Collect WebLogic specific attributes (#81)

* Collect WebLogic middleware name, version, domain, server and application attributes

instrumentation/weblogic/build.gradle

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+plugins {
+  id "java"
+}
+
+dependencies {
+  compileOnly('javax.servlet:servlet-api:2.2')
+}

instrumentation/weblogic/src/main/java/com/splunk/opentelemetry/middleware/weblogic/WebLogicAttributeCollector.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright Splunk Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.splunk.opentelemetry.middleware.weblogic;
+
+import com.splunk.opentelemetry.javaagent.bootstrap.MiddlewareHolder;
+import java.util.HashMap;
+import java.util.Map;
+import javax.servlet.http.HttpServletRequest;
+
+public class WebLogicAttributeCollector {
+  private static final String CONTEXT_ATTRIBUTE_NAME = "otel.weblogic.attributes";
+  public static final String REQUEST_ATTRIBUTE_NAME = "otel.middleware";
+
+  public static void attachMiddlewareAttributes(HttpServletRequest servletRequest) {
+    WebLogicEntity.Request request = WebLogicEntity.Request.wrap(servletRequest);
+
+    Map<?, ?> attributes = fetchMiddlewareAttributes(request.getContext());
+    request.instance.setAttribute(REQUEST_ATTRIBUTE_NAME, attributes);
+  }
+
+  private static Map<?, ?> fetchMiddlewareAttributes(WebLogicEntity.Context context) {
+    if (context.instance == null) {
+      return null;
+    }
+
+    Object value = context.instance.getAttribute(CONTEXT_ATTRIBUTE_NAME);
+
+    if (value instanceof Map<?, ?>) {
+      return (Map<?, ?>) value;
+    }
+
+    // Do this here to avoid duplicate work
+    storeMiddlewareIdentity(context);
+
+    Map<String, String> middleware = collectMiddlewareAttributes(context);
+    context.instance.setAttribute(CONTEXT_ATTRIBUTE_NAME, middleware);
+    return middleware;
+  }
+
+  private static void storeMiddlewareIdentity(WebLogicEntity.Context context) {
+    MiddlewareHolder.trySetName("WebLogic Server");
+    MiddlewareHolder.trySetVersion(detectVersion(context));
+  }
+
+  private static Map<String, String> collectMiddlewareAttributes(WebLogicEntity.Context context) {
+    WebLogicEntity.Bean applicationBean = context.getBean();
+    WebLogicEntity.Bean webServerBean = context.getServer().getBean();
+    WebLogicEntity.Bean serverBean = webServerBean.getParent();
+    WebLogicEntity.Bean clusterBean = WebLogicEntity.Bean.wrap(serverBean.getAttribute("Cluster"));
+    WebLogicEntity.Bean domainBean = serverBean.getParent();
+
+    Map<String, String> attributes = new HashMap<>();
+    attributes.put("middleware.weblogic.domain", domainBean.getName());
+    attributes.put("middleware.weblogic.cluster", clusterBean.getName());
+    attributes.put("middleware.weblogic.server", webServerBean.getName());
+    attributes.put("middleware.weblogic.application", applicationBean.getName());
+
+    return attributes;
+  }
+
+  private static String detectVersion(WebLogicEntity.Context context) {
+    String serverInfo = context.instance.getServerInfo();
+
+    if (serverInfo != null) {
+      for (String token : serverInfo.split(" ")) {
+        if (token.length() > 0 && Character.isDigit(token.charAt(0))) {
+          return token;
+        }
+      }
+    }
+
+    return "";
+  }
+}

instrumentation/weblogic/src/main/java/com/splunk/opentelemetry/middleware/weblogic/WebLogicEntity.java

