Update ApacheHttpAsync, Client, SpringWebfluxHttp

Author: sarahchen6

dd-java-agent/instrumentation/apache-httpasyncclient-4/src/main/java/datadog/trace/instrumentation/apachehttpasyncclient/ApacheHttpAsyncClientDecorator.java

@@ -4,6 +4,8 @@
 import datadog.trace.bootstrap.instrumentation.decorator.HttpClientDecorator;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.util.ArrayList;
+import java.util.List;
 import org.apache.http.Header;
 import org.apache.http.HttpResponse;
 import org.apache.http.StatusLine;
@@ -55,9 +57,13 @@ protected int status(final HttpContext context) {
 
   @Override
   protected String getRequestHeader(HttpUriRequest request, String headerName) {
-    Header header = request.getFirstHeader(headerName);
-    if (header != null) {
-      return header.getValue();
+    Header[] headers = request.getHeaders(headerName);
+    List<String> values = new ArrayList<>();
+    if (null != headers) {
+      for (Header header : headers) {
+        values.add(header.getValue());
+      }
+      return String.join(", ", values);
     }
     return null;
   }
@@ -66,9 +72,13 @@ protected String getRequestHeader(HttpUriRequest request, String headerName) {
   protected String getResponseHeader(HttpContext context, String headerName) {
     final Object responseObject = context.getAttribute(HttpCoreContext.HTTP_RESPONSE);
     if (responseObject instanceof HttpResponse) {
-      Header header = ((HttpResponse) responseObject).getFirstHeader(headerName);
-      if (header != null) {
-        return header.getValue();
+      Header[] headers = ((HttpResponse) responseObject).getHeaders(headerName);
+      List<String> values = new ArrayList<>();
+      if (null != headers) {
+        for (Header header : headers) {
+          values.add(header.getValue());
+        }
+        return String.join(", ", values);
       }
     }
     return null;

dd-java-agent/instrumentation/grizzly-client-1.9/src/main/java/datadog/trace/instrumentation/grizzly/client/ClientDecorator.java

@@ -42,7 +42,7 @@ protected int status(final Response response) {
 
   @Override
   protected String getRequestHeader(Request request, String headerName) {
-    return request.getHeaders().getFirstValue(headerName);
+    return request.getHeaders().getJoinedValue(headerName, ", ");
   }
 
   @Override

dd-java-agent/instrumentation/spring-webflux-5/src/main/java/datadog/trace/instrumentation/springwebflux/client/SpringWebfluxHttpClientDecorator.java

@@ -53,11 +53,11 @@ protected int status(final ClientResponse httpResponse) {
 
   @Override
   protected String getRequestHeader(ClientRequest request, String headerName) {
-    return request.headers().getFirst(headerName);
+    return String.join(",", request.headers().getValuesAsList(headerName));
   }
 
   @Override
   protected String getResponseHeader(ClientResponse response, String headerName) {
-    return response.headers().asHttpHeaders().getFirst(headerName);
+    return String.join(", ", response.headers().asHttpHeaders().getValuesAsList(headerName));
   }
 }