/**
* Copyright 2007 The Apache Software Foundation
*
* 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.hbase.util;
import java.io.DataInputStream;
import java.io.IOException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.dfs.DistributedFileSystem;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.FileSystemVersionException;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.RemoteExceptionHandler;
/**
* Utility methods for interacting with the underlying file system.
*/
public class FSUtils {
private static final Log LOG = LogFactory.getLog(FSUtils.class);
/**
* Not instantiable
*/
private FSUtils() {}
/**
* Checks to see if the specified file system is available
*
* @param fs
* @throws IOException
*/
public static void checkFileSystemAvailable(final FileSystem fs)
throws IOException {
if (!(fs instanceof DistributedFileSystem)) {
return;
}
IOException exception = null;
DistributedFileSystem dfs = (DistributedFileSystem) fs;
try {
if (dfs.exists(new Path("/"))) {
return;
}
} catch (IOException e) {
exception = RemoteExceptionHandler.checkIOException(e);
}
try {
fs.close();
} catch (Exception e) {
LOG.error("file system close failed: ", e);
}
IOException io = new IOException("File system is not available");
io.initCause(exception);
throw io;
}
/**
* Verifies current version of file system
*
* @param fs file system
* @param rootdir root directory of HBase installation
* @param message if true, issues a message on System.out
*
* @throws IOException
*/
public static void checkVersion(FileSystem fs, Path rootdir, boolean message)
throws IOException {
Path versionFile = new Path(rootdir, HConstants.VERSION_FILE_NAME);
boolean versionOk = false;
if (fs.exists(versionFile)) {
FSDataInputStream s =
fs.open(new Path(rootdir, HConstants.VERSION_FILE_NAME));
String version = DataInputStream.readUTF(s);
s.close();
versionOk = version.compareTo(HConstants.FILE_SYSTEM_VERSION) == 0;
}
if (!versionOk) {
// Output on stdout so user sees it in terminal.
String msg = "File system needs to be upgraded. Run " +
"the '${HBASE_HOME}/bin/hbase migrate' script.";
if (message) {
System.out.println("WARNING! " + msg);
}
throw new FileSystemVersionException(msg);
}
}
/**
* Sets version of file system
*
* @param fs
* @param rootdir
* @throws IOException
*/
public static void setVersion(FileSystem fs, Path rootdir) throws IOException {
FSDataOutputStream s =
fs.create(new Path(rootdir, HConstants.VERSION_FILE_NAME));
s.writeUTF(HConstants.FILE_SYSTEM_VERSION);
s.close();
}
}