/*
* 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.cassandra.utils;
import java.io.*;
import java.lang.management.ManagementFactory;
import java.lang.management.RuntimeMXBean;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.List;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.text.StrBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Utility to generate heap dumps.
*
*/
public final class HeapUtils
{
private static final Logger logger = LoggerFactory.getLogger(HeapUtils.class);
/**
* Generates a HEAP dump in the directory specified by the <code>HeapDumpPath</code> JVM option
* or in the <code>CASSANDRA_HOME</code> directory.
*/
public static void generateHeapDump()
{
Long processId = getProcessId();
if (processId == null)
{
logger.error("The process ID could not be retrieved. Skipping heap dump generation.");
return;
}
String heapDumpPath = getHeapDumpPathOption();
if (heapDumpPath == null)
{
String cassandraHome = System.getenv("CASSANDRA_HOME");
if (cassandraHome == null)
{
return;
}
heapDumpPath = cassandraHome;
}
Path dumpPath = FileSystems.getDefault().getPath(heapDumpPath);
if (Files.isDirectory(dumpPath))
{
dumpPath = dumpPath.resolve("java_pid" + processId + ".hprof");
}
String jmapPath = getJmapPath();
// The jmap file could not be found. In this case let's default to jmap in the hope that it is in the path.
String jmapCommand = jmapPath == null ? "jmap" : jmapPath;
String[] dumpCommands = new String[] {jmapCommand,
"-dump:format=b,file=" + dumpPath,
processId.toString()};
// Lets also log the Heap histogram
String[] histoCommands = new String[] {jmapCommand,
"-histo",
processId.toString()};
try
{
logProcessOutput(Runtime.getRuntime().exec(dumpCommands));
logProcessOutput(Runtime.getRuntime().exec(histoCommands));
}
catch (IOException e)
{
logger.error("The heap dump could not be generated due to the following error: ", e);
}
}
/**
* Retrieve the path to the JMAP executable.
* @return the path to the JMAP executable or null if it cannot be found.
*/
private static String getJmapPath()
{
// Searching in the JAVA_HOME is safer than searching into System.getProperty("java.home") as the Oracle
// JVM might use the JRE which do not contains jmap.
String javaHome = System.getenv("JAVA_HOME");
if (javaHome == null)
return null;
File javaBinDirectory = new File(javaHome, "bin");
File[] files = javaBinDirectory.listFiles(new FilenameFilter()
{
public boolean accept(File dir, String name)
{
return name.startsWith("jmap");
}
});
return ArrayUtils.isEmpty(files) ? null : files[0].getPath();
}
/**
* Logs the output of the specified process.
*
* @param p the process
* @throws IOException if an I/O problem occurs
*/
private static void logProcessOutput(Process p) throws IOException
{
BufferedReader input = new BufferedReader(new InputStreamReader(p.getInputStream()));
StrBuilder builder = new StrBuilder();
String line;
while ((line = input.readLine()) != null)
{
builder.appendln(line);
}
logger.info(builder.toString());
}
/**
* Retrieves the value of the <code>HeapDumpPath</code> JVM option.
* @return the value of the <code>HeapDumpPath</code> JVM option or <code>null</code> if the value has not been
* specified.
*/
private static String getHeapDumpPathOption()
{
RuntimeMXBean runtimeMxBean = ManagementFactory.getRuntimeMXBean();
List<String> inputArguments = runtimeMxBean.getInputArguments();
String heapDumpPathOption = null;
for (String argument : inputArguments)
{
if (argument.startsWith("-XX:HeapDumpPath="))
{
heapDumpPathOption = argument;
// We do not break in case the option has been specified several times.
// In general it seems that JVMs use the right-most argument as the winner.
}
}
if (heapDumpPathOption == null)
return null;
return heapDumpPathOption.substring(17, heapDumpPathOption.length());
}
/**
* Retrieves the process ID or <code>null</code> if the process ID cannot be retrieved.
* @return the process ID or <code>null</code> if the process ID cannot be retrieved.
*/
private static Long getProcessId()
{
// Once Java 9 is ready the process API should provide a better way to get the process ID.
long pid = SigarLibrary.instance.getPid();
if (pid >= 0)
return Long.valueOf(pid);
return getProcessIdFromJvmName();
}
/**
* Retrieves the process ID from the JVM name.
* @return the process ID or <code>null</code> if the process ID cannot be retrieved.
*/
private static Long getProcessIdFromJvmName()
{
// the JVM name in Oracle JVMs is: '<pid>@<hostname>' but this might not be the case on all JVMs
String jvmName = ManagementFactory.getRuntimeMXBean().getName();
try
{
return Long.parseLong(jvmName.split("@")[0]);
}
catch (NumberFormatException e)
{
// ignore
}
return null;
}
/**
* The class must not be instantiated.
*/
private HeapUtils()
{
}
}