file reader that reads the part identified by the HpccPart object using the record definition provided.
*
* @param dp
* the part of the file, name and location
* @param originalRD
* the record defintion for the dataset
* @param recBuilder
* the IRecordBuilder used to construct records
* @param connectTimeout
* the connection timeout in seconds, -1 for default
* @throws Exception
* the exception
*/
public HpccRemoteFileReader(DataPartition dp, FieldDef originalRD, IRecordBuilder recBuilder, int connectTimeout) throws Exception
{
this(dp, originalRD, recBuilder, connectTimeout, NO_RECORD_LIMIT);
}
/**
* A remote file reader that reads the part identified by the HpccPart object using the record definition provided.
*
* @param dp
* the part of the file, name and location
* @param originalRD
* the record defintion for the dataset
* @param recBuilder
* the IRecordBuilder used to construct records
* @param connectTimeout
* the connection timeout in milliseconds, -1 for default
* @param limit
* the maximum number of records to read from the provided data partition, -1 specifies no limit
* @throws Exception
* general exception
*/
public HpccRemoteFileReader(DataPartition dp, FieldDef originalRD, IRecordBuilder recBuilder, int connectTimeout, int limit) throws Exception
{
this(dp, originalRD, recBuilder, connectTimeout, limit, true, DEFAULT_READ_SIZE_OPTION);
}
/**
* A remote file reader that reads the part identified by the HpccPart object using the record definition provided.
*
* @param dp
* the part of the file, name and location
* @param originalRD
* the record defintion for the dataset
* @param recBuilder
* the IRecordBuilder used to construct records
* @param connectTimeout
* the connection timeout in seconds, -1 for default
* @param limit
* the maximum number of records to read from the provided data partition, -1 specifies no limit
* @param createPrefetchThread
* the input stream should create and manage prefetching on its own thread. If false prefetch needs to be called on another thread periodically.
* @param readSizeKB
* read request size in KB, -1 specifies use default value
* @throws Exception
* general exception
*/
public HpccRemoteFileReader(DataPartition dp, FieldDef originalRD, IRecordBuilder recBuilder, int connectTimeout, int limit, boolean createPrefetchThread, int readSizeKB) throws Exception
{
this(dp, originalRD, recBuilder, connectTimeout, limit, createPrefetchThread, readSizeKB, null);
}
/**
* A remote file reader that reads the part identified by the HpccPart object using the record definition provided.
*
* @param dp
* the part of the file, name and location
* @param originalRD
* the record defintion for the dataset
* @param recBuilder
* the IRecordBuilder used to construct records
* @param connectTimeout
* the connection timeout in seconds, -1 for default
* @param limit
* the maximum number of records to read from the provided data partition, -1 specifies no limit
* @param createPrefetchThread
* the input stream should create and manage prefetching on its own thread. If false prefetch needs to be called on another thread periodically.
* @param readSizeKB
* read request size in KB, -1 specifies use default value
* @param resumeInfo
* FileReadeResumeInfo data required to restart a read from a particular point in a file
* @throws Exception
* general exception
*/
public HpccRemoteFileReader(DataPartition dp, FieldDef originalRD, IRecordBuilder recBuilder, int connectTimeout, int limit, boolean createPrefetchThread, int readSizeKB, FileReadResumeInfo resumeInfo) throws Exception
{
this(dp, originalRD, recBuilder, connectTimeout, limit, createPrefetchThread, readSizeKB, resumeInfo, RowServiceInputStream.DEFAULT_SOCKET_OP_TIMEOUT_MS);
}
/**
* A remote file reader that reads the part identified by the HpccPart object using the record definition provided.
*
* @param dp
* the part of the file, name and location
* @param originalRD
* the record defintion for the dataset
* @param recBuilder
* the IRecordBuilder used to construct records
* @param connectTimeout
* the connection timeout in milliseconds, -1 for default
* @param limit
* the maximum number of records to read from the provided data partition, -1 specifies no limit
* @param createPrefetchThread
* the input stream should create and manage prefetching on its own thread. If false prefetch needs to be called on another thread periodically.
