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opentelemetry-java-instrumentation
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More complicated logic to reflectively get VM args on different jdks 

Support the differences between IBM and Oracle jdks along with differences between 8 and 12
This commit is contained in:
Laplie Anderson 2019-08-02 10:27:45 -04:00
parent a6ba2d25fe
commit 1381e718fe
2 changed files with 112 additions and 37 deletions
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129
dd-java-agent/src/main/java/datadog/trace/agent/TracingAgent.java
View File

@ -5,17 +5,20 @@ import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.instrument.Instrumentation;
import java.lang.management.RuntimeMXBean;
import java.lang.management.ManagementFactory;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.List;
import java.util.jar.JarFile;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import sun.management.ManagementFactoryHelper;
/** Entry point for initializing the agent. */
public class TracingAgent {
@ -32,7 +35,6 @@ public class TracingAgent {
// fields must be managed under class lock
private static ClassLoader AGENT_CLASSLOADER = null;
private static ClassLoader JMXFETCH_CLASSLOADER = null;
private static URL BOOTSTRAP_URL = null;
public static void premain(final String agentArgs, final Instrumentation inst) throws Exception {
agentmain(agentArgs, inst);
@ -41,8 +43,13 @@ public class TracingAgent {
public static void agentmain(final String agentArgs, final Instrumentation inst)
throws Exception {
configureLogger();
startDatadogAgent(inst);
if (isAppUsingCustomLogManager()) {
final boolean usingCustomLogManager = isAppUsingCustomLogManager();
final URL bootstrapURL = installBootstrapJar(inst, usingCustomLogManager);
startDatadogAgent(inst, bootstrapURL);
if (usingCustomLogManager) {
System.out.println("Custom logger detected. Delaying JMXFetch initialization.");
/*
* java.util.logging.LogManager maintains a final static LogManager, which is created during class initialization.
@ -58,34 +65,38 @@ public class TracingAgent {
final Method registerCallbackMethod =
agentInstallerClass.getMethod("registerClassLoadCallback", String.class, Runnable.class);
registerCallbackMethod.invoke(
null, "java.util.logging.LogManager", new LoggingCallback(inst));
null, "java.util.logging.LogManager", new LoggingCallback(inst, bootstrapURL));
} else {
startJmxFetch(inst);
startJmxFetch(inst, bootstrapURL);
}
}
protected static class LoggingCallback implements Runnable {
private final Instrumentation inst;
private final URL bootstrapURL;
public LoggingCallback(final Instrumentation inst) {
public LoggingCallback(final Instrumentation inst, final URL bootstrapURL) {
this.inst = inst;
this.bootstrapURL = bootstrapURL;
}
@Override
public void run() {
try {
startJmxFetch(inst);
startJmxFetch(inst, bootstrapURL);
} catch (final Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
}
public static synchronized void startDatadogAgent(final Instrumentation inst) throws Exception {
installBootstrapJar(inst);
private static synchronized void startDatadogAgent(
final Instrumentation inst, final URL bootstrapURL) throws Exception {
if (AGENT_CLASSLOADER == null) {
final ClassLoader agentClassLoader =
createDatadogClassLoader("agent-tooling-and-instrumentation.jar.zip");
createDatadogClassLoader("agent-tooling-and-instrumentation.jar.zip", bootstrapURL);
final ClassLoader contextLoader = Thread.currentThread().getContextClassLoader();
try {
Thread.currentThread().setContextClassLoader(agentClassLoader);
@ -96,7 +107,8 @@ public class TracingAgent {
agentInstallerClass.getMethod("installBytebuddyAgent", Instrumentation.class);
agentInstallerMethod.invoke(null, inst);
}
{ // install global tracer
{
// install global tracer
final Class<?> tracerInstallerClass =
agentClassLoader.loadClass("datadog.trace.agent.tooling.TracerInstaller");
final Method tracerInstallerMethod =
@ -112,10 +124,11 @@ public class TracingAgent {
}
}
public static synchronized void startJmxFetch(final Instrumentation inst) throws Exception {
installBootstrapJar(inst);
private static synchronized void startJmxFetch(final Instrumentation inst, final URL bootstrapURL)
throws Exception {
if (JMXFETCH_CLASSLOADER == null) {
final ClassLoader jmxFetchClassLoader = createDatadogClassLoader("agent-jmxfetch.jar.zip");
final ClassLoader jmxFetchClassLoader =
createDatadogClassLoader("agent-jmxfetch.jar.zip", bootstrapURL);
final ClassLoader contextLoader = Thread.currentThread().getContextClassLoader();
try {
Thread.currentThread().setContextClassLoader(jmxFetchClassLoader);
@ -142,16 +155,25 @@ public class TracingAgent {
}
}
private static synchronized void installBootstrapJar(final Instrumentation inst)
private static synchronized URL installBootstrapJar(
final Instrumentation inst, final boolean usingCustomLogManager)
throws IOException, URISyntaxException {
if (BOOTSTRAP_URL == null) {
URL bootstrapURL = null;
final List<String> arguments;
// ManagementFactory loads the Logging MBean class in JDKs after 1.8
