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jeanbisuttitrask
jeanbisutti
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trask
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Fix "Class path contains multiple SLF4J bindings" during runtime atta… (#380)
* Fix "Class path contains multiple SLF4J bindings" during runtime attachment * Update runtime-attach/build.gradle.kts Co-authored-by: Trask Stalnaker <[email protected]> * Renaming Co-authored-by: Trask Stalnaker <[email protected]>
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‎runtime-attach-core/README.md‎

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# Runtime attachment core
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This project is dedicated to providers of the [OpenTelemetry Java agent](https://github.com/open-telemetry/opentelemetry-java-instrumentation). It helps them to build a dependency to runtime attach their agent jar file.
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You can find [here](../runtime-attach/README.md) the project of the distribution published by OpenTelemetry.

‎runtime-attach-core/build.gradle.kts‎

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plugins {
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id("otel.java-conventions")
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id("otel.publish-conventions")
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}
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description = "To help in create an OpenTelemetry distro able to runtime attach an OpenTelemetry Java Instrumentation agent"
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dependencies {
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implementation("net.bytebuddy:byte-buddy-agent:1.11.18")
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// Used by byte-buddy but not brought in as a transitive dependency.
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compileOnly("com.google.code.findbugs:annotations")
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}

runtime-attach/src/main/java/io/opentelemetry/contrib/attach/AgentFileProvider.java renamed to runtime-attach-core/src/main/java/io/opentelemetry/contrib/attach/AgentFileProvider.java

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@@ -5,24 +5,25 @@
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package io.opentelemetry.contrib.attach;
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import io.opentelemetry.javaagent.OpenTelemetryAgent;
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import java.io.File;
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import java.io.IOException;
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import java.io.InputStream;
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import java.net.URL;
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import java.nio.file.Files;
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import java.nio.file.Path;
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import java.security.CodeSource;
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final class AgentFileProvider {
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19-
static File getAgentFile() {
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private final String agentJarResourceName;
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verifyExistenceOfAgentJarFile();
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AgentFileProvider(String agentJarResourceName) {
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this.agentJarResourceName = agentJarResourceName;
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}
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File getAgentFile() {
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Path tempDirPath = createTempDir();
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Path tempAgentJarPath = createTempAgentJarFile(tempDirPath);
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Path tempAgentJarPath = createTempAgentJarFileIn(tempDirPath);
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deleteTempDirOnJvmExit(tempDirPath, tempAgentJarPath);
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@@ -34,13 +35,6 @@ private static void deleteTempDirOnJvmExit(Path tempDirPath, Path tempAgentJarPa
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tempDirPath.toFile().deleteOnExit();
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}
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private static void verifyExistenceOfAgentJarFile() {
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CodeSource codeSource = OpenTelemetryAgent.class.getProtectionDomain().getCodeSource();
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if (codeSource == null) {
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throw new IllegalStateException("could not get agent jar location");
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}
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}
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private static Path createTempDir() {
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Path tempDir;
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try {
@@ -51,23 +45,18 @@ private static Path createTempDir() {
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return tempDir;
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}
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private static Path createTempAgentJarFile(Path tempDir) {
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URL url = OpenTelemetryAgent.class.getProtectionDomain().getCodeSource().getLocation();
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try {
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return copyTo(url, tempDir, "agent.jar");
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private Path createTempAgentJarFileIn(Path tempDir) {
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Path agentJarPath = tempDir.resolve("agent.jar");
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try (InputStream jarAsInputStream =
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AgentFileProvider.class.getResourceAsStream(this.agentJarResourceName)) {
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if (jarAsInputStream == null) {
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throw new IllegalStateException(this.agentJarResourceName + " resource can't be found");
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}
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Files.copy(jarAsInputStream, agentJarPath);
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} catch (IOException e) {
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throw new IllegalStateException(
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"Runtime attachment can't create agent jar file in temp directory", e);
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}
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return agentJarPath;
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}
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private static Path copyTo(URL url, Path tempDir, String fileName) throws IOException {
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Path tempFile = tempDir.resolve(fileName);
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try (InputStream in = url.openStream()) {
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Files.copy(in, tempFile);
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}
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return tempFile;
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}
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private AgentFileProvider() {}
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}

‎runtime-attach-core/src/main/java/io/opentelemetry/contrib/attach/CoreRuntimeAttach.java‎

