Add telemetry for /extensionList/ URL

core/src/main/java/hudson/Functions.java

@@ -2186,12 +2186,14 @@ public static Locale getCurrentLocale() {
     /**
      * Generate a series of {@code <script>} tags to include {@code script.js}
      * from {@link ConsoleAnnotatorFactory}s and {@link ConsoleAnnotationDescriptor}s.
+     *
+     * @see hudson.console.ConsoleAnnotatorFactory.RootAction
      */
     public static String generateConsoleAnnotationScriptAndStylesheet() {
         String cp = Stapler.getCurrentRequest2().getContextPath() + Jenkins.RESOURCE_PATH;
         StringBuilder buf = new StringBuilder();
         for (ConsoleAnnotatorFactory f : ConsoleAnnotatorFactory.all()) {
-            String path = cp + "/extensionList/" + ConsoleAnnotatorFactory.class.getName() + "/" + f.getClass().getName();
+            String path = cp + "/" + ConsoleAnnotatorFactory.class.getName() + "/" + f.getClass().getName();
             if (f.hasScript())
                 buf.append("<script src='").append(path).append("/script.js'></script>");
             if (f.hasStylesheet())

core/src/main/java/hudson/console/ConsoleAnnotatorFactory.java

@@ -27,6 +27,7 @@
 import hudson.Extension;
 import hudson.ExtensionList;
 import hudson.ExtensionPoint;
+import hudson.model.InvisibleAction;
 import hudson.model.Run;
 import jakarta.servlet.ServletException;
 import java.io.IOException;
@@ -35,6 +36,8 @@
 import java.net.URL;
 import java.util.concurrent.TimeUnit;
 import org.jvnet.tiger_types.Types;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.NoExternalUse;
 import org.kohsuke.stapler.StaplerRequest2;
 import org.kohsuke.stapler.StaplerResponse2;
 import org.kohsuke.stapler.WebMethod;
@@ -129,4 +132,24 @@ public void doStyleCss(StaplerRequest2 req, StaplerResponse2 rsp) throws IOExcep
     public static ExtensionList<ConsoleAnnotatorFactory> all() {
         return ExtensionList.lookup(ConsoleAnnotatorFactory.class);
     }
+
+    /**
+     * This action makes {@link hudson.console.ConsoleAnnotatorFactory} instances accessible via HTTP.
+     *
+     * @see hudson.Functions#generateConsoleAnnotationScriptAndStylesheet
+     * @see ConsoleAnnotatorFactory#hasStylesheet()
+     * @see ConsoleAnnotatorFactory#hasScript()
+     */
+    @Restricted(NoExternalUse.class)
+    @Extension
+    public static class RootAction extends InvisibleAction implements hudson.model.RootAction {
+        @Override
+        public String getUrlName() {
+            return ConsoleAnnotatorFactory.class.getName();
+        }
+
+        public ConsoleAnnotatorFactory<?> getDynamic(String className) {
+            return all().getDynamic(className);
+        }
+    }
 }

core/src/main/java/jenkins/diagnosis/MemoryUsageMonitorAction.java

@@ -0,0 +1,53 @@
+/*
+ * The MIT License
+ *
+ * Copyright (c) 2025, CloudBees, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package jenkins.diagnosis;
+
+import hudson.Extension;
+import hudson.ExtensionList;
+import hudson.diagnosis.MemoryUsageMonitor;
+import hudson.model.InvisibleAction;
+import hudson.model.RootAction;
+import jenkins.model.Jenkins;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.NoExternalUse;
+
+/**
+ * Expose {@link hudson.diagnosis.MemoryUsageMonitor#heap} at the {@code /hudson.diagnosis.MemoryUsageMonitor/heap} URL.
+ *
+ * @since TODO
+ */
+@Extension
+@Restricted(NoExternalUse.class)
+public class MemoryUsageMonitorAction extends InvisibleAction implements RootAction {
+    @Override
+    public String getUrlName() {
+        return MemoryUsageMonitorAction.class.getName();
+    }
+
+    public MemoryUsageMonitor.MemoryGroup getHeap() {
+        Jenkins.get().checkAnyPermission(Jenkins.SYSTEM_READ, Jenkins.MANAGE);
+        return ExtensionList.lookupSingleton(MemoryUsageMonitor.class).heap;
+    }
+}

core/src/main/java/jenkins/model/Jenkins.java

@@ -2808,11 +2808,13 @@ public <T> ExtensionList<T> getExtensionList(Class<T> extensionType) {
     }
 
     /**
-     * Used to bind {@link ExtensionList}s to URLs.
+     * Formerly used to bind {@link ExtensionList}s to URLs.
+     * <p>
+     *     Currently handled by {@link jenkins.telemetry.impl.HttpExtensionList.ExtensionListRootAction}.
+     * </p>
      *
      * @since 1.349
      */
-    @StaplerDispatchable
     public ExtensionList getExtensionList(String extensionType) throws ClassNotFoundException {
         return getExtensionList(pluginManager.uberClassLoader.loadClass(extensionType));
     }