@@ -0,0 +1,266 @@
+/*
+ * Copyright Splunk Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.splunk.opentelemetry.middleware.weblogic;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import javax.servlet.ServletContext;
+import javax.servlet.ServletRequest;
+
+/** Provides wrappers around WebLogic internal class instances. */
+public class WebLogicEntity {
+  private static final MethodHandle REQUEST_GET_CONTEXT;
+  private static final MethodHandle CONTEXT_GET_MBEAN;
+  private static final MethodHandle CONTEXT_GET_SERVER;
+  private static final MethodHandle SERVER_GET_MBEAN;
+  private static final MethodHandle MBEAN_GET_PARENT;
+  private static final MethodHandle MBEAN_GET_KEY;
+  private static final Class<?> MBEAN_CLASS;
+  private static final MethodHandle MBEAN_GET_ATTRIBUTE;
+
+  static {
+    MethodHandle requestGetContext;
+    MethodHandle contextGetMBean;
+    MethodHandle contextGetServer;
+    MethodHandle serverGetMBean;
+    MethodHandle mbeanGetParent;
+    MethodHandle mbeanGetKey;
+    MethodHandle mbeanGetAttribute;
+    Class<?> mbeanClass;
+
+    try {
+      requestGetContext =
+          MethodHandles.publicLookup()
+              .findVirtual(
+                  Class.forName("weblogic.servlet.internal.ServletRequestImpl"),
+                  "getContext",
+                  MethodType.methodType(
+                      Class.forName("weblogic.servlet.internal.WebAppServletContext")));
+    } catch (Exception e) {
+      requestGetContext = null;
+    }
+
+    REQUEST_GET_CONTEXT = requestGetContext;
+
+    try {
+      contextGetMBean =
+          MethodHandles.publicLookup()
+              .findVirtual(
+                  Class.forName("weblogic.servlet.internal.WebAppServletContext"),
+                  "getMBean",
+                  MethodType.methodType(
+                      Class.forName("weblogic.management.configuration.WebAppComponentMBean")));
+    } catch (Exception e) {
+      contextGetMBean = null;
+    }
+
+    CONTEXT_GET_MBEAN = contextGetMBean;
+
+    try {
+      contextGetServer =
+          MethodHandles.publicLookup()
+              .findVirtual(
+                  Class.forName("weblogic.servlet.internal.WebAppServletContext"),
+                  "getServer",
+                  MethodType.methodType(Class.forName("weblogic.servlet.internal.HttpServer")));
+    } catch (Exception e) {
+      contextGetServer = null;
+    }
+
+    CONTEXT_GET_SERVER = contextGetServer;
+
+    try {
+      serverGetMBean =
+          MethodHandles.publicLookup()
+              .findVirtual(
+                  Class.forName("weblogic.servlet.internal.HttpServer"),
+                  "getMBean",
+                  MethodType.methodType(
+                      Class.forName("weblogic.management.configuration.WebServerMBean")));
+    } catch (Exception e) {
+      serverGetMBean = null;
+    }
+
+    SERVER_GET_MBEAN = serverGetMBean;
+
+    try {
+      mbeanGetParent =
+          MethodHandles.publicLookup()
+              .findVirtual(
+                  Class.forName("weblogic.descriptor.DescriptorBean"),
+                  "getParentBean",
+                  MethodType.methodType(Class.forName("weblogic.descriptor.DescriptorBean")));
+    } catch (Exception e) {
+      mbeanGetParent = null;
+    }
+
+    MBEAN_GET_PARENT = mbeanGetParent;
+
+    try {
+      mbeanGetKey =
+          MethodHandles.publicLookup()
+              .findVirtual(
+                  Class.forName("weblogic.descriptor.internal.AbstractDescriptorBean"),
+                  "_getKey",
+                  MethodType.methodType(Object.class));
+    } catch (Exception e) {
+      mbeanGetKey = null;
+    }
+
+    MBEAN_GET_KEY = mbeanGetKey;
+
+    try {
+      mbeanGetAttribute =
