co.elastic.apm.attach.ElasticApmAttacher Maven / Gradle / Ivy
/*-
* #%L
* Elastic APM Java agent
* %%
* Copyright (C) 2018 - 2020 Elastic and contributors
* %%
* Licensed to Elasticsearch B.V. under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch B.V. 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.
* #L%
*/
package co.elastic.apm.attach;
import net.bytebuddy.agent.ByteBuddyAgent;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;
import java.security.DigestInputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
/**
* Attaches the Elastic Apm agent to the current or a remote JVM
*/
public class ElasticApmAttacher {
/**
* This key is very short on purpose.
* The longer the agent argument ({@code -javaagent:=}), the greater the chance that the max length of the agent argument is reached.
* Because of a bug in the {@linkplain ByteBuddyAgent.AttachmentProvider.ForEmulatedAttachment emulated attachment},
* this can even lead to segfaults.
*/
private static final String TEMP_PROPERTIES_FILE_KEY = "c";
/**
* Attaches the Elastic Apm agent to the current JVM.
*
* This method may only be invoked once.
*
*
* Tries to load {@code elasticapm.properties} from the classpath, if exists.
*
*
* @throws IllegalStateException if there was a problem while attaching the agent to this VM
*/
public static void attach() {
attach(loadProperties("elasticapm.properties"));
}
/**
* Attaches the Elastic Apm agent to the current JVM.
*
* This method may only be invoked once.
*
*
* @param propertiesLocation the location within the classpath which contains the agent configuration properties file
* @throws IllegalStateException if there was a problem while attaching the agent to this VM
* @since 1.11.0
*/
public static void attach(String propertiesLocation) {
attach(loadProperties(propertiesLocation));
}
private static Map loadProperties(String propertiesLocation) {
Map propertyMap = new HashMap<>();
final Properties props = new Properties();
try (InputStream resourceStream = ElasticApmAttacher.class.getClassLoader().getResourceAsStream(propertiesLocation)) {
if (resourceStream != null) {
props.load(resourceStream);
for (String propertyName : props.stringPropertyNames()) {
propertyMap.put(propertyName, props.getProperty(propertyName));
}
}
} catch (IOException e) {
e.printStackTrace();
}
return propertyMap;
}
/**
* Attaches the Elastic Apm agent to the current JVM.
*
* This method may only be invoked once.
*
*
* @param configuration the agent configuration
* @throws IllegalStateException if there was a problem while attaching the agent to this VM
*/
public static void attach(Map configuration) {
// optimization, this is checked in AgentMain#init again
if (Boolean.getBoolean("ElasticApm.attached")) {
return;
}
attach(ByteBuddyAgent.ProcessProvider.ForCurrentVm.INSTANCE.resolve(), configuration);
}
static File createTempProperties(Map configuration) {
File tempFile = null;
if (!configuration.isEmpty()) {
Properties properties = new Properties();
properties.putAll(configuration);
// when an external configuration file is used, we have to load it last to give it higher priority
String externalConfig = configuration.get("config_file");
if (null != externalConfig) {
try (FileInputStream stream = new FileInputStream(externalConfig)) {
properties.load(stream);
} catch (IOException e) {
e.printStackTrace();
}
}
try {
tempFile = File.createTempFile("elstcapm", ".tmp");
try (FileOutputStream outputStream = new FileOutputStream(tempFile)) {
properties.store(outputStream, null);
}
} catch (IOException e) {
e.printStackTrace();
}
}
return tempFile;
}
/**
* Attaches the agent to a remote JVM
*
* @param pid the PID of the JVM the agent should be attached on
* @param configuration the agent configuration
*/
public static void attach(String pid, Map configuration) {
attach(pid, configuration, AgentJarFileHolder.INSTANCE.agentJarFile);
}
/**
* Attaches the agent to a remote JVM
*
* @param pid the PID of the JVM the agent should be attached on
* @param configuration the agent configuration
* @param agentJarFile
*/
public static void attach(String pid, Map configuration, File agentJarFile) {
File tempFile = createTempProperties(configuration);
String agentArgs = tempFile == null ? null : TEMP_PROPERTIES_FILE_KEY + "=" + tempFile.getAbsolutePath();
ByteBuddyAgent.attach(agentJarFile, pid, agentArgs, ElasticAttachmentProvider.get());
if (tempFile != null) {
if (!tempFile.delete()) {
tempFile.deleteOnExit();
}
}
}
/**
* Attaches the agent to a remote JVM
*
* @param pid the PID of the JVM the agent should be attached on
* @param agentArgs the agent arguments
* @deprecated use {@link #attach(String, Map)}
*/
@Deprecated
public static void attach(String pid, String agentArgs) {
ByteBuddyAgent.attach(AgentJarFileHolder.INSTANCE.agentJarFile, pid, agentArgs, ElasticAttachmentProvider.get());
}
public static File getBundledAgentJarFile() {
return AgentJarFileHolder.INSTANCE.agentJarFile;
}
private enum AgentJarFileHolder {
INSTANCE;
// initializes lazily and ensures it's only loaded once
final File agentJarFile = getAgentJarFile();
/**
* {@see co.elastic.apm.agent.util.IOUtils#exportResourceToTemp(java.lang.String, java.lang.String, java.lang.String)} who share the same code.
*/
private static File getAgentJarFile() {
try (InputStream agentJar = ElasticApmAttacher.class.getResourceAsStream("/elastic-apm-agent.jar")) {
if (agentJar == null) {
return null;
}
String hash = md5Hash(ElasticApmAttacher.class.getResourceAsStream("/elastic-apm-agent.jar"));
// we have to include current user name as multiple copies of the same agent could be attached
// to multiple JVMs, each running under a different user. Also, we have to make it path-friendly.
String user = md5Hash(System.getProperty("user.name"));
File tempAgentJar = new File(System.getProperty("java.io.tmpdir"), String.format("elastic-apm-agent-%s-%s.jar", user, hash));
if (!tempAgentJar.exists()) {
try (FileOutputStream out = new FileOutputStream(tempAgentJar)) {
FileChannel channel = out.getChannel();
// If multiple JVM start on same compute, they can write in same file
// and this file will be corrupted.
try (FileLock ignored = channel.lock()) {
if (tempAgentJar.length() == 0) {
byte[] buffer = new byte[1024];
for (int length; (length = agentJar.read(buffer)) != -1; ) {
out.write(buffer, 0, length);
}
}
}
}
} else if (!md5Hash(new FileInputStream(tempAgentJar)).equals(hash)) {
throw new IllegalStateException("Invalid MD5 checksum of " + tempAgentJar + ". Please delete this file.");
}
return tempAgentJar;
} catch (NoSuchAlgorithmException | IOException e) {
throw new IllegalStateException(e);
}
}
}
static String md5Hash(InputStream resourceAsStream) throws IOException, NoSuchAlgorithmException {
try (InputStream agentJar = resourceAsStream) {
MessageDigest md = MessageDigest.getInstance("MD5");
byte[] buffer = new byte[1024];
DigestInputStream dis = new DigestInputStream(agentJar, md);
while (dis.read(buffer) != -1) {
}
return String.format("%032x", new BigInteger(1, md.digest()));
}
}
static String md5Hash(String s) throws NoSuchAlgorithmException {
MessageDigest md = MessageDigest.getInstance("MD5");
md.update(s.getBytes());
return String.format("%032x", new BigInteger(1, md.digest()));
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy