| package org.apache.helix.controller; |
| |
| /* |
| * 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 java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Set; |
| import java.util.TreeMap; |
| import java.util.TreeSet; |
| |
| import org.apache.helix.ZNRecord; |
| import org.apache.helix.model.CurrentState.CurrentStateProperty; |
| import org.apache.helix.model.Message; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /* |
| * ZKRoutingInfoProvider keeps a copy of the routing table. Given a partition id, |
| * it will return |
| * |
| * 1. The list of partition that can be read |
| * 2. the master partition, for write operation |
| * |
| * The routing table is constructed from the currentState of each storage nodes. |
| * The current state is a list of following pairs: partition-id:State(MASTER / SLAVE) |
| * |
| * TODO: move the code as part of router process |
| * TODO: add listeners to node current state changes |
| * */ |
| public class ExternalViewGenerator { |
| static Logger _logger = LoggerFactory.getLogger(ExternalViewGenerator.class); |
| |
| /* |
| * Given a list of external view ZNRecord nodes(one for each cluster), |
| * calculate the routing map. |
| * The format of the routing map is like this: |
| * Map<String, Map<String, Set<String>>> maps from a partitionName to its |
| * states Map<String, List<String>> The second Map maps from a state |
| * ("MASTER", "SLAVE"...) to a list of nodeNames |
| * So that the we can query the map for the list of nodes by providing the |
| * partition name and the expected state. |
| */ |
| public Map<String, Map<String, Set<String>>> getRouterMapFromExternalView( |
| List<ZNRecord> externalViewList) { |
| Map<String, Map<String, Set<String>>> result = new TreeMap<String, Map<String, Set<String>>>(); |
| |
| for (ZNRecord nodeView : externalViewList) { |
| Map<String, Map<String, String>> partitionNodeStateMap = nodeView.getMapFields(); |
| for (String partitionId : partitionNodeStateMap.keySet()) { |
| if (!result.containsKey(partitionId)) { |
| result.put(partitionId, new TreeMap<String, Set<String>>()); |
| } |
| Map<String, String> nodeStateMap = partitionNodeStateMap.get(partitionId); |
| for (String nodeName : nodeStateMap.keySet()) { |
| String state = nodeStateMap.get(nodeName); |
| if (!result.get(partitionId).containsKey(state)) { |
| result.get(partitionId).put(state, new TreeSet<String>()); |
| } |
| result.get(partitionId).get(state).add(nodeName); |
| } |
| } |
| } |
| return result; |
| } |
| |
| /* |
| * The parameter is a map that maps the nodeName to a list of ZNRecords. |
| */ |
| public List<ZNRecord> computeExternalView(Map<String, List<ZNRecord>> currentStates, |
| List<ZNRecord> idealStates) { |
| List<ZNRecord> resultList = new ArrayList<ZNRecord>(); |
| Map<String, ZNRecord> resultRoutingTable = new HashMap<String, ZNRecord>(); |
| // maps from resourceName to another map : partition -> map <nodename, |
| // master/slave>; |
| // Fill the routing table with "empty" default state according to ideals |
| // states |
| // in the cluster |
| if (idealStates != null) { |
| for (ZNRecord idealState : idealStates) { |
| ZNRecord defaultExternalView = new ZNRecord(idealState.getId()); |
| resultRoutingTable.put(idealState.getId(), defaultExternalView); |
| } |
| } else { |
| assert (!currentStates.isEmpty()); |
| return resultList; |
| } |
| for (String nodeName : currentStates.keySet()) { |
| List<ZNRecord> znStates = currentStates.get(nodeName); |
| for (ZNRecord nodeStateRecord : znStates) { |
| Map<String, Map<String, String>> resourceStates = nodeStateRecord.getMapFields(); |
| for (String stateUnitKey : resourceStates.keySet()) { |
| Map<String, String> partitionStates = resourceStates.get(stateUnitKey); |
| String resourceName = partitionStates.get(Message.Attributes.RESOURCE_NAME.toString()); |
| ZNRecord partitionStatus = resultRoutingTable.get(resourceName); |
| if (partitionStatus == null) { |
| partitionStatus = new ZNRecord(resourceName); |
| resultRoutingTable.put(resourceName, partitionStatus); |
| } |
| String currentStateKey = CurrentStateProperty.CURRENT_STATE.name(); |
| |
| if (!partitionStatus.getMapFields().containsKey(stateUnitKey)) { |
| partitionStatus.setMapField(stateUnitKey, new TreeMap<String, String>()); |
| } |
| partitionStatus.getMapField(stateUnitKey).put(nodeName, |
| partitionStates.get(currentStateKey)); |
| |
| } |
| } |
| } |
| for (ZNRecord record : resultRoutingTable.values()) { |
| resultList.add(record); |
| } |
| return resultList; |
| } |
| } |