Add cluster.remote.connect to deprecation info API (#54142)

This setting was recently deprecated in favor of
node.remote_cluster_client. This commit adds this setting to the
deprecation info API.

Author: jasontedor

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/DeprecationChecks.java

@@ -47,7 +47,8 @@ private DeprecationChecks() {
             NodeDeprecationChecks::checkMissingRealmOrders,
             NodeDeprecationChecks::checkUniqueRealmOrders,
             (settings, pluginsAndModules) -> NodeDeprecationChecks.checkThreadPoolListenerQueueSize(settings),
-            (settings, pluginsAndModules) -> NodeDeprecationChecks.checkThreadPoolListenerSize(settings)
+            (settings, pluginsAndModules) -> NodeDeprecationChecks.checkThreadPoolListenerSize(settings),
+            NodeDeprecationChecks::checkClusterRemoteConnectSetting
         ));
 
     static List<Function<IndexMetaData, DeprecationIssue>> INDEX_SETTINGS_CHECKS =

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/NodeDeprecationChecks.java

@@ -11,7 +11,9 @@
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.util.concurrent.EsExecutors;
 import org.elasticsearch.env.Environment;
+import org.elasticsearch.node.Node;
 import org.elasticsearch.threadpool.FixedExecutorBuilder;
+import org.elasticsearch.transport.RemoteClusterService;
 import org.elasticsearch.xpack.core.deprecation.DeprecationIssue;
 import org.elasticsearch.xpack.core.security.authc.RealmSettings;
 
@@ -117,6 +119,16 @@ private static DeprecationIssue checkThreadPoolListenerSetting(final String name
             "https://www.elastic.co/guide/en/elasticsearch/reference/7.x/breaking-changes-7.7.html#deprecate-listener-thread-pool");
     }
 
+    public static DeprecationIssue checkClusterRemoteConnectSetting(final Settings settings, final PluginsAndModules pluginsAndModules) {
+        return checkDeprecatedSetting(
+            settings,
+            pluginsAndModules,
+            RemoteClusterService.ENABLE_REMOTE_CLUSTERS,
+            Node.NODE_REMOTE_CLUSTER_CLIENT,
+            "https://www.elastic.co/guide/en/elasticsearch/reference/7.7/breaking-changes-7.7.html#deprecate-cluster-remote-connect"
+        );
+    }
+
     private static DeprecationIssue checkDeprecatedSetting(
         final Settings settings,
         final PluginsAndModules pluginsAndModules,

x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/NodeDeprecationChecksTests.java

@@ -11,7 +11,9 @@
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.util.concurrent.EsExecutors;
 import org.elasticsearch.env.Environment;
+import org.elasticsearch.node.Node;
 import org.elasticsearch.test.ESTestCase;
+import org.elasticsearch.transport.RemoteClusterService;
 import org.elasticsearch.xpack.core.deprecation.DeprecationIssue;
 import org.elasticsearch.xpack.core.security.authc.RealmConfig;
 import org.elasticsearch.xpack.core.security.authc.RealmSettings;
@@ -176,6 +178,27 @@ public void testThreadPoolListenerSize() {
         assertSettingDeprecationsAndWarnings(new String[]{"thread_pool.listener.size"});
     }
 
+    public void testClusterRemoteConnectSetting() {
+        final boolean value = randomBoolean();
+        final Settings settings = Settings.builder().put(RemoteClusterService.ENABLE_REMOTE_CLUSTERS.getKey(), value).build();
+        final PluginsAndModules pluginsAndModules = new PluginsAndModules(Collections.emptyList(), Collections.emptyList());
+        final List<DeprecationIssue> issues =
+            DeprecationChecks.filterChecks(DeprecationChecks.NODE_SETTINGS_CHECKS, c -> c.apply(settings, pluginsAndModules));
+        final DeprecationIssue expected = new DeprecationIssue(
+            DeprecationIssue.Level.CRITICAL,
+            "setting [cluster.remote.connect] is deprecated in favor of setting [node.remote_cluster_client]",
+            "https://www.elastic.co/guide/en/elasticsearch/reference/7.7/breaking-changes-7.7.html#deprecate-cluster-remote-connect",
+            String.format(
+                Locale.ROOT,
+                "the setting [%s] is currently set to [%b], instead set [%s] to [%2$b]",
+                RemoteClusterService.ENABLE_REMOTE_CLUSTERS.getKey(),
+                value,
+                Node.NODE_REMOTE_CLUSTER_CLIENT.getKey()
+            ));
+        assertThat(issues, contains(expected));
+        assertSettingDeprecationsAndWarnings(new Setting<?>[]{RemoteClusterService.ENABLE_REMOTE_CLUSTERS});
+    }
+
     public void testRemovedSettingNotSet() {
         final Settings settings = Settings.EMPTY;
         final Setting<?> removedSetting = Setting.simpleString("node.removed_setting");