New agent instrumentation for Apache Sling

instrumentation/sling/javaagent/build.gradle.kts

@@ -0,0 +1,12 @@
+plugins {
+  id("otel.javaagent-instrumentation")
+}
+
+dependencies {
+  bootstrap(project(":instrumentation:executors:bootstrap"))
+  implementation(project(":instrumentation:servlet:servlet-3.0:javaagent"))
+  bootstrap(project(":instrumentation:servlet:servlet-common:bootstrap"))
+  api(project(":instrumentation:servlet:servlet-common:javaagent"))
+  compileOnly("javax.servlet:javax.servlet-api:3.1.0")
+  library("org.apache.sling:org.apache.sling.api:2.0.6") // first non-incubator release
+}

instrumentation/sling/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/sling/ServletResolverInstrumentation.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.instrumentation.sling;
+
+import static io.opentelemetry.javaagent.extension.matcher.AgentElementMatchers.implementsInterface;
+import static io.opentelemetry.javaagent.instrumentation.sling.SlingSingletons.REQUEST_ATTR_RESOLVED_SERVLET_NAME;
+import static net.bytebuddy.matcher.ElementMatchers.isMethod;
+import static net.bytebuddy.matcher.ElementMatchers.named;
+import static net.bytebuddy.matcher.ElementMatchers.takesArgument;
+import static net.bytebuddy.matcher.ElementMatchers.takesArguments;
+
+import io.opentelemetry.context.Context;
+import io.opentelemetry.context.Scope;
+import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
+import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
+import javax.servlet.Servlet;
+import net.bytebuddy.asm.Advice;
+import net.bytebuddy.description.type.TypeDescription;
+import net.bytebuddy.matcher.ElementMatcher;
+import org.apache.sling.api.SlingHttpServletRequest;
+
+public class ServletResolverInstrumentation implements TypeInstrumentation {
+
+  @Override
+  public ElementMatcher<TypeDescription> typeMatcher() {
+    return implementsInterface(named("org.apache.sling.api.servlets.ServletResolver"));
+  }
+
+  @Override
+  public void transform(TypeTransformer transformer) {
+    transformer.applyAdviceToMethod(
+        isMethod()
+            .and(named("resolveServlet"))
+            .and(takesArguments(1))
+            .and(takesArgument(0, named("org.apache.sling.api.SlingHttpServletRequest"))),
+        this.getClass().getName() + "$ResolveServletAdvice");
+  }
+
+  @SuppressWarnings("unused")
+  public static class ResolveServletAdvice {
+
+    @Advice.OnMethodExit(suppress = Throwable.class, onThrowable = Throwable.class)
+    public static void onExit(
+        @Advice.Argument(0) SlingHttpServletRequest request,
+        @Advice.Return Servlet servlet,
+        @Advice.Thrown Throwable throwable,
+        @Advice.Local("otelContext") Context context,
+        @Advice.Local("otelScope") Scope scope) {
+
+      String name = null;
+
+      if (servlet.getServletConfig() != null) {
+        name = servlet.getServletConfig().getServletName();
+      }
+      if (name == null || name.isEmpty()) {
+        name = servlet.getServletInfo();
+      }
+      if (name == null || name.isEmpty()) {
+        name = servlet.getClass().getName();
+      }
+
+      request.setAttribute(REQUEST_ATTR_RESOLVED_SERVLET_NAME, name);
+    }
+  }
+}

instrumentation/sling/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/sling/SlingInstrumentationModule.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.instrumentation.sling;
+
+import com.google.auto.service.AutoService;
+import io.opentelemetry.javaagent.extension.instrumentation.InstrumentationModule;
+import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
+import java.util.Arrays;
+import java.util.List;
+
+@AutoService(InstrumentationModule.class)
+public class SlingInstrumentationModule extends InstrumentationModule {
+
+  public SlingInstrumentationModule() {
+    super("sling", "sling-1.0");
+  }
+
+  @Override
+  public List<TypeInstrumentation> typeInstrumentations() {
+    return Arrays.asList(
+        new ServletResolverInstrumentation(), new SlingSafeMethodsServletInstrumentation());
+  }
+}

