TraceConfigInstrumentation implements Instrumenter directly

dd-java-agent/agent-tooling/src/main/java/datadog/trace/agent/tooling/Instrumenter.java

@@ -105,11 +105,11 @@ public interface Instrumenter {
       return getConfigEnabled("dd.integrations.enabled", true);
     }
 
-    protected static String getPropOrEnv(final String name) {
+    public static String getPropOrEnv(final String name) {
       return System.getProperty(name, System.getenv(propToEnvName(name)));
     }
 
-    private static String propToEnvName(final String name) {
+    public static String propToEnvName(final String name) {
       return name.toUpperCase().replace(".", "_");
     }
   }

dd-java-agent/instrumentation/trace-annotation/src/main/java/datadog/trace/instrumentation/trace_annotation/TraceConfigInstrumentation.java

@@ -17,9 +17,18 @@ import net.bytebuddy.description.method.MethodDescription;
 import net.bytebuddy.description.type.TypeDescription;
 import net.bytebuddy.matcher.ElementMatcher;
 
+/**
+ * TraceConfig Instrumentation does not extend Default.
+ *
+ * <p>Instead it directly implements Instrumenter#instrument() and adds one default Instrumenter for
+ * every configured class+method-list.
+ *
+ * <p>If this becomes a more common use case the building logic should be abstracted out into a
+ * super class.
+ */
 @Slf4j
 @AutoService(Instrumenter.class)
-public class TraceConfigInstrumentation extends Instrumenter.Default {
+public class TraceConfigInstrumentation implements Instrumenter {
   private static final String CONFIG_NAME = "dd.trace.methods";
 
   static final String PACKAGE_CLASS_NAME_REGEX = "[\\w.\\$]+";
@@ -38,9 +47,7 @@ public class TraceConfigInstrumentation extends Instrumenter.Default {
   private final Map<String, Set<String>> classMethodsToTrace;
 
   public TraceConfigInstrumentation() {
-    super("trace", "trace-config");
+    final String configString = Default.getPropOrEnv(CONFIG_NAME);
-
-    final String configString = getPropOrEnv(CONFIG_NAME);
     if (configString == null || configString.trim().isEmpty()) {
       classMethodsToTrace = Collections.emptyMap();
 
@@ -130,6 +137,16 @@ public class TraceConfigInstrumentation extends Instrumenter.Default {
     throw new RuntimeException("TracerConfigInstrumentation must not use TypeMatcher");
   }
 
+  @Override
+  public ElementMatcher<? super ClassLoader> classLoaderMatcher() {
+    throw new RuntimeException("TracerConfigInstrumentation must not use classLoaderMatcher");
+  }
+
+  @Override
+  public String[] helperClassNames() {
+    throw new RuntimeException("TracerConfigInstrumentation must not use helperClassNames");
+  }
+
   @Override
   public Map<ElementMatcher, String> transformers() {
     throw new RuntimeException("TracerConfigInstrumentation must not use transformers.");