/**
* Copyright 2011 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.monitoring;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.nio.channels.FileChannel;
import java.util.Enumeration;
import java.util.Set;
import org.apache.hadoop.io.IOUtils;
import org.apache.log4j.Appender;
import org.apache.log4j.FileAppender;
import org.apache.log4j.Logger;
import com.google.common.collect.Sets;
/**
* Utility functions for reading the log4j logs that are
* being written by HBase.
*/
public abstract class LogMonitoring {
public static Set<File> getActiveLogFiles() throws IOException {
Set<File> ret = Sets.newHashSet();
Appender a;
@SuppressWarnings("unchecked")
Enumeration<Appender> e = Logger.getRootLogger().getAllAppenders();
while (e.hasMoreElements()) {
a = e.nextElement();
if (a instanceof FileAppender) {
FileAppender fa = (FileAppender) a;
String filename = fa.getFile();
ret.add(new File(filename));
}
}
return ret;
}
public static void dumpTailOfLogs(
PrintWriter out, long tailKb) throws IOException {
Set<File> logs = LogMonitoring.getActiveLogFiles();
for (File f : logs) {
out.println("+++++++++++++++++++++++++++++++");
out.println(f.getAbsolutePath());
out.println("+++++++++++++++++++++++++++++++");
try {
dumpTailOfLog(f, out, tailKb);
} catch (IOException ioe) {
out.println("Unable to dump log at " + f);
ioe.printStackTrace(out);
}
out.println("\n\n");
}
}
private static void dumpTailOfLog(File f, PrintWriter out, long tailKb)
throws IOException {
FileInputStream fis = new FileInputStream(f);
try {
FileChannel channel = fis.getChannel();
channel.position(Math.max(0, channel.size() - tailKb*1024));
BufferedReader r = new BufferedReader(
new InputStreamReader(fis));
r.readLine(); // skip the first partial line
String line;
while ((line = r.readLine()) != null) {
out.println(line);
}
} finally {
IOUtils.closeStream(fis);
}
}
}