* @param readSizeKB
* read request size in KB, -1 specifies use default value
* @param resumeInfo
* FileReadeResumeInfo data required to restart a read from a particular point in a file, null for reading from start
* @param socketOpTimeoutMs
* Socket (read / write) operation timeout in milliseconds
* @throws Exception
* general exception
*/
public HpccRemoteFileReader(DataPartition dp, FieldDef originalRD, IRecordBuilder recBuilder, int connectTimeout, int limit, boolean createPrefetchThread, int readSizeKB, FileReadResumeInfo resumeInfo, int socketOpTimeoutMs) throws Exception
{
this.handlePrefetch = createPrefetchThread;
this.originalRecordDef = originalRD;
if (this.originalRecordDef == null)
{
throw new Exception("HpccRemoteFileReader: Original record definition is null.");
}
if (connectTimeout < 1)
{
connectTimeout = RowServiceInputStream.DEFAULT_CONNECT_TIMEOUT_MILIS;
}
this.dataPartition = dp;
this.recordBuilder = recBuilder;
FieldDef projectedRecordDefinition = recBuilder.getRecordDefinition();
if (projectedRecordDefinition == null)
{
throw new Exception("IRecordBuilder does not have a valid record definition.");
}
if (resumeInfo == null)
{
this.inputStream = new RowServiceInputStream(this.dataPartition, this.originalRecordDef, projectedRecordDefinition, connectTimeout, limit, createPrefetchThread, readSizeKB, null, false, socketOpTimeoutMs);
this.binaryRecordReader = new BinaryRecordReader(this.inputStream);
this.binaryRecordReader.initialize(this.recordBuilder);
if (dp.getFileType() == DataPartition.FileType.INDEX)
{
this.binaryRecordReader.setIsIndex(true);
}
}
else
{
RowServiceInputStream.RestartInformation restartInfo = new RowServiceInputStream.RestartInformation();
restartInfo.streamPos = resumeInfo.inputStreamPos;
restartInfo.tokenBin = resumeInfo.tokenBin;
this.inputStream = new RowServiceInputStream(this.dataPartition, this.originalRecordDef, projectedRecordDefinition, connectTimeout, limit, createPrefetchThread, readSizeKB, restartInfo, false, socketOpTimeoutMs);
long bytesToSkip = resumeInfo.recordReaderStreamPos - resumeInfo.inputStreamPos;
if (bytesToSkip < 0)
{
throw new Exception("Unable to restart unexpected stream pos in record reader.");
}
this.inputStream.skip(bytesToSkip);
this.binaryRecordReader = new BinaryRecordReader(this.inputStream, resumeInfo.recordReaderStreamPos);
this.binaryRecordReader.initialize(this.recordBuilder);
}
log.info("HPCCRemoteFileReader: Opening file part: " + dataPartition.getThisPart()
+ (resumeInfo != null ? " resume position: " + resumeInfo.inputStreamPos : "" ));
log.trace("Original record definition:\n"
+ RecordDefinitionTranslator.toJsonRecord(originalRD)
+ " projected record definition:\n"
+ RecordDefinitionTranslator.toJsonRecord(projectedRecordDefinition));
openTimeMs = System.currentTimeMillis();
}
/**
* Returns the stream position within the file.
*
* @return stream position
*/
public long getStreamPosition()
{
return this.binaryRecordReader.getStreamPosAfterLastRecord();
}
/**
* Returns read resume info for the current position within the file.
*
* @return FileReadResumeInfo
*/
public FileReadResumeInfo getFileReadResumeInfo()
{
return getFileReadResumeInfo(this.getStreamPosition());
}
/**
* Returns read resume info for the specified position within the file.
*
* @param streamPosition the stream position to resume from
* @return FileReadResumeInfo
*/
public FileReadResumeInfo getFileReadResumeInfo(Long streamPosition)
{
FileReadResumeInfo resumeInfo = new FileReadResumeInfo();
resumeInfo.recordReaderStreamPos = streamPosition;
RowServiceInputStream.RestartInformation isRestartInfo = this.inputStream.getRestartInformationForStreamPos(resumeInfo.recordReaderStreamPos);
resumeInfo.inputStreamPos = isRestartInfo.streamPos;
resumeInfo.tokenBin = isRestartInfo.tokenBin;
return resumeInfo;
}
/**
* Returns the number of messages created during the reading process
*
* @return number of messages created
*/
public int getRemoteReadMessageCount()
{
int count = 0;
if (binaryRecordReader != null)
count = binaryRecordReader.getStreamMessageCount();
return count;
}
/**
* Returns messages created during the file reading process
*
* @return Messages concatenated into a String
*/
public String getRemoteReadMessages()
{
String report = "";
if (binaryRecordReader != null)
report = binaryRecordReader.getStreamMessages();
return report;
}
/**
* Prefetchs more data from the underlying socket. Should only be called on a separate thread from the the consumer thread calling hasNext() / next().
