CPS SPI POC

Author: n1v0lg

server/src/main/java/module-info.java

@@ -398,7 +398,8 @@
             org.elasticsearch.settings.secure,
             org.elasticsearch.serverless.constants,
             org.elasticsearch.serverless.apifiltering,
-            org.elasticsearch.internal.security;
+            org.elasticsearch.internal.security,
+            org.elasticsearch.serverless.crossproject;
 
     exports org.elasticsearch.telemetry.tracing;
     exports org.elasticsearch.telemetry;

server/src/main/java/org/elasticsearch/action/search/CrossClusterSearchExtension.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+package org.elasticsearch.action.search;
+
+public interface CrossClusterSearchExtension {
+
+    boolean forceReconnect();
+
+    class Noop implements CrossClusterSearchExtension {
+        public Noop() {}
+
+        @Override
+        public boolean forceReconnect() {
+            return false;
+        }
+    }
+}

server/src/main/java/org/elasticsearch/node/NodeConstruction.java

@@ -23,6 +23,7 @@
 import org.elasticsearch.action.bulk.IncrementalBulkService;
 import org.elasticsearch.action.datastreams.autosharding.DataStreamAutoShardingService;
 import org.elasticsearch.action.ingest.ReservedPipelineAction;
+import org.elasticsearch.action.search.CrossClusterSearchExtension;
 import org.elasticsearch.action.search.OnlinePrewarmingService;
 import org.elasticsearch.action.search.OnlinePrewarmingServiceProvider;
 import org.elasticsearch.action.search.SearchExecutionStatsCollector;
@@ -1015,6 +1016,14 @@ public Map<String, String> queryFields() {
 
         var reservedStateHandlerProviders = pluginsService.loadServiceProviders(ReservedStateHandlerProvider.class);
 
+        var crossClusterSearchExtension = pluginsService.loadSingletonServiceProvider(
+            CrossClusterSearchExtension.class,
+            CrossClusterSearchExtension.Noop::new
+        );
+
+        logger.info("Using cross-cluster search extension: [{}]", crossClusterSearchExtension.getClass().getName());
+        logger.info("Cross-cluster search force reconnect: [{}]", crossClusterSearchExtension.forceReconnect());
+
         ActionModule actionModule = new ActionModule(
             settings,
             clusterModule.getIndexNameExpressionResolver(),