support dynamic attach

Author: zeitlinger

javaagent-bootstrap/src/main/java/io/opentelemetry/javaagent/OpenTelemetryAgent.java

@@ -5,6 +5,7 @@
 
 package io.opentelemetry.javaagent;
 
+import io.opentelemetry.javaagent.bootstrap.AgentArgUtil;
 import io.opentelemetry.javaagent.bootstrap.AgentInitializer;
 import io.opentelemetry.javaagent.bootstrap.InstrumentationHolder;
 import io.opentelemetry.javaagent.bootstrap.JavaagentFileHolder;
@@ -15,6 +16,7 @@
 import java.net.URL;
 import java.util.jar.JarFile;
 import java.util.jar.Manifest;
+import javax.annotation.Nullable;
 
 /**
  * Premain-Class for the OpenTelemetry Java agent.
@@ -42,15 +44,17 @@
 public final class OpenTelemetryAgent {
 
   public static void premain(String agentArgs, Instrumentation inst) {
-    startAgent(inst, true);
+    startAgent(inst, agentArgs, true);
   }
 
   public static void agentmain(String agentArgs, Instrumentation inst) {
-    startAgent(inst, false);
+    startAgent(inst, agentArgs, false);
   }
 
-  private static void startAgent(Instrumentation inst, boolean fromPremain) {
+  private static void startAgent(
+      Instrumentation inst, @Nullable String agentArgs, boolean fromPremain) {
     try {
+      AgentArgUtil.setSystemProperties(agentArgs);
       File javaagentFile = installBootstrapJar(inst);
       InstrumentationHolder.setInstrumentation(inst);
       JavaagentFileHolder.setJavaagentFile(javaagentFile);

javaagent-bootstrap/src/main/java/io/opentelemetry/javaagent/bootstrap/AgentArgUtil.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.bootstrap;
+
+import javax.annotation.Nullable;
+
+public class AgentArgUtil {
+
+  private AgentArgUtil() {}
+
+  @SuppressWarnings("SystemOut")
+  public static void setSystemProperties(@Nullable String agentArgs) {
+    boolean debug = false;
+    if (agentArgs != null && !agentArgs.isEmpty()) {
+      String[] options = agentArgs.split(";");
+      for (String option : options) {
+        String[] keyValue = option.split("=");
+        if (keyValue.length == 2) {
+          if (keyValue[0].equals("otel.javaagent.debug")) {
+            debug = Boolean.parseBoolean(keyValue[1]);
+          } else {
+            System.setProperty(keyValue[0], keyValue[1]);
+            if (debug) {
+              System.out.println("Setting property [" + keyValue[0] + "] = " + keyValue[1]);
+            }
+          }
+        }
+      }
+    }
+  }
+}

smoke-tests/src/test/java/io/opentelemetry/smoketest/AbstractTestContainerManager.java

@@ -27,6 +27,8 @@ protected Map<String, String> getAgentEnvironment(
         jvmArgsEnvVarName,
         "-Xmx512m -javaagent:/"
             + TARGET_AGENT_FILENAME
+            // args passed to the agent directly
+            + "=otel.javaagent.debug=true;otel.bsp.schedule.delay=10ms"
             // Liberty20Jdk11, Payara6Jdk11 and Payara6Jdk17 fail with
             // java.util.zip.ZipException: Invalid CEN header (invalid zip64 extra data field size)
             + " -Djdk.util.zip.disableZip64ExtraFieldValidation=true");
@@ -36,13 +38,11 @@ protected Map<String, String> getAgentEnvironment(
     environment.put("OTEL_EXPORTER_OTLP_PROTOCOL", "grpc");
 
     environment.put("OTEL_BSP_MAX_EXPORT_BATCH_SIZE", "1");
-    environment.put("OTEL_BSP_SCHEDULE_DELAY", "10ms");
     environment.put("OTEL_METRIC_EXPORT_INTERVAL", "1000");
     environment.put("OTEL_EXPORTER_OTLP_ENDPOINT", "http://" + BACKEND_ALIAS + ":8080");
     if (setServiceName) {
       environment.put("OTEL_RESOURCE_ATTRIBUTES", "service.name=smoke-test");
     }
-    environment.put("OTEL_JAVAAGENT_DEBUG", "true");
     environment.put("OTEL_EXPERIMENTAL_JAVASCRIPT_SNIPPET", "<script>console.log(hi)</script>");
     environment.put("OTEL_INSTRUMENTATION_RUNTIME_TELEMETRY_PACKAGE_EMITTER_ENABLED", "true");
     return environment;