[CCR] Rename leaderClient variables and parameters to remoteClient (#35368)

Author: martijnvg

x-pack/plugin/ccr/src/main/java/org/elasticsearch/xpack/ccr/CcrLicenseChecker.java

@@ -128,10 +128,10 @@ public void checkRemoteClusterLicenseAndFetchLeaderIndexMetadataAndHistoryUUIDs(
                         return;
                     }
 
-                    final Client leaderClient = client.getRemoteClusterClient(clusterAlias);
-                    hasPrivilegesToFollowIndices(leaderClient, new String[] {leaderIndex}, e -> {
+                    final Client remoteClient = client.getRemoteClusterClient(clusterAlias);
+                    hasPrivilegesToFollowIndices(remoteClient, new String[] {leaderIndex}, e -> {
                         if (e == null) {
-                            fetchLeaderHistoryUUIDs(leaderClient, leaderIndexMetaData, onFailure, historyUUIDs ->
+                            fetchLeaderHistoryUUIDs(remoteClient, leaderIndexMetaData, onFailure, historyUUIDs ->
                                     consumer.accept(historyUUIDs, leaderIndexMetaData));
                         } else {
                             onFailure.accept(e);
@@ -179,7 +179,7 @@ public void checkRemoteClusterLicenseAndFetchClusterState(
      *
      * @param client                     the client
      * @param clusterAlias               the remote cluster alias
-     * @param leaderClient               the leader client to use to execute cluster state API
+     * @param remoteClient               the remote client to use to execute cluster state API
      * @param request                    the cluster state request
      * @param onFailure                  the failure consumer
      * @param leaderClusterStateConsumer the leader cluster state consumer
@@ -189,7 +189,7 @@ public void checkRemoteClusterLicenseAndFetchClusterState(
     private void checkRemoteClusterLicenseAndFetchClusterState(
             final Client client,
             final String clusterAlias,
-            final Client leaderClient,
+            final Client remoteClient,
             final ClusterStateRequest request,
             final Consumer<Exception> onFailure,
             final Consumer<ClusterState> leaderClusterStateConsumer,
@@ -206,7 +206,7 @@ public void onResponse(final RemoteClusterLicenseChecker.LicenseCheck licenseChe
                             final ActionListener<ClusterStateResponse> clusterStateListener =
                                     ActionListener.wrap(s -> leaderClusterStateConsumer.accept(s.getState()), onFailure);
                             // following an index in remote cluster, so use remote client to fetch leader index metadata
-                            leaderClient.admin().cluster().state(request, clusterStateListener);
+                            remoteClient.admin().cluster().state(request, clusterStateListener);
                         } else {
                             onFailure.accept(nonCompliantLicense.apply(licenseCheck));
                         }
@@ -221,17 +221,17 @@ public void onFailure(final Exception e) {
     }
 
     /**
-     * Fetches the history UUIDs for leader index on per shard basis using the specified leaderClient.
+     * Fetches the history UUIDs for leader index on per shard basis using the specified remoteClient.
      *
-     * @param leaderClient                              the leader client
+     * @param remoteClient                              the remote client
      * @param leaderIndexMetaData                       the leader index metadata
      * @param onFailure                                 the failure consumer
      * @param historyUUIDConsumer                       the leader index history uuid and consumer
      */
     // NOTE: Placed this method here; in order to avoid duplication of logic for fetching history UUIDs
     // in case of following a local or a remote cluster.
     public void fetchLeaderHistoryUUIDs(
-        final Client leaderClient,
+        final Client remoteClient,
         final IndexMetaData leaderIndexMetaData,
         final Consumer<Exception> onFailure,
         final Consumer<String[]> historyUUIDConsumer) {
@@ -274,20 +274,20 @@ public void fetchLeaderHistoryUUIDs(
         IndicesStatsRequest request = new IndicesStatsRequest();
         request.clear();
         request.indices(leaderIndex);
-        leaderClient.admin().indices().stats(request, ActionListener.wrap(indicesStatsHandler, onFailure));
+        remoteClient.admin().indices().stats(request, ActionListener.wrap(indicesStatsHandler, onFailure));
     }
 
     /**
      * Check if the user executing the current action has privileges to follow the specified indices on the cluster specified by the leader
      * client. The specified callback will be invoked with null if the user has the necessary privileges to follow the specified indices,
      * otherwise the callback will be invoked with an exception outlining the authorization error.
      *
-     * @param leaderClient the leader client
+     * @param remoteClient the remote client
      * @param indices      the indices
      * @param handler      the callback
      */
-    public void hasPrivilegesToFollowIndices(final Client leaderClient, final String[] indices, final Consumer<Exception> handler) {
-        Objects.requireNonNull(leaderClient, "leaderClient");
+    public void hasPrivilegesToFollowIndices(final Client remoteClient, final String[] indices, final Consumer<Exception> handler) {
+        Objects.requireNonNull(remoteClient, "remoteClient");
         Objects.requireNonNull(indices, "indices");
         if (indices.length == 0) {
             throw new IllegalArgumentException("indices must not be empty");
@@ -298,7 +298,7 @@ public void hasPrivilegesToFollowIndices(final Client leaderClient, final String
             return;
         }
 