+          MethodHandles.publicLookup()
+              .findVirtual(
+                  Class.forName("javax.management.DynamicMBean"),
+                  "getAttribute",
+                  MethodType.methodType(Object.class, String.class));
+    } catch (Exception e) {
+      mbeanGetAttribute = null;
+    }
+
+    MBEAN_GET_ATTRIBUTE = mbeanGetAttribute;
+
+    try {
+      mbeanClass = Class.forName("weblogic.management.WebLogicMBean");
+    } catch (Exception e) {
+      mbeanClass = null;
+    }
+
+    MBEAN_CLASS = mbeanClass;
+  }
+
+  public static class Request {
+    private static final Request NULL = new Request(null);
+
+    public final ServletRequest instance;
+
+    private Request(ServletRequest instance) {
+      this.instance = instance;
+    }
+
+    public static Request wrap(ServletRequest instance) {
+      return instance != null ? new Request(instance) : NULL;
+    }
+
+    public Context getContext() {
+      try {
+        return Context.wrap(
+            REQUEST_GET_CONTEXT != null ? REQUEST_GET_CONTEXT.invoke(instance) : null);
+      } catch (Throwable throwable) {
+        return Context.NULL;
+      }
+    }
+  }
+
+  public static class Context {
+    private static final Context NULL = new Context(null);
+
+    public final ServletContext instance;
+
+    private Context(ServletContext instance) {
+      this.instance = instance;
+    }
+
+    public static Context wrap(Object instance) {
+      return instance instanceof ServletContext ? new Context((ServletContext) instance) : NULL;
+    }
+
+    public Bean getBean() {
+      try {
+        return Bean.wrap(CONTEXT_GET_MBEAN != null ? CONTEXT_GET_MBEAN.invoke(instance) : null);
+      } catch (Throwable throwable) {
+        return Bean.NULL;
+      }
+    }
+
+    public Server getServer() {
+      try {
+        return Server.wrap(CONTEXT_GET_SERVER != null ? CONTEXT_GET_SERVER.invoke(instance) : null);
+      } catch (Throwable throwable) {
+        return Server.NULL;
+      }
+    }
+  }
+
+  public static class Server {
+    private static final Server NULL = new Server(null);
+
+    public final Object instance;
+
+    private Server(Object instance) {
+      this.instance = instance;
+    }
+
+    public static Server wrap(Object instance) {
+      return instance != null ? new Server(instance) : NULL;
+    }
+
+    public Bean getBean() {
+      try {
+        return Bean.wrap(SERVER_GET_MBEAN != null ? SERVER_GET_MBEAN.invoke(instance) : null);
+      } catch (Throwable throwable) {
+        return Bean.NULL;
+      }
+    }
+  }
+
+  public static class Bean {
+    private static final Bean NULL = new Bean(null);
+
+    public final Object instance;
+
+    private Bean(Object instance) {
+      this.instance = instance;
+    }
+
+    public static Bean wrap(Object instance) {
+      return instance != null
+              && MBEAN_CLASS != null
+              && MBEAN_CLASS.isAssignableFrom(instance.getClass())
+          ? new Bean(instance)
+          : NULL;
+    }
+
+    public String getName() {
+      try {
+        Object key = MBEAN_GET_KEY != null ? MBEAN_GET_KEY.invoke(instance) : null;
+        return key != null ? key.toString() : null;
+      } catch (Throwable throwable) {
+        return null;
+      }
+    }
+
+    public Bean getParent() {
+      try {
+        return Bean.wrap(MBEAN_GET_PARENT != null ? MBEAN_GET_PARENT.invoke(instance) : null);
+      } catch (Throwable throwable) {
+        return Bean.NULL;
+      }
+    }
+
+    public Object getAttribute(String name) {
+      try {
+        return MBEAN_GET_ATTRIBUTE != null ? MBEAN_GET_ATTRIBUTE.invoke(instance, name) : null;
+      } catch (Throwable throwable) {
+        return null;
+      }
+    }
+  }
+}