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/*
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* Copyright The OpenTelemetry Authors
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* SPDX-License-Identifier: Apache-2.0
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*/
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package io.opentelemetry.contrib.attach;
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import java.io.File;
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import java.lang.management.ManagementFactory;
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import net.bytebuddy.agent.ByteBuddyAgent;
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/** This class allows you to attach the OpenTelemetry Java agent at runtime. */
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public final class CoreRuntimeAttach {
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private static final String AGENT_ENABLED_PROPERTY = "otel.javaagent.enabled";
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private static final String AGENT_ENABLED_ENV_VAR = "OTEL_JAVAAGENT_ENABLED";
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static final String MAIN_METHOD_CHECK_PROP =
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"otel.javaagent.testing.runtime-attach.main-method-check";
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private final String agentJarResourceName;
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/**
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* Creates a new {@code DistroRuntimeAttach} from the resource name of the agent jar.
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*
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* @param agentJarResourceName Resource name of the agent jar.
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*/
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public CoreRuntimeAttach(String agentJarResourceName) {
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this.agentJarResourceName = agentJarResourceName;
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}
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/**
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* Attach the OpenTelemetry Java agent to the current JVM. The attachment must be requested at the
33+
* beginning of the main method.
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*/
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public void attachJavaagentToCurrentJVM() {
36+
if (!shouldAttach()) {
37+
return;
38+
}
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40+
AgentFileProvider agentFileProvider = new AgentFileProvider(agentJarResourceName);
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File javaagentFile = agentFileProvider.getAgentFile();
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ByteBuddyAgent.attach(javaagentFile, getPid());
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45+
if (!agentIsAttached()) {
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printError("Agent was not attached. An unexpected issue has happened.");
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}
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}
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50+
@SuppressWarnings("SystemOut")
51+
private static void printError(String message) {
52+
// not using java.util.logging in order to avoid initializing the global LogManager
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// too early (and incompatibly with the user's app),
54+
// and because this is too early to use the Javaagent's PatchLogger
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System.err.println(message);
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}
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58+
private static boolean shouldAttach() {
59+
if (agentIsDisabledWithProp()) {
60+
return false;
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}
62+
if (agentIsDisabledWithEnvVar()) {
63+
return false;
64+
}
65+
if (agentIsAttached()) {
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return false;
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}
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if (mainMethodCheckIsEnabled() && !isMainThread()) {
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printError(
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"Agent is not attached because runtime attachment was not requested from main thread.");
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return false;
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}
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if (mainMethodCheckIsEnabled() && !isMainMethod()) {
74+
printError(
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"Agent is not attached because runtime attachment was not requested from main method.");
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return false;
77+
}
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return true;
79+
}
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81+
private static boolean agentIsDisabledWithProp() {
82+
String agentEnabledPropValue = System.getProperty(AGENT_ENABLED_PROPERTY);
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return "false".equalsIgnoreCase(agentEnabledPropValue);
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}
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86+
private static boolean agentIsDisabledWithEnvVar() {
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String agentEnabledEnvVarValue = System.getenv(AGENT_ENABLED_ENV_VAR);
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return "false".equals(agentEnabledEnvVarValue);
89+
}
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91+
private static boolean agentIsAttached() {
92+
try {
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Class.forName("io.opentelemetry.javaagent.OpenTelemetryAgent", false, null);
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return true;
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} catch (ClassNotFoundException e) {
96+
return false;
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}
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}
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private static boolean mainMethodCheckIsEnabled() {
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String mainThreadCheck = System.getProperty(MAIN_METHOD_CHECK_PROP);
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return !"false".equals(mainThreadCheck);
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}
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private static boolean isMainThread() {
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Thread currentThread = Thread.currentThread();
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return "main".equals(currentThread.getName());
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}
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static boolean isMainMethod() {
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StackTraceElement bottomOfStack = findBottomOfStack(Thread.currentThread());
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String methodName = bottomOfStack.getMethodName();
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return "main".equals(methodName);
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}
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private static StackTraceElement findBottomOfStack(Thread thread) {
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StackTraceElement[] stackTrace = thread.getStackTrace();
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return stackTrace[stackTrace.length - 1];
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}
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private static String getPid() {
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return ManagementFactory.getRuntimeMXBean().getName().split("@")[0];
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}
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}

‎runtime-attach/build.gradle.kts‎

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@@ -3,11 +3,13 @@ plugins {
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id("otel.publish-conventions")
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}
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6-
description = "Utility to attach OpenTelemetry Java Instrumentation agent from classpath"
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description = "To runtime attach the OpenTelemetry Java Instrumentation agent"
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val agent: Configuration by configurations.creating
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810
dependencies {
9-
compileOnly("io.opentelemetry.javaagent:opentelemetry-javaagent:1.6.0")
10-
implementation("net.bytebuddy:byte-buddy-agent:1.11.18")
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implementation(project(":runtime-attach-core"))
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agent("io.opentelemetry.javaagent:opentelemetry-javaagent:1.15.0")
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1214
// Used by byte-buddy but not brought in as a transitive dependency.
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compileOnly("com.google.code.findbugs:annotations")
@@ -23,3 +25,13 @@ tasks.test {
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useJUnitPlatform()
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setForkEvery(1) // One JVM by test class to avoid a test class launching a runtime attachment influences the behavior of another test class
2527
}
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tasks {
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jar {
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inputs.files(agent)
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from({
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agent.singleFile
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})
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rename { "otel-agent.jar" }
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}
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}

‎runtime-attach/src/main/java/io/opentelemetry/contrib/attach/RuntimeAttach.java‎

