fix build

Author: amarziali

dd-java-agent/instrumentation/jetty-client-9.1/build.gradle

@@ -52,20 +52,26 @@ addTestSuiteForDir('latestDepTest', 'jetty10')
   it.javaLauncher = getJavaLauncherFor(11)
 }
 
-configurations{
+configurations {
   all {
     resolutionStrategy {
       force "org.slf4j:slf4j-api:${versions.slf4j}"
     }
   }
+  testRuntimeClasspath {
+    resolutionStrategy {
+      force group: 'org.eclipse.jetty', name: 'jetty-client', version: '9.1.0.v20131115'
+      force group: 'org.eclipse.jetty', name: 'jetty-util', version: '9.1.0.v20131115'
+      force group: 'org.eclipse.jetty', name: 'jetty-io', version: '9.1.0.v20131115'
+    }
+  }
 }
 
 dependencies {
   compileOnly group: 'org.eclipse.jetty', name: 'jetty-client', version: '9.1.0.v20131115'
-
   testImplementation(project(path:':dd-java-agent:testing', configuration: 'shadow')) {
     // explicitly declared below.
-    exclude module: 'jetty-server'
+    exclude group: 'org.eclipse.jetty'
   }
   testImplementation group: 'javax.servlet', name: 'javax.servlet-api', version: '3.1.0'
   testImplementation project(':dd-java-agent:instrumentation:jetty-util')

dd-java-agent/instrumentation/jetty-client-9.1/src/main/java/datadog/trace/instrumentation/jetty_client/JettyClientDecorator.java

@@ -12,8 +12,8 @@
 import org.slf4j.LoggerFactory;
 
 public class JettyClientDecorator extends HttpClientDecorator<Request, Response> {
-  private static final MethodHandle HANDLE = createMethodHandle();
   private static final Logger LOGGER = LoggerFactory.getLogger(JettyClientDecorator.class);
+  private static final MethodHandle HANDLE = createMethodHandle();
   public static final CharSequence JETTY_CLIENT = UTF8BytesString.create("jetty-client");
   public static final JettyClientDecorator DECORATE = new JettyClientDecorator();
   public static final CharSequence HTTP_REQUEST = UTF8BytesString.create(DECORATE.operationName());
@@ -66,11 +66,13 @@ protected String getResponseHeader(Response response, String headerName) {
   }
 
   private String getHeaderValue(final HttpFields fields, final String headerName) {
-    try {
-      return (String) HANDLE.invokeExact(fields, headerName);
-    } catch (Throwable t) {
-      // probably we should log here but in case of issue we'll flood
-      // however muzzle should already protect us from falling here
+    if (HANDLE != null) {
+      try {
+        return (String) HANDLE.invokeExact(fields, headerName);
+      } catch (Throwable t) {
+        // probably we should log here but in case of issue we'll flood
+        // however muzzle should already protect us from falling here
+      }
     }
     return null;
   }

dd-java-agent/instrumentation/jetty-client-9.1/src/main/java/datadog/trace/instrumentation/jetty_client/JettyClientInstrumentation.java

@@ -91,6 +91,11 @@ public void methodAdvice(MethodTransformer transformer) {
   public String[] muzzleIgnoredClassNames() {
     return new String[] {
       "org.eclipse.jetty.http.HttpFields",
+      // add also helpers
+      packageName + ".JettyClientDecorator",
+      packageName + ".HeadersInjectAdapter",
+      packageName + ".CallbackWrapper",
+      packageName + ".SpanFinishingCompleteListener",
     };
   }