org.apache.hadoop.util.ReadWriteDiskValidator Maven / Gradle / Ivy
/**
* 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.hadoop.util;
import org.apache.hadoop.util.DiskChecker.DiskErrorException;
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Arrays;
import java.util.Random;
import java.util.concurrent.TimeUnit;
/**
* ReadWriteDiskValidator is the class to check a directory by to create a file,
* write some bytes into it, read back, and verify if they are identical.
* Read time and write time are recorded and put into an
* {@link ReadWriteDiskValidatorMetrics}.
*/
public class ReadWriteDiskValidator implements DiskValidator {
public static final String NAME = "read-write";
private static final Random RANDOM = new Random();
@Override
public void checkStatus(File dir) throws DiskErrorException {
ReadWriteDiskValidatorMetrics metric =
ReadWriteDiskValidatorMetrics.getMetric(dir.toString());
Path tmpFile = null;
try {
if (!dir.isDirectory()) {
metric.diskCheckFailed();
throw new DiskErrorException(dir + " is not a directory!");
}
// check the directory presence and permission.
DiskChecker.checkDir(dir);
// create a tmp file under the dir
tmpFile = Files.createTempFile(dir.toPath(), "test", "tmp");
// write 16 bytes into the tmp file
byte[] inputBytes = new byte[16];
RANDOM.nextBytes(inputBytes);
long startTime = System.nanoTime();
Files.write(tmpFile, inputBytes);
long writeLatency = TimeUnit.MICROSECONDS.convert(
System.nanoTime() - startTime, TimeUnit.NANOSECONDS);
metric.addWriteFileLatency(writeLatency);
// read back
startTime = System.nanoTime();
byte[] outputBytes = Files.readAllBytes(tmpFile);
long readLatency = TimeUnit.MICROSECONDS.convert(
System.nanoTime() - startTime, TimeUnit.NANOSECONDS);
metric.addReadFileLatency(readLatency);
// validation
if (!Arrays.equals(inputBytes, outputBytes)) {
metric.diskCheckFailed();
throw new DiskErrorException("Data in file has been corrupted.");
}
} catch (IOException e) {
metric.diskCheckFailed();
throw new DiskErrorException("Disk Check failed!", e);
} finally {
// delete the file
if (tmpFile != null) {
try {
Files.delete(tmpFile);
} catch (IOException e) {
metric.diskCheckFailed();
throw new DiskErrorException("File deletion failed!", e);
}
}
}
}
}