/*
* 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.drill.exec.store.text;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.util.List;
import java.util.Map;
import org.apache.drill.exec.memory.BufferAllocator;
import org.apache.drill.exec.store.StorageStrategy;
import org.apache.drill.exec.store.EventBasedRecordWriter.FieldConverter;
import org.apache.drill.exec.store.StringOutputRecordWriter;
import org.apache.drill.exec.vector.complex.reader.FieldReader;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import com.google.common.base.Joiner;
public class DrillTextRecordWriter extends StringOutputRecordWriter {
static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(DrillTextRecordWriter.class);
private final StorageStrategy storageStrategy;
private Path cleanUpLocation;
private String location;
private String prefix;
private String fieldDelimiter;
private String extension;
private static String eol = System.getProperty("line.separator");
private int index;
private PrintStream stream = null;
private FileSystem fs = null;
// Record write status
private boolean fRecordStarted = false; // true once the startRecord() is called until endRecord() is called
private StringBuilder currentRecord; // contains the current record separated by field delimiter
public DrillTextRecordWriter(BufferAllocator allocator, StorageStrategy storageStrategy) {
super(allocator);
this.storageStrategy = storageStrategy == null ? StorageStrategy.DEFAULT : storageStrategy;
}
@Override
public void init(Map<String, String> writerOptions) throws IOException {
this.location = writerOptions.get("location");
this.prefix = writerOptions.get("prefix");
this.fieldDelimiter = writerOptions.get("separator");
this.extension = writerOptions.get("extension");
Configuration conf = new Configuration();
conf.set(FileSystem.FS_DEFAULT_NAME_KEY, writerOptions.get(FileSystem.FS_DEFAULT_NAME_KEY));
this.fs = FileSystem.get(conf);
this.currentRecord = new StringBuilder();
this.index = 0;
}
@Override
public void startNewSchema(List<String> columnNames) throws IOException {
// wrap up the current file
cleanup();
// open a new file for writing data with new schema
Path fileName = new Path(location, prefix + "_" + index + "." + extension);
try {
// drill text writer does not support partitions, so only one file can be created
// and thus only one location should be deleted in case of abort
// to ensure that our writer was the first to create output file,
// we create empty output file first and fail if file exists
cleanUpLocation = storageStrategy.createFileAndApply(fs, fileName);
// since empty output file will be overwritten (some file systems may restrict append option)
// we need to re-apply file permission
DataOutputStream fos = fs.create(fileName);
storageStrategy.applyToFile(fs, fileName);
stream = new PrintStream(fos);
logger.debug("Created file: {}", fileName);
} catch (IOException ex) {
logger.error("Unable to create file: " + fileName, ex);
throw ex;
}
index++;
stream.println(Joiner.on(fieldDelimiter).join(columnNames));
}
@Override
public void addField(int fieldId, String value) throws IOException {
currentRecord.append(value + fieldDelimiter);
}
@Override
public void startRecord() throws IOException {
if (fRecordStarted) {
throw new IOException("Previous record is not written completely");
}
fRecordStarted = true;
}
@Override
public void endRecord() throws IOException {
if (!fRecordStarted) {
throw new IOException("No record is in writing");
}
// remove the extra delimiter at the end
currentRecord.deleteCharAt(currentRecord.length()-fieldDelimiter.length());
stream.println(currentRecord.toString());
// reset current record status
currentRecord.delete(0, currentRecord.length());
fRecordStarted = false;
}
@Override
public FieldConverter getNewMapConverter(int fieldId, String fieldName, FieldReader reader) {
return new ComplexStringFieldConverter(fieldId, fieldName, reader);
}
@Override
public FieldConverter getNewRepeatedMapConverter(int fieldId, String fieldName, FieldReader reader) {
return new ComplexStringFieldConverter(fieldId, fieldName, reader);
}
@Override
public FieldConverter getNewRepeatedListConverter(int fieldId, String fieldName, FieldReader reader) {
return new ComplexStringFieldConverter(fieldId, fieldName, reader);
}
public class ComplexStringFieldConverter extends FieldConverter {
public ComplexStringFieldConverter(int fieldId, String fieldName, FieldReader reader) {
super(fieldId, fieldName, reader);
}
@Override
public void writeField() throws IOException {
addField(fieldId, reader.readObject().toString());
}
}
@Override
public void cleanup() throws IOException {
super.cleanup();
if (stream != null) {
stream.close();
stream = null;
logger.debug("closing file");
}
}
@Override
public void abort() throws IOException {
if (cleanUpLocation != null) {
fs.delete(cleanUpLocation, true);
logger.info("Aborting writer. Location [{}] on file system [{}] is deleted.",
cleanUpLocation.toUri().getPath(), fs.getUri());
}
}
}