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package io.opentelemetry.contrib.attach;
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import java.io.File;
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import java.lang.management.ManagementFactory;
10-
import net.bytebuddy.agent.ByteBuddyAgent;
11-
128
/** This class allows you to attach the OpenTelemetry Java agent at runtime. */
139
public final class RuntimeAttach {
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15-
private static final String AGENT_ENABLED_PROPERTY = "otel.javaagent.enabled";
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private static final String AGENT_ENABLED_ENV_VAR = "OTEL_JAVAAGENT_ENABLED";
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static final String MAIN_METHOD_CHECK_PROP =
18-
"otel.javaagent.testing.runtime-attach.main-method-check";
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2011
/**
2112
* Attach the OpenTelemetry Java agent to the current JVM. The attachment must be requested at the
2213
* beginning of the main method.
2314
*/
2415
public static void attachJavaagentToCurrentJVM() {
25-
if (!shouldAttach()) {
26-
return;
27-
}
28-
29-
File javaagentFile = AgentFileProvider.getAgentFile();
30-
ByteBuddyAgent.attach(javaagentFile, getPid());
31-
32-
if (!agentIsAttached()) {
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printError("Agent was not attached. An unexpected issue has happened.");
34-
}
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}
36-
37-
@SuppressWarnings("SystemOut")
38-
private static void printError(String message) {
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// not using java.util.logging in order to avoid initializing the global LogManager
40-
// too early (and incompatibly with the user's app),
41-
// and because this is too early to use the Javaagent's PatchLogger
42-
System.err.println(message);
43-
}
44-
45-
private static boolean shouldAttach() {
46-
if (agentIsDisabledWithProp()) {
47-
return false;
48-
}
49-
if (agentIsDisabledWithEnvVar()) {
50-
return false;
51-
}
52-
if (agentIsAttached()) {
53-
return false;
54-
}
55-
if (mainMethodCheckIsEnabled() && !isMainThread()) {
56-
printError(
57-
"Agent is not attached because runtime attachment was not requested from main thread.");
58-
return false;
59-
}
60-
if (mainMethodCheckIsEnabled() && !isMainMethod()) {
61-
printError(
62-
"Agent is not attached because runtime attachment was not requested from main method.");
63-
return false;
64-
}
65-
return true;
66-
}
67-
68-
private static boolean agentIsDisabledWithProp() {
69-
String agentEnabledPropValue = System.getProperty(AGENT_ENABLED_PROPERTY);
70-
return "false".equalsIgnoreCase(agentEnabledPropValue);
71-
}
7216

73-
private static boolean agentIsDisabledWithEnvVar() {
74-
String agentEnabledEnvVarValue = System.getenv(AGENT_ENABLED_ENV_VAR);
75-
return "false".equals(agentEnabledEnvVarValue);
76-
}
77-
78-
private static boolean agentIsAttached() {
79-
try {
80-
Class.forName("io.opentelemetry.javaagent.OpenTelemetryAgent", false, null);
81-
return true;
82-
} catch (ClassNotFoundException e) {
83-
return false;
84-
}
85-
}
86-
87-
private static boolean mainMethodCheckIsEnabled() {
88-
String mainThreadCheck = System.getProperty(MAIN_METHOD_CHECK_PROP);
89-
return !"false".equals(mainThreadCheck);
90-
}
91-
92-
private static boolean isMainThread() {
93-
Thread currentThread = Thread.currentThread();
94-
return "main".equals(currentThread.getName());
95-
}
96-
97-
static boolean isMainMethod() {
98-
StackTraceElement bottomOfStack = findBottomOfStack(Thread.currentThread());
99-
String methodName = bottomOfStack.getMethodName();
100-
return "main".equals(methodName);
101-
}
102-
103-
private static StackTraceElement findBottomOfStack(Thread thread) {
104-
StackTraceElement[] stackTrace = thread.getStackTrace();
105-
return stackTrace[stackTrace.length - 1];
106-
}
17+
CoreRuntimeAttach distroRuntimeAttach = new CoreRuntimeAttach("/otel-agent.jar");
10718

108-
private static String getPid() {
109-
return ManagementFactory.getRuntimeMXBean().getName().split("@")[0];
19+
distroRuntimeAttach.attachJavaagentToCurrentJVM();
11020
}
11121

11222
private RuntimeAttach() {}

‎runtime-attach/src/test/java/io/opentelemetry/contrib/attach/AbstractAttachmentTest.java‎

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1313
@BeforeAll
1414
static void disableMainThreadCheck() {
15-
System.setProperty(RuntimeAttach.MAIN_METHOD_CHECK_PROP, "false");
15+
System.setProperty(CoreRuntimeAttach.MAIN_METHOD_CHECK_PROP, "false");
1616
}
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1818
boolean isAttached() {

‎settings.gradle.kts‎

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@@ -47,6 +47,7 @@ include(":micrometer-meter-provider")
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include(":jmx-metrics")
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include(":maven-extension")
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include(":runtime-attach")
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include(":runtime-attach-core")
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include(":samplers")
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include(":static-instrumenter:agent-instrumenter")
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include(":static-instrumenter:gradle-plugin")

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