Update servlet-2 to new agent api

dd-java-agent/instrumentation/servlet-2/src/main/java/datadog/trace/instrumentation/servlet2/AbstractServlet2Instrumentation.java

@@ -26,7 +26,6 @@ public abstract class AbstractServlet2Instrumentation extends Instrumenter.Defau
       "datadog.trace.agent.decorator.HttpServerDecorator",
       packageName + ".Servlet2Decorator",
       packageName + ".HttpServletRequestExtractAdapter",
-      packageName + ".HttpServletRequestExtractAdapter$MultivaluedMapFlatIterator",
       packageName + ".StatusSavingHttpServletResponseWrapper",
     };
   }

dd-java-agent/instrumentation/servlet-2/src/main/java/datadog/trace/instrumentation/servlet2/HttpServletRequestExtractAdapter.java

@@ -1,14 +1,7 @@
 package datadog.trace.instrumentation.servlet2;
 
-import io.opentracing.propagation.TextMap;
+import datadog.trace.instrumentation.api.AgentPropagation;
-import java.util.AbstractMap;
+import java.util.Collections;
-import java.util.ArrayList;
-import java.util.Enumeration;
-import java.util.HashMap;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
 import javax.servlet.http.HttpServletRequest;
 
 /**
@@ -17,80 +10,19 @@ import javax.servlet.http.HttpServletRequest;
  * @author Pavol Loffay
  */
 // FIXME:  This code is duplicated in several places.  Extract to a common dependency.
-public class HttpServletRequestExtractAdapter implements TextMap {
+public class HttpServletRequestExtractAdapter
+    implements AgentPropagation.Getter<HttpServletRequest> {
 
-  private final Map<String, List<String>> headers;
+  public static final HttpServletRequestExtractAdapter GETTER =
+      new HttpServletRequestExtractAdapter();
 
-  public HttpServletRequestExtractAdapter(final HttpServletRequest httpServletRequest) {
+  @Override
-    headers = servletHeadersToMultiMap(httpServletRequest);
+  public Iterable<String> keys(final HttpServletRequest carrier) {
+    return Collections.list(carrier.getHeaderNames());
   }
 
   @Override
-  public Iterator<Map.Entry<String, String>> iterator() {
+  public String get(final HttpServletRequest carrier, final String key) {
-    return new MultivaluedMapFlatIterator<>(headers.entrySet());
+    return carrier.getHeader(key);
-  }
-
-  @Override
-  public void put(final String key, final String value) {
-    throw new UnsupportedOperationException("This class should be used only with Tracer.inject()!");
-  }
-
-  protected Map<String, List<String>> servletHeadersToMultiMap(
-      final HttpServletRequest httpServletRequest) {
-    final Map<String, List<String>> headersResult = new HashMap<>();
-
-    final Enumeration<?> headerNamesIt = httpServletRequest.getHeaderNames();
-    while (headerNamesIt.hasMoreElements()) {
-      final String headerName = headerNamesIt.nextElement().toString();
-
-      final Enumeration<?> valuesIt = httpServletRequest.getHeaders(headerName);
-      final List<String> valuesList = new ArrayList<>(1);
-      while (valuesIt.hasMoreElements()) {
-        valuesList.add(valuesIt.nextElement().toString());
-      }
-
-      headersResult.put(headerName, valuesList);
-    }
-
-    return headersResult;
-  }
-
-  public static final class MultivaluedMapFlatIterator<K, V> implements Iterator<Map.Entry<K, V>> {
-
-    private final Iterator<Map.Entry<K, List<V>>> mapIterator;
-    private Map.Entry<K, List<V>> mapEntry;
-    private Iterator<V> listIterator;
-
-    public MultivaluedMapFlatIterator(final Set<Map.Entry<K, List<V>>> multiValuesEntrySet) {
-      mapIterator = multiValuesEntrySet.iterator();
-    }
-
-    @Override
-    public boolean hasNext() {
-      if (listIterator != null && listIterator.hasNext()) {
-        return true;
-      }
-
-      return mapIterator.hasNext();
-    }
-
-    @Override
-    public Map.Entry<K, V> next() {
-      if (mapEntry == null || (!listIterator.hasNext() && mapIterator.hasNext())) {
-        mapEntry = mapIterator.next();
-        listIterator = mapEntry.getValue().iterator();
-      }
-
-      if (listIterator.hasNext()) {
-        return new AbstractMap.SimpleImmutableEntry<>(mapEntry.getKey(), listIterator.next());
-      } else {
-        return new AbstractMap.SimpleImmutableEntry<>(mapEntry.getKey(), null);
-      }
-    }
-
-    @Override
-    public void remove() {
-      throw new UnsupportedOperationException();
-    }
   }
 }

dd-java-agent/instrumentation/servlet-2/src/main/java/datadog/trace/instrumentation/servlet2/Servlet2Advice.java