core/src/main/java/jenkins/telemetry/impl/HttpExtensionList.java

@@ -0,0 +1,124 @@
+/*
+ * The MIT License
+ *
+ * Copyright (c) 2025, CloudBees, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package jenkins.telemetry.impl;
+
+import static java.util.logging.Level.FINE;
+
+import edu.umd.cs.findbugs.annotations.NonNull;
+import hudson.Extension;
+import hudson.ExtensionList;
+import hudson.model.InvisibleAction;
+import hudson.model.RootAction;
+import java.time.LocalDate;
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.logging.Logger;
+import jenkins.model.Jenkins;
+import jenkins.telemetry.Telemetry;
+import net.sf.json.JSONObject;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.NoExternalUse;
+import org.kohsuke.stapler.Stapler;
+import org.kohsuke.stapler.StaplerRequest2;
+
+/**
+ * Collect information about which URLs in {@code /extensionList/} are being accessed.
+ *
+ * @since TODO
+ */
+@Extension
+@Restricted(NoExternalUse.class)
+public class HttpExtensionList extends Telemetry {
+    private final Map<String, Integer> calls = new ConcurrentHashMap<>();
+
+    @NonNull
+    @Override
+    public String getDisplayName() {
+        return "Extension List access via HTTP";
+    }
+
+    @NonNull
+    @Override
+    public LocalDate getStart() {
+        return LocalDate.of(2025, 3, 18);
+    }
+
+    @NonNull
+    @Override
+    public LocalDate getEnd() {
+        return LocalDate.of(2025, 7, 1);
+    }
+
+    @Override
+    public synchronized JSONObject createContent() {
+        JSONObject info = new JSONObject();
+        info.put("components", buildComponentInformation());
+
+        Map<String, Integer> currentRequests = new TreeMap<>(calls);
+        calls.clear();
+
+        JSONObject payload = new JSONObject();
+        payload.putAll(currentRequests);
+
+        info.put("dispatches", payload);
+        return info;
+    }
+
+    public synchronized void record(String path) {
+        String[] parts = path.split("/");
+        if (parts.length > 1) {
+            // Record just extension point + implementation class
+            path = parts[0] + '/' + parts[1];
+        }
+        calls.compute(path, (p, v) -> v == null ? 1 : v + 1);
+    }
+
+    @Extension
+    @Restricted(NoExternalUse.class)
+    public static class ExtensionListRootAction extends InvisibleAction implements RootAction {
+        private static final Logger LOGGER = Logger.getLogger(ExtensionListRootAction.class.getName());
+
+        @Override
+        public String getUrlName() {
+            return "extensionList";
+        }
+
+        public ExtensionList getDynamic(String extensionType) throws ClassNotFoundException {
+            StaplerRequest2 req = Stapler.getCurrentRequest2();
+            if (req != null && extensionType != null) {
+                try {
+                    final HttpExtensionList telemetry = ExtensionList.lookupSingleton(HttpExtensionList.class);
+                    if (telemetry.isActivePeriod()) {
+                        telemetry.record(extensionType + req.getRestOfPath());
+                    }
+                } catch (Exception ex) {
+                    LOGGER.log(FINE, "Failed to record telemetry for " + HttpExtensionList.class.getName(), ex);
+                }
+            }
+            return Jenkins.get().getExtensionList(extensionType);
+        }
+    }
+}

core/src/main/resources/jenkins/telemetry/impl/HttpExtensionList/description.jelly

@@ -0,0 +1,9 @@
+<?jelly escape-by-default='true'?>
+<j:jelly xmlns:j="jelly:core">
+    <p>
+        ${%blurb}
+    </p>
+    <p>
+        ${%blurb2}
+    </p>
+</j:jelly>

core/src/main/resources/jenkins/telemetry/impl/HttpExtensionList/description.properties

@@ -0,0 +1,4 @@
+blurb = This trial records uses of an HTTP endpoint granting direct access to extensions, the building blocks of Jenkins's extensibility through plugins. \
+  It is expected that there are few legitimate uses of this endpoint, and this trial informs plans for its eventual removal.
+blurb2 = Additionally, this trial collects the list of installed plugins, their version, and the version of Jenkins. \
+  This data will be used to understand the environments that Jenkins is running in.

src/main/js/pages/manage-jenkins/system-information/index.js

@@ -10,7 +10,7 @@ graphHost.style.aspectRatio = `${imageWidth} / ${imageHeight}`;
 timespanSelect.addEventListener("change", () => {
   const rootURL = document.head.dataset.rooturl;
   const type = timespanSelect.value;
-  graphHost.innerHTML = `<img src="${rootURL}/extensionList/hudson.diagnosis.MemoryUsageMonitor/0/heap/graph?type=${type}&width=${imageWidth}&height=${imageHeight}" srcset="${rootURL}/extensionList/hudson.diagnosis.MemoryUsageMonitor/0/heap/graph?type=${type}&width=${imageWidth}&height=${imageHeight}&scale=2 2x" loading="lazy" style="width: 100%" alt="Memory usage graph"/>`;
+  graphHost.innerHTML = `<img src="${rootURL}/jenkins.diagnosis.MemoryUsageMonitorAction/heap/graph?type=${type}&width=${imageWidth}&height=${imageHeight}" srcset="${rootURL}/jenkins.diagnosis.MemoryUsageMonitorAction/heap/graph?type=${type}&width=${imageWidth}&height=${imageHeight}&scale=2 2x" loading="lazy" style="width: 100%" alt="Memory usage graph"/>`;
 });
 
 // Dispatch a change event to insert a graph on page load