instrumentation/sling/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/sling/SlingSafeMethodsServletInstrumentation.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.instrumentation.sling;
+
+import static io.opentelemetry.javaagent.extension.matcher.AgentElementMatchers.hasClassesNamed;
+import static io.opentelemetry.javaagent.extension.matcher.AgentElementMatchers.implementsInterface;
+import static io.opentelemetry.javaagent.instrumentation.sling.SlingSingletons.REQUEST_ATTR_RESOLVED_SERVLET_NAME;
+import static io.opentelemetry.javaagent.instrumentation.sling.SlingSingletons.helper;
+import static net.bytebuddy.matcher.ElementMatchers.named;
+import static net.bytebuddy.matcher.ElementMatchers.takesArgument;
+import static net.bytebuddy.matcher.ElementMatchers.takesArguments;
+
+import io.opentelemetry.context.Context;
+import io.opentelemetry.context.Scope;
+import io.opentelemetry.instrumentation.api.semconv.http.HttpServerRoute;
+import io.opentelemetry.instrumentation.api.semconv.http.HttpServerRouteSource;
+import io.opentelemetry.javaagent.bootstrap.Java8BytecodeBridge;
+import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
+import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
+import javax.servlet.ServletRequest;
+import net.bytebuddy.asm.Advice;
+import net.bytebuddy.description.type.TypeDescription;
+import net.bytebuddy.matcher.ElementMatcher;
+import org.apache.sling.api.SlingHttpServletRequest;
+
+public class SlingSafeMethodsServletInstrumentation implements TypeInstrumentation {
+  @Override
+  public ElementMatcher<TypeDescription> typeMatcher() {
+    return implementsInterface(named("javax.servlet.Servlet"));
+  }
+
+  @Override
+  public ElementMatcher<ClassLoader> classLoaderOptimization() {
+    return hasClassesNamed("org.apache.sling.api.SlingHttpServletRequest");
+  }
+
+  @Override
+  public void transform(TypeTransformer transformer) {
+
+    String adviceClassName = this.getClass().getName() + "$ServiceServletAdvice";
+    transformer.applyAdviceToMethod(
+        named("service")
+            .and(takesArguments(2))
+            .and(takesArgument(0, named("javax.servlet.ServletRequest")))
+            .and(takesArgument(1, named("javax.servlet.ServletResponse"))),
+        adviceClassName);
+  }
+
+  @SuppressWarnings("unused")
+  public static class ServiceServletAdvice {
+    @Advice.OnMethodEnter(suppress = Throwable.class)
+    public static void onEnter(
+        @Advice.Argument(0) ServletRequest request,
+        @Advice.Local("otelContext") Context context,
+        @Advice.Local("otelScope") Scope scope) {
+
+      if (!(request instanceof SlingHttpServletRequest)) {
+        return;
+      }
+
+      SlingHttpServletRequest slingRequest = (SlingHttpServletRequest) request;
+
+      Context parentContext = Java8BytecodeBridge.currentContext();
+
+      if (!helper().shouldStart(parentContext, slingRequest)) {
+        return;
+      }
+
+      // written by ServletResolverInstrumentation
+      Object servletName = request.getAttribute(REQUEST_ATTR_RESOLVED_SERVLET_NAME);
+      if (!(servletName instanceof String)) {
+        return;
+      }
+
+      // TODO - figure out why don't we have matches for all requests and find a better way to
+      // filter
+      context = helper().start(parentContext, slingRequest);
+      scope = context.makeCurrent();
+
+      // ensure that the top-level route is Sling-specific
+      HttpServerRoute.update(context, HttpServerRouteSource.CONTROLLER, (String) servletName);
+
+      // cleanup and ensure we don't have reuse the resolved Servlet name by accident for other
+      // requests
+      request.removeAttribute(REQUEST_ATTR_RESOLVED_SERVLET_NAME);
+    }
+
+    @Advice.OnMethodExit(suppress = Throwable.class, onThrowable = Throwable.class)
+    public static void onExit(
+        @Advice.Argument(0) ServletRequest request,
+        @Advice.Thrown Throwable throwable,
+        @Advice.Local("otelContext") Context context,
+        @Advice.Local("otelScope") Scope scope) {
+
+      if (scope == null) {
+        return;
+      }
+      scope.close();
+
+      SlingHttpServletRequest slingRequest = (SlingHttpServletRequest) request;
+      helper().end(context, slingRequest, null, throwable);
+    }
+  }
+}

instrumentation/sling/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/sling/SlingSingletons.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.instrumentation.sling;
+
+import io.opentelemetry.api.GlobalOpenTelemetry;
+import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
+import io.opentelemetry.instrumentation.api.instrumenter.SpanNameExtractor;
+import org.apache.sling.api.SlingHttpServletRequest;
+
+public final class SlingSingletons {
+  private static final String INSTRUMENTATION_NAME = "io.opentelemetry.sling-1.0";
+
+  static final String REQUEST_ATTR_RESOLVED_SERVLET_NAME =
+      INSTRUMENTATION_NAME + ".resolvedServletName";
+
+  private static final SpanNameExtractor<SlingHttpServletRequest> SPAN_NAME_EXTRACTOR =
+      s -> (String) s.getAttribute(REQUEST_ATTR_RESOLVED_SERVLET_NAME);
+  private static final Instrumenter<SlingHttpServletRequest, Void> INSTRUMENTER =
+      Instrumenter.<SlingHttpServletRequest, Void>builder(
+              GlobalOpenTelemetry.get(), INSTRUMENTATION_NAME, SPAN_NAME_EXTRACTOR)
+          .buildInstrumenter();
+
+  public static Instrumenter<SlingHttpServletRequest, Void> helper() {
+    return INSTRUMENTER;
+  }
+
+  private SlingSingletons() {}
+}

settings.gradle.kts

@@ -523,6 +523,7 @@ include(":instrumentation:servlet:servlet-5.0:tomcat-testing")
 include(":instrumentation:servlet:servlet-common:bootstrap")
 include(":instrumentation:servlet:servlet-common:javaagent")
 include(":instrumentation:servlet:servlet-javax-common:javaagent")
+include(":instrumentation:sling:javaagent")
 include(":instrumentation:spark-2.3:javaagent")
 include(":instrumentation:spring:spring-batch-3.0:javaagent")
 include(":instrumentation:spring:spring-boot-actuator-autoconfigure-2.0:javaagent")