Add system property to force injection of the tracing library even though multiple javaagents have been detected (#8697)

* add system property for inject force

---------

Co-authored-by: Cecile Terpin <“[email protected]”>

Author: cecile75

dd-java-agent/src/main/java/datadog/trace/bootstrap/AgentBootstrap.java

@@ -1,5 +1,6 @@
 package datadog.trace.bootstrap;
 
+import static datadog.trace.bootstrap.SystemUtils.getPropertyOrEnvVar;
 import static java.nio.charset.StandardCharsets.UTF_8;
 
 import datadog.cli.CLIHelper;
@@ -44,8 +45,8 @@
  * </ul>
  */
 public final class AgentBootstrap {
-  static final String LIB_INJECTION_ENABLED_FLAG = "DD_INJECTION_ENABLED";
-  static final String LIB_INJECTION_FORCE_FLAG = "DD_INJECT_FORCE";
+  static final String LIB_INJECTION_ENABLED_ENV_VAR = "DD_INJECTION_ENABLED";
+  static final String LIB_INJECTION_FORCE_SYS_PROP = "dd.inject.force";
 
   private static final Class<?> thisClass = AgentBootstrap.class;
   private static final int MAX_EXCEPTION_CHAIN_LENGTH = 99;
@@ -155,11 +156,13 @@ private static void agentmainImpl(
 
   static boolean getConfig(String configName) {
     switch (configName) {
-      case LIB_INJECTION_ENABLED_FLAG:
-        return System.getenv(LIB_INJECTION_ENABLED_FLAG) != null;
-      case LIB_INJECTION_FORCE_FLAG:
-        String libInjectionForceFlag = System.getenv(LIB_INJECTION_FORCE_FLAG);
-        return "true".equalsIgnoreCase(libInjectionForceFlag) || "1".equals(libInjectionForceFlag);
+      case LIB_INJECTION_ENABLED_ENV_VAR:
+        return System.getenv(LIB_INJECTION_ENABLED_ENV_VAR) != null;
+      case LIB_INJECTION_FORCE_SYS_PROP:
+        {
+          String injectionForceFlag = getPropertyOrEnvVar(LIB_INJECTION_FORCE_SYS_PROP);
+          return "true".equalsIgnoreCase(injectionForceFlag) || "1".equals(injectionForceFlag);
+        }
       default:
         return false;
     }
@@ -285,8 +288,9 @@ static int parseJavaMajorVersion(String version) {
 
   static boolean shouldAbortDueToOtherJavaAgents() {
     // Simply considering having multiple agents
-    if (getConfig(LIB_INJECTION_ENABLED_FLAG)
-        && !getConfig(LIB_INJECTION_FORCE_FLAG)
+
+    if (getConfig(LIB_INJECTION_ENABLED_ENV_VAR)
+        && !getConfig(LIB_INJECTION_FORCE_SYS_PROP)
         && getAgentFilesFromVMArguments().size() > 1) {
       // Formatting agent file list, Java 7 style
       StringBuilder agentFiles = new StringBuilder();
@@ -305,7 +309,7 @@ && getAgentFilesFromVMArguments().size() > 1) {
           "Info: multiple JVM agents detected, found "
               + agentFiles
               + ". Loading multiple APM/Tracing agent is not a recommended or supported configuration."
-              + "Please set the DD_INJECT_FORCE configuration to TRUE to load Datadog APM/Tracing agent.");
+              + "Please set the environment variable DD_INJECT_FORCE or the system property dd.inject.force to TRUE to load Datadog APM/Tracing agent.");
       return true;
     }
     return false;

dd-java-agent/src/main/java/datadog/trace/bootstrap/SystemUtils.java

@@ -30,4 +30,16 @@ public static String getPropertyOrDefault(String property, String defaultValue)
       return defaultValue;
     }
   }
+
+  private static String toEnvVar(String string) {
+    return string.replace('.', '_').replace('-', '_').toUpperCase();
+  }
+
+  public static String getPropertyOrEnvVar(String property) {
+    String envVarValue = System.getenv(toEnvVar(property));
+    if (envVarValue != null) {
+      return envVarValue;
+    }
+    return System.getProperty(property);
+  }
 }