[GitHub] [helix] xyuanlu commented on a change in pull request #1935: Implement java API and utils for virtual topology group

[GitBox <gi...@apache.org>]

xyuanlu commented on a change in pull request #1935:
URL: https://github.com/apache/helix/pull/1935#discussion_r785253766



##########
File path: helix-rest/src/main/java/org/apache/helix/rest/server/service/VirtualTopologyGroupService.java
##########
@@ -0,0 +1,163 @@
+package org.apache.helix.rest.server.service;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Preconditions;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import org.apache.commons.lang3.StringUtils;
+import org.apache.helix.AccessOption;
+import org.apache.helix.ConfigAccessor;
+import org.apache.helix.HelixAdmin;
+import org.apache.helix.HelixDataAccessor;
+import org.apache.helix.HelixException;
+import org.apache.helix.common.VirtualTopologyGroupConstants;
+import org.apache.helix.controller.VirtualTopologyGroupStrategy;
+import org.apache.helix.model.CloudConfig;
+import org.apache.helix.model.ClusterConfig;
+import org.apache.helix.model.HelixConfigScope;
+import org.apache.helix.model.InstanceConfig;
+import org.apache.helix.model.builder.HelixConfigScopeBuilder;
+import org.apache.helix.rest.server.json.cluster.ClusterTopology;
+import org.apache.helix.zookeeper.datamodel.ZNRecord;
+import org.apache.helix.zookeeper.zkclient.DataUpdater;
+
+
+/**
+ * Service for virtual topology group.
+ */
+public class VirtualTopologyGroupService {
+  private final HelixAdmin _helixAdmin;
+  private final ClusterService _clusterService;
+  private final ConfigAccessor _configAccessor;
+  private final HelixDataAccessor _dataAccessor;
+  private final VirtualTopologyGroupStrategy _strategy;
+
+  public VirtualTopologyGroupService(HelixAdmin helixAdmin, ClusterService clusterService,
+      ConfigAccessor configAccessor, HelixDataAccessor dataAccessor) {
+    _helixAdmin = helixAdmin;
+    _clusterService = clusterService;
+    _configAccessor = configAccessor;
+    _dataAccessor = dataAccessor;
+    _strategy = VirtualTopologyGroupStrategy.DEFAULT;
+  }
+
+  /**
+   * Add virtual topology group for a cluster.
+   * This includes calculating the virtual group assignment for all instances in the cluster then update instance config
+   * and cluster config. Cluster is expected to enter maintenanceMode during config update, this is either enabled/disabled
+   * in place this method or handled by client side code.
+   * @param clusterName the cluster name.
+   * @param customFields custom fields, {@link VirtualTopologyGroupConstants#GROUP_NAME}
+   *                     and {@link VirtualTopologyGroupConstants#GROUP_NUMBER} are required
+   * @param enterMaintenanceMode if enabled, the cluster will enter maintenance mode during the setup and exit once it
+   *                             completes. Otherwise, it's expected the maintenanceMode is controlled by client side.
+   */
+  public void addVirtualTopologyGroup(String clusterName, Map<String, String> customFields, boolean enterMaintenanceMode) {
+    // only support if CLOUD_ENABLED AND VIRTUAL_GROUP_ENABLED
+    CloudConfig cloudConfig = _configAccessor.getCloudConfig(clusterName);
+    if (cloudConfig == null || !cloudConfig.isCloudEnabled()) {
+      throw new HelixException(
+          "Cloud is not enabled, addVirtualTopologyGroup is not allowed to run in non-cloud environment.");
+    }
+    ClusterConfig clusterConfig = _configAccessor.getClusterConfig(clusterName);
+    if (!clusterConfig.isVirtualGroupEnabled()) {
+      throw new HelixException("Virtual Group is disabled in cluster " + clusterName);
+    }
+    // validation
+    String groupName = customFields.get(VirtualTopologyGroupConstants.GROUP_NAME);
+    String groupNumberStr = Preconditions.checkNotNull(
+        customFields.get(VirtualTopologyGroupConstants.GROUP_NUMBER),
+        "virtualTopologyGroupNumber cannot be empty!");
+    Preconditions.checkState(!StringUtils.isEmpty(groupName), "virtualTopologyGroupName cannot be empty!");
+    int numGroups = Integer.parseInt(groupNumberStr);
+
+    // compute group assignment
+    ClusterTopology clusterTopology = _clusterService.getClusterTopology(clusterName);
+    Map<String, Set<String>> assignment =
+        _strategy.computeAssignment(numGroups, groupName, clusterTopology.toZoneMapping());
+
+    if (enterMaintenanceMode) {
+      _helixAdmin.manuallyEnableMaintenanceMode(clusterName, true,
+          "Enable maintenanceMode for virtual topology group change.", customFields);
+    }
+    Preconditions.checkState(_helixAdmin.isInMaintenanceMode(clusterName),
+        "Cluster is not in maintenance mode. This is required for virtual topology group setting. "
+            + "Please enable enterMaintenanceMode or enter maintenance mode for the cluster prior to the API call.");
+
+    updateConfigs(clusterName, clusterConfig, assignment);
+    if (enterMaintenanceMode) {
+      _helixAdmin.manuallyEnableMaintenanceMode(clusterName, false,
+          "Disable maintenanceMode after virtual topology group change.", customFields);
+    }
+  }
+
+  private void updateConfigs(String clusterName, ClusterConfig clusterConfig, Map<String, Set<String>> assignment) {
+    List<String> zkPaths = new ArrayList<>();
+    List<DataUpdater<ZNRecord>> updaters = new ArrayList<>();
+    createInstanceConfigUpdater(clusterName, assignment).forEach((zkPath, updater) -> {
+      zkPaths.add(zkPath);
+      updaters.add(updater);
+    });
+    boolean[] results = _dataAccessor.updateChildren(zkPaths, updaters, AccessOption.EPHEMERAL);
+    for (int i = 0; i < results.length; i++) {

Review comment:
       nit: how about 
   if ( results.stream().anyMatch(res-> !res) ) {
      throw new HelixException("Failed to update instance config for path " + zkPaths.get(i));
   }




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