*/
public void prefetch()
{
if (handlePrefetch)
{
log.warn("Prefetch called on an HpccRemoteFileReader that has an internal prefetch thread.");
return;
}
if (isClosed)
{
log.warn("Prefetch called on an HpccRemoteFileReader that has been closed.");
return;
}
this.inputStream.prefetchData();
}
/**
* Is there more data
*
* @return true if there is a next record
*/
@Override
public boolean hasNext()
{
if (isClosed)
{
log.warn("hasNext() called on an HpccRemoteFileReader that has been closed.");
return false;
}
// Keep track of whether we have said there is another record.
// This allows us to handle edge cases around close() being called between hasNext() and next()
canReadNext = false;
try
{
canReadNext = this.binaryRecordReader.hasNext();
// Has next may not catch the prefetch exception if it occurs at the beginning of a read
// This is due to InputStream.hasNext() being allowed to throw an IOException when closed.
if (this.inputStream.getPrefetchException() != null)
{
throw this.inputStream.getPrefetchException();
}
}
catch (HpccFileException e)
{
canReadNext = false;
log.error("Read failure for " + this.dataPartition.toString());
java.util.NoSuchElementException exception = new java.util.NoSuchElementException("Fatal read error: " + e.getMessage());
exception.initCause(e);
throw exception;
}
return canReadNext;
}
/**
* Return next record.
*
* @return the record
*/
@Override
public T next()
{
if (isClosed && !canReadNext)
{
throw new java.util.NoSuchElementException("Fatal read error: Attempting to read next() from a closed file reader.");
}
Object rslt = null;
try
{
rslt = this.binaryRecordReader.getNext();
}
catch (HpccFileException e)
{
log.error("Read failure for " + this.dataPartition.toString() + " " + e.getMessage());
java.util.NoSuchElementException exception = new java.util.NoSuchElementException("Fatal read error: " + e.getMessage());
exception.initCause(e);
throw exception;
}
recordsRead++;
// Reset this after each read so we can handle edge cases where close() was called between hasNext() / next()
canReadNext = false;
return (T) rslt;
}
/**
* Closes inputstream, reports summary of messages generated during read operation.
*
* @throws Exception
* the exception
*/
public void close() throws Exception
{
if (isClosed)
{
log.warn("Calling close on an already closed file reader for file part: " + this.dataPartition.toString());
return;
}
report();
this.inputStream.close();
isClosed = true;
long closeTimeMs = System.currentTimeMillis();
double readTimeS = (closeTimeMs - openTimeMs) / 1000.0;
log.info("HPCCRemoteFileReader: Closing file part: " + dataPartition.getThisPart()
+ " read time: " + readTimeS + "s "
+ " records read: " + recordsRead);
}
/**
* Returns the number of bytes available to read immediately.
*
* @return the available
* @throws IOException
* Signals that an I/O exception has occurred.
*/
public int getAvailable() throws IOException
{
return this.binaryRecordReader.getAvailable();
}
/**
* Returns the RowServiceInputStream used to read the file from dafilesrv
*
* @return the input stream
*/
public RowServiceInputStream getInputStream()
{
return this.inputStream;
}
/**
* Returns the BinaryRecordReader used to construct records
*
* @return the record reader
*/
public BinaryRecordReader getRecordReader()
{
return this.binaryRecordReader;
}
/**
* Reports summary of messages generated during read operation.
*
*/
public void report()
{
if (getRemoteReadMessageCount() > 0)
{
log.warn("DataPartition '" + this.dataPartition + "' read operation messages:\n");
log.warn(getRemoteReadMessages());
}
}
}