-        ThreadContext threadContext = leaderClient.threadPool().getThreadContext();
+        ThreadContext threadContext = remoteClient.threadPool().getThreadContext();
         SecurityContext securityContext = new SecurityContext(Settings.EMPTY, threadContext);
         String username = securityContext.getUser().principal();
 
@@ -332,7 +332,7 @@ public void hasPrivilegesToFollowIndices(final Client leaderClient, final String
                 handler.accept(Exceptions.authorizationError(message.toString()));
             }
         };
-        leaderClient.execute(HasPrivilegesAction.INSTANCE, request, ActionListener.wrap(responseHandler, handler));
+        remoteClient.execute(HasPrivilegesAction.INSTANCE, request, ActionListener.wrap(responseHandler, handler));
     }
 
     public static Client wrapClient(Client client, Map<String, String> headers) {

x-pack/plugin/ccr/src/main/java/org/elasticsearch/xpack/ccr/action/ShardFollowTasksExecutor.java

@@ -91,11 +91,11 @@ protected AllocatedPersistentTask createTask(long id, String type, String action
                                                  PersistentTasksCustomMetaData.PersistentTask<ShardFollowTask> taskInProgress,
                                                  Map<String, String> headers) {
         ShardFollowTask params = taskInProgress.getParams();
-        final Client leaderClient;
+        final Client remoteClient;
         if (params.getRemoteCluster() != null) {
-            leaderClient = wrapClient(client.getRemoteClusterClient(params.getRemoteCluster()), params.getHeaders());
+            remoteClient = wrapClient(client.getRemoteClusterClient(params.getRemoteCluster()), params.getHeaders());
         } else {
-            leaderClient = wrapClient(client, params.getHeaders());
+            remoteClient = wrapClient(client, params.getHeaders());
         }
         Client followerClient = wrapClient(client, params.getHeaders());
         BiConsumer<TimeValue, Runnable> scheduler = (delay, command) -> {
@@ -124,7 +124,7 @@ protected void innerUpdateMapping(LongConsumer handler, Consumer<Exception> erro
                 clusterStateRequest.metaData(true);
                 clusterStateRequest.indices(leaderIndex.getName());
 
-                leaderClient.admin().cluster().state(clusterStateRequest, ActionListener.wrap(clusterStateResponse -> {
+                remoteClient.admin().cluster().state(clusterStateRequest, ActionListener.wrap(clusterStateResponse -> {
                     IndexMetaData indexMetaData = clusterStateResponse.getState().metaData().getIndexSafe(leaderIndex);
                     if (indexMetaData.getMappings().isEmpty()) {
                         assert indexMetaData.getMappingVersion() == 1;
@@ -186,7 +186,7 @@ protected void innerUpdateSettings(final LongConsumer finalHandler, final Consum
                         }
                     }
                 };
-                leaderClient.admin().cluster().state(clusterStateRequest, ActionListener.wrap(onResponse, errorHandler));
+                remoteClient.admin().cluster().state(clusterStateRequest, ActionListener.wrap(onResponse, errorHandler));
             }
 
             private void closeIndexUpdateSettingsAndOpenIndex(String followIndex,
@@ -240,7 +240,7 @@ protected void innerSendShardChangesRequest(long from, int maxOperationCount, Co
                 request.setMaxOperationCount(maxOperationCount);
                 request.setMaxBatchSize(params.getMaxReadRequestSize());
                 request.setPollTimeout(params.getReadPollTimeout());
-                leaderClient.execute(ShardChangesAction.INSTANCE, request, ActionListener.wrap(handler::accept, errorHandler));
+                remoteClient.execute(ShardChangesAction.INSTANCE, request, ActionListener.wrap(handler::accept, errorHandler));
             }
         };
     }

x-pack/plugin/ccr/src/main/java/org/elasticsearch/xpack/ccr/action/TransportPutAutoFollowPatternAction.java

@@ -74,7 +74,7 @@ protected void masterOperation(PutAutoFollowPatternAction.Request request,
             listener.onFailure(LicenseUtils.newComplianceException("ccr"));
             return;
         }
-        final Client leaderClient = client.getRemoteClusterClient(request.getRemoteCluster());
+        final Client remoteClient = client.getRemoteClusterClient(request.getRemoteCluster());
         final ClusterStateRequest clusterStateRequest = new ClusterStateRequest();
         clusterStateRequest.clear();
         clusterStateRequest.metaData(true);
@@ -84,9 +84,9 @@ protected void masterOperation(PutAutoFollowPatternAction.Request request,
             .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
 
         String[] indices = request.getLeaderIndexPatterns().toArray(new String[0]);
-        ccrLicenseChecker.hasPrivilegesToFollowIndices(leaderClient, indices, e -> {
+        ccrLicenseChecker.hasPrivilegesToFollowIndices(remoteClient, indices, e -> {
             if (e == null) {
-                leaderClient.admin().cluster().state(
+                remoteClient.admin().cluster().state(
                     clusterStateRequest,
                     ActionListener.wrap(
                         clusterStateResponse -> {