Invalidate service user cache each time All-Projects is updated

To make sure that the cache is fresh on all Gerrit instances
in a multi-site setup.

Bug: Issue 372736304
Change-Id: I20a177ab18b9efb46e9f92014721553103b75d37

src/main/java/com/googlesource/gerrit/plugins/serviceuser/CacheInvalidator.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/CacheInvalidator.java b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/CacheInvalidator.java
new file mode 100644
index 0000000..fbf1eac
--- /dev/null
+++ b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/CacheInvalidator.java
@@ -0,0 +1,51 @@
+// Copyright (C) 2024 The Android Open Source Project
+//
+// 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.googlesource.gerrit.plugins.serviceuser;
+
+import com.google.common.flogger.FluentLogger;
+import com.google.gerrit.entities.RefNames;
+import com.google.gerrit.server.config.AllProjectsName;
+import com.google.gerrit.server.events.Event;
+import com.google.gerrit.server.events.EventListener;
+import com.google.gerrit.server.events.RefUpdatedEvent;
+import com.google.inject.Inject;
+
+class CacheInvalidator implements EventListener {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+  private final AllProjectsName allProjects;
+  private final StorageCache storageCache;
+
+  @Inject
+  CacheInvalidator(AllProjectsName allProjects, StorageCache storageCache) {
+    this.allProjects = allProjects;
+    this.storageCache = storageCache;
+  }
+
+  @Override
+  public void onEvent(Event event) {
+    // This is needed in a multi-site setup to make sure every Gerrit instance
+    // has the latest created serviceuser in cache.
+    if (event.getType().equals(RefUpdatedEvent.TYPE)) {
+      RefUpdatedEvent refUpdatedEvent = (RefUpdatedEvent) event;
+      if (refUpdatedEvent.getProjectNameKey().get().equals(allProjects.get())
+          && refUpdatedEvent.getRefName().equals(RefNames.REFS_CONFIG)) {
+        logger.atFine().log(
+            "%s ref update triggered, invalidate serviceuser cache", allProjects.get());
+        storageCache.invalidate();
+      }
+    }
+  }
+}

src/main/java/com/googlesource/gerrit/plugins/serviceuser/Module.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/Module.java b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/Module.java
index 5b5df2f..39d5788 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/Module.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/Module.java
@@ -26,6 +26,7 @@
 import com.google.gerrit.extensions.registration.DynamicSet;
 import com.google.gerrit.extensions.restapi.RestApiModule;
 import com.google.gerrit.extensions.webui.TopMenu;
+import com.google.gerrit.server.events.EventListener;
 import com.google.gerrit.server.git.validators.CommitValidationListener;
 import com.google.gerrit.server.project.ProjectLevelConfig;
 import com.google.inject.AbstractModule;
@@ -42,6 +43,7 @@
     DynamicSet.bind(binder(), TopMenu.class).to(ServiceUserTopMenu.class);
     DynamicSet.bind(binder(), GitReferenceUpdatedListener.class).to(RefUpdateListener.class);
     DynamicSet.bind(binder(), CommitValidationListener.class).to(ValidateServiceUserCommits.class);
+    DynamicSet.bind(binder(), EventListener.class).to(CacheInvalidator.class);
     install(new FactoryModuleBuilder().build(CreateServiceUserNotes.Factory.class));
     install(
         new RestApiModule() {