@@ -1,16 +1,18 @@
 package datadog.trace.instrumentation.servlet2;
 
 import static datadog.trace.agent.decorator.HttpServerDecorator.DD_SPAN_ATTRIBUTE;
+import static datadog.trace.instrumentation.api.AgentTracer.activateSpan;
+import static datadog.trace.instrumentation.api.AgentTracer.activeSpan;
+import static datadog.trace.instrumentation.api.AgentTracer.propagate;
+import static datadog.trace.instrumentation.api.AgentTracer.startSpan;
+import static datadog.trace.instrumentation.servlet2.HttpServletRequestExtractAdapter.GETTER;
 import static datadog.trace.instrumentation.servlet2.Servlet2Decorator.DECORATE;
 
 import datadog.trace.api.DDTags;
-import datadog.trace.context.TraceScope;
+import datadog.trace.instrumentation.api.AgentScope;
-import io.opentracing.Scope;
+import datadog.trace.instrumentation.api.AgentSpan;
-import io.opentracing.Span;
+import datadog.trace.instrumentation.api.AgentSpan.Context;
-import io.opentracing.SpanContext;
-import io.opentracing.propagation.Format;
 import io.opentracing.tag.Tags;
-import io.opentracing.util.GlobalTracer;
 import java.security.Principal;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
@@ -22,7 +24,7 @@ import net.bytebuddy.implementation.bytecode.assign.Assigner;
 public class Servlet2Advice {
 
   @Advice.OnMethodEnter(suppress = Throwable.class)
-  public static Scope startSpan(
+  public static AgentScope onEnter(
       @Advice.This final Object servlet,
       @Advice.Argument(0) final ServletRequest req,
       @Advice.Argument(value = 1, readOnly = false, typing = Assigner.Typing.DYNAMIC)
@@ -38,30 +40,20 @@ public class Servlet2Advice {
     }
 
     final HttpServletRequest httpServletRequest = (HttpServletRequest) req;
-    final SpanContext extractedContext =
+    final Context extractedContext = propagate().extract(httpServletRequest, GETTER);
-        GlobalTracer.get()
-            .extract(
-                Format.Builtin.HTTP_HEADERS,
-                new HttpServletRequestExtractAdapter(httpServletRequest));
 
-    final Scope scope =
+    final AgentSpan span =
-        GlobalTracer.get()
+        startSpan("servlet.request", extractedContext)
-            .buildSpan("servlet.request")
+            .setTag("span.origin.type", servlet.getClass().getName());
-            .ignoreActiveSpan()
-            .asChildOf(extractedContext)
-            .withTag("span.origin.type", servlet.getClass().getName())
-            .startActive(true);
 
-    final Span span = scope.span();
     DECORATE.afterStart(span);
     DECORATE.onConnection(span, httpServletRequest);
     DECORATE.onRequest(span, httpServletRequest);
 
-    if (scope instanceof TraceScope) {
-      ((TraceScope) scope).setAsyncPropagation(true);
-    }
-
     req.setAttribute(DD_SPAN_ATTRIBUTE, span);
+
+    final AgentScope scope = activateSpan(span, true);
+    scope.setAsyncPropagation(true);
     return scope;
   }
 
@@ -69,10 +61,10 @@ public class Servlet2Advice {
   public static void stopSpan(
       @Advice.Argument(0) final ServletRequest request,
       @Advice.Argument(1) final ServletResponse response,
-      @Advice.Enter final Scope scope,
+      @Advice.Enter final AgentScope scope,
       @Advice.Thrown final Throwable throwable) {
     // Set user.principal regardless of who created this span.
-    final Span currentSpan = GlobalTracer.get().activeSpan();
+    final AgentSpan currentSpan = activeSpan();
     if (currentSpan != null) {
       if (request instanceof HttpServletRequest) {
         final Principal principal = ((HttpServletRequest) request).getUserPrincipal();
@@ -83,22 +75,20 @@ public class Servlet2Advice {
     }
 
     if (scope != null) {
-      final Span span = scope.span();
+      final AgentSpan span = scope.span();
       DECORATE.onResponse(span, response);
       if (throwable != null) {
         if (response instanceof StatusSavingHttpServletResponseWrapper
             && ((StatusSavingHttpServletResponseWrapper) response).status
                 == HttpServletResponse.SC_OK) {
           // exception was thrown but status code wasn't set
-          Tags.HTTP_STATUS.set(span, 500);
+          span.setTag(Tags.HTTP_STATUS.getKey(), 500);
         }
         DECORATE.onError(span, throwable);
       }
       DECORATE.beforeFinish(span);
 
-      if (scope instanceof TraceScope) {
+      scope.setAsyncPropagation(false);
-        ((TraceScope) scope).setAsyncPropagation(false);
-      }
       scope.close();
     }
   }

dd-java-agent/instrumentation/servlet-2/src/main/java/datadog/trace/instrumentation/servlet2/Servlet2Decorator.java

@@ -1,7 +1,7 @@
 package datadog.trace.instrumentation.servlet2;
 
 import datadog.trace.agent.decorator.HttpServerDecorator;
-import io.opentracing.Span;
+import datadog.trace.instrumentation.api.AgentSpan;
 import java.net.URI;
 import java.net.URISyntaxException;
 import javax.servlet.ServletResponse;
@@ -58,7 +58,7 @@ public class Servlet2Decorator
   }
 
   @Override
-  public Span onRequest(final Span span, final HttpServletRequest request) {
+  public AgentSpan onRequest(final AgentSpan span, final HttpServletRequest request) {
     assert span != null;
     if (request != null) {
       span.setTag("servlet.context", request.getContextPath());