Optionally prevent undertow from setting http.route

dd-java-agent/instrumentation/undertow/undertow-2.0/src/main/java/datadog/trace/instrumentation/undertow/ServletInstrumentation.java

@@ -12,6 +12,7 @@
 import com.google.auto.service.AutoService;
 import datadog.trace.agent.tooling.Instrumenter;
 import datadog.trace.agent.tooling.InstrumenterModule;
+import datadog.trace.api.Config;
 import datadog.trace.bootstrap.instrumentation.api.AgentScope;
 import datadog.trace.bootstrap.instrumentation.api.AgentSpan;
 import io.undertow.server.HttpServerExchange;
@@ -70,7 +71,8 @@ public static void enter(
         String relativePath = exchange.getRelativePath();
 
         ServletPathMatch servletPathMatch = servletRequestContext.getServletPathMatch();
-        if (servletPathMatch != null
+        if (!Config.get().isUndertowIgnoreHttpRouteEnabled()
+            && servletPathMatch != null
             && servletPathMatch.getMappingMatch() != MappingMatch.DEFAULT) {
           // Set the route unless the mapping match is default, this way we prevent setting route
           // for a non-existing resource. Otherwise, it'd set a non-existing resource name with

dd-java-agent/instrumentation/undertow/undertow-2.0/src/test/groovy/UndertowDispatcherTest.groovy

@@ -207,7 +207,7 @@ abstract class UndertowDispatcherTest extends HttpServerTest<Undertow> {
   }
 }
 
-class UndertowDispatcherV0ForkedTest extends UndertowDispatcherTest {
+class UndertowDispatcherV0Test extends UndertowDispatcherTest {
   @Override
   int version() {
     return 0

dd-java-agent/instrumentation/undertow/undertow-2.0/src/test/groovy/UndertowServletTest.groovy

@@ -10,6 +10,7 @@ import io.undertow.servlet.api.DeploymentInfo
 import io.undertow.servlet.api.DeploymentManager
 import io.undertow.servlet.api.ServletContainer
 import io.undertow.servlet.api.ServletInfo
+import spock.lang.IgnoreIf
 
 import javax.servlet.MultipartConfigElement
 
@@ -157,6 +158,9 @@ abstract class UndertowServletTest extends HttpServerTest<Undertow> {
 
   @Override
   String expectedResourceName(ServerEndpoint endpoint, String method, URI address) {
+    if (!generateHttpRoute()) {
+      return super.expectedResourceName(endpoint, method, address)
+    }
     if (endpoint.status == 404 && endpoint.path == "/not-found") {
       return "404"
     } else if (endpoint.hasPathParam) {
@@ -198,8 +202,15 @@ abstract class UndertowServletTest extends HttpServerTest<Undertow> {
     }
   }
 
+  def generateHttpRoute() {
+    true
+  }
+
   @Override
   Serializable expectedServerSpanRoute(ServerEndpoint endpoint) {
+    if (!generateHttpRoute()) {
+      return null
+    }
     switch (endpoint) {
       case LOGIN:
       case NOT_FOUND:
@@ -211,6 +222,7 @@ abstract class UndertowServletTest extends HttpServerTest<Undertow> {
     }
   }
 
+  @IgnoreIf({ !instance.generateHttpRoute() })
   def "test not-here"() {
     setup:
     def request = request(NOT_HERE, method, body).build()
@@ -257,7 +269,19 @@ abstract class UndertowServletTest extends HttpServerTest<Undertow> {
   }
 }
 
-class UndertowServletV0ForkedTest extends UndertowServletTest implements TestingGenericHttpNamingConventions.ServerV0 {
+class UndertowServletV0Test extends UndertowServletTest implements TestingGenericHttpNamingConventions.ServerV0 {
+}
+class UndertowServletNoHttpRouteTest extends UndertowServletTest implements TestingGenericHttpNamingConventions.ServerV0 {
+  @Override
+  def generateHttpRoute() {
+    false
+  }
+
+  @Override
+  protected void configurePreAgent() {
+    super.configurePreAgent()
+    injectSysConfig("trace.undertow.ignore.http.route", "true")
+  }
 }
 
 class UndertowServletV1ForkedTest extends UndertowServletTest implements TestingGenericHttpNamingConventions.ServerV1 {

dd-trace-api/src/main/java/datadog/trace/api/config/TraceInstrumentationConfig.java

@@ -143,6 +143,9 @@ public final class TraceInstrumentationConfig {
   public static final String JAX_RS_ADDITIONAL_ANNOTATIONS = "trace.jax-rs.additional.annotations";
   /** If set, the instrumentation will set its resource name on the local root too. */
   public static final String AXIS_PROMOTE_RESOURCE_NAME = "trace.axis.promote.resource-name";
+  /** If explicitly set to true, undertow won't set the `http.route` tag. */
+  public static final String UNDERTOW_IGNORE_HTTP_ROUTE =
+      "trace.undertow.ignore.http.route";
 
   private TraceInstrumentationConfig() {}
 }

internal-api/src/main/java/datadog/trace/api/Config.java

@@ -386,6 +386,7 @@
 import static datadog.trace.api.config.TraceInstrumentationConfig.SPARK_APP_NAME_AS_SERVICE;
 import static datadog.trace.api.config.TraceInstrumentationConfig.SPARK_TASK_HISTOGRAM_ENABLED;
 import static datadog.trace.api.config.TraceInstrumentationConfig.SPRING_DATA_REPOSITORY_INTERFACE_RESOURCE_NAME;
+import static datadog.trace.api.config.TraceInstrumentationConfig.UNDERTOW_IGNORE_HTTP_ROUTE;
 import static datadog.trace.api.config.TracerConfig.AGENT_HOST;
 import static datadog.trace.api.config.TracerConfig.AGENT_NAMED_PIPE;
 import static datadog.trace.api.config.TracerConfig.AGENT_PORT_LEGACY;
@@ -929,6 +930,8 @@ static class HostNameHolder {
 
   private final boolean telemetryDebugRequestsEnabled;
 
+  private final boolean undertowIgnoreHttpRouteEnabled;
+
   // Read order: System Properties -> Env Variables, [-> properties file], [-> default value]
   private Config() {
     this(ConfigProvider.createDefault());
@@ -2032,6 +2035,9 @@ PROFILING_DATADOG_PROFILER_ENABLED, isDatadogProfilerSafeInCurrentEnvironment())
 
     axisPromoteResourceName = configProvider.getBoolean(AXIS_PROMOTE_RESOURCE_NAME, false);
 
+    this.undertowIgnoreHttpRouteEnabled =
+        configProvider.getBoolean(UNDERTOW_IGNORE_HTTP_ROUTE, false);
+
     this.traceFlushIntervalSeconds =
         configProvider.getFloat(
             TracerConfig.TRACE_FLUSH_INTERVAL, ConfigDefaults.DEFAULT_TRACE_FLUSH_INTERVAL);
@@ -3395,6 +3401,10 @@ public boolean isAxisPromoteResourceName() {
     return axisPromoteResourceName;
   }
 
+  public boolean isUndertowIgnoreHttpRouteEnabled() {
+    return undertowIgnoreHttpRouteEnabled;
+  }
+
   /** @return A map of tags to be applied only to the local application root span. */
   public Map<String, Object> getLocalRootSpanTags() {
     final Map<String, String> runtimeTags = getRuntimeTags();