// This prevents custom logging from working correctly
// Instead, use the helper to get the bean
final RuntimeMXBean runtimeMxBean = ManagementFactoryHelper.getRuntimeMXBean();
// ManagementFactory indirectly references java.util.logging.LogManager
// - On Oracle-based JDKs after 1.8
// - On IBM-based JDKs since at least 1.7
// This prevents custom log managers from working correctly
// Use reflection to bypass the loading of the class
if (usingCustomLogManager) {
System.out.println("Custom log manager detected: getting vm args through reflection");
arguments = getVMArgumentsThroughReflection();
} else {
arguments = ManagementFactory.getRuntimeMXBean().getInputArguments();
}
for (final String arg : runtimeMxBean.getInputArguments()) {
for (final String arg : arguments) {
if (arg.startsWith("-javaagent")) {
// argument is of the form -javaagent:/path/to/dd-java-agent.jar=optionalargumentstring
final Matcher matcher = Pattern.compile("-javaagent:([^=]+).*").matcher(arg);
@ -160,14 +182,60 @@ public class TracingAgent {
throw new RuntimeException("Unable to parse javaagent parameter: " + arg);
}
BOOTSTRAP_URL = new URL("file:" + matcher.group(1));
inst.appendToBootstrapClassLoaderSearch(new JarFile(new File(BOOTSTRAP_URL.toURI())));
return;
try {
bootstrapURL = new URL("file:" + matcher.group(1));
} catch (final MalformedURLException e) {
throw new RuntimeException("Malformed javaagent parameter: " + arg);
}
}
}
if (bootstrapURL != null) {
inst.appendToBootstrapClassLoaderSearch(new JarFile(new File(bootstrapURL.toURI())));
return bootstrapURL;
} else {
throw new RuntimeException(
"Unable to install bootstrap jar. -javaagent parameter not found");
"Unable to install bootstrap jar. -javaagent parameter not parsable");
}
}
private static List<String> getVMArgumentsThroughReflection() {
try {
// Try Oracle-based
final Class managementFactoryHelperClass =
TracingAgent.class.getClassLoader().loadClass("sun.management.ManagementFactoryHelper");
final Class vmManagementClass =
TracingAgent.class.getClassLoader().loadClass("sun.management.VMManagement");
Object vmManagement;
try {
vmManagement =
managementFactoryHelperClass.getDeclaredMethod("getVMManagement").invoke(null);
} catch (final NoSuchMethodException e) {
// Older vm before getVMManagement() existed
final Field field = managementFactoryHelperClass.getDeclaredField("jvm");
field.setAccessible(true);
vmManagement = field.get(null);
field.setAccessible(false);
}
return (List<String>) vmManagementClass.getMethod("getVmArguments").invoke(vmManagement);
} catch (final ReflectiveOperationException e) {
try { // Try IBM-based.
final Class VMClass = TracingAgent.class.getClassLoader().loadClass("com.ibm.oti.vm.VM");
final String[] argArray = (String[]) VMClass.getMethod("getVMArgs").invoke(null);
return Arrays.asList(argArray);
} catch (final ReflectiveOperationException e1) {
// Fallback to default
System.out.println(
"WARNING: Unable to get VM args through reflection. A custom java.util.logging.LogManager may not work correctly");
return ManagementFactory.getRuntimeMXBean().getInputArguments();
}
}
}
@ -177,10 +245,11 @@ public class TracingAgent {
*
* @param innerJarFilename Filename of internal jar to use for the classpath of the datadog
* classloader
* @param bootStrapURL
* @return Datadog Classloader
*/
private static ClassLoader createDatadogClassLoader(final String innerJarFilename)
throws Exception {
private static ClassLoader createDatadogClassLoader(
final String innerJarFilename, final URL bootStrapURL) throws Exception {
final ClassLoader agentParent;
final String javaVersion = System.getProperty("java.version");
if (javaVersion.startsWith("1.7") || javaVersion.startsWith("1.8")) {
@ -194,7 +263,7 @@ public class TracingAgent {
ClassLoader.getSystemClassLoader().loadClass("datadog.trace.bootstrap.DatadogClassLoader");
final Constructor constructor =
loaderClass.getDeclaredConstructor(URL.class, String.class, ClassLoader.class);
return (ClassLoader) constructor.newInstance(BOOTSTRAP_URL, innerJarFilename, agentParent);
return (ClassLoader) constructor.newInstance(bootStrapURL, innerJarFilename, agentParent);
}
private static ClassLoader getPlatformClassLoader()

8
dd-java-agent/src/test/java/jvmbootstraptest/LogManagerSetter.java
View File

@ -43,6 +43,11 @@ public class LogManagerSetter {
"jmxfetch should start in premain when custom log manager found on classpath.");
}
} else if (System.getenv("JBOSS_HOME") != null) {
customAssert(
isJmxfetchStarted(),
false,
"jmxfetch startup must be delayed when JBOSS_HOME property is present.");
System.setProperty("java.util.logging.manager", CustomLogManager.class.getName());
customAssert(
LogManager.getLogManager().getClass(),
@ -50,7 +55,8 @@ public class LogManagerSetter {
.getClassLoader()
.loadClass(System.getProperty("java.util.logging.manager")),
"Javaagent should not prevent setting a custom log manager");
customAssert(
isJmxfetchStarted(), true, "jmxfetch should start after loading with JBOSS_HOME SET.");
} else {
customAssert(
isJmxfetchStarted(),