jiajunwang commented on a change in pull request #1307: URL: https://github.com/apache/helix/pull/1307#discussion_r493051117
########## File path: helix-core/src/main/java/org/apache/helix/api/topology/ClusterTopology.java ########## @@ -0,0 +1,248 @@ +package org.apache.helix.api.topology; + +/* + * 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.ArrayDeque; +import java.util.ArrayList; +import java.util.Deque; +import java.util.HashMap; +import java.util.HashSet; +import java.util.LinkedHashMap; +import java.util.List; +import java.util.Map; +import java.util.Set; + +import org.apache.helix.model.ClusterConfig; +import org.apache.helix.model.ClusterTrie; +import org.apache.helix.model.InstanceConfig; +import org.apache.helix.model.TrieNode; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import static org.apache.helix.model.ClusterTrie.CONNECTOR; +import static org.apache.helix.model.ClusterTrie.DELIMITER; + + +public class ClusterTopology { + private static Logger logger = LoggerFactory.getLogger(ClusterTopology.class); + + private final ClusterTrie _trieClusterTopology; + + public ClusterTopology(final List<String> liveNodes, + final Map<String, InstanceConfig> instanceConfigMap, ClusterConfig clusterConfig) { + _trieClusterTopology = new ClusterTrie(liveNodes, instanceConfigMap, clusterConfig); + } + + /** + * Return the whole topology of a cluster as a map. The key of the map is the first level of + * domain, and the value is a list of string that represents the path to each end node in that + * domain. E.g., assume the topology is defined as /group/zone/rack/host, the result may be { + * ["/group:0": {"/zone:0/rack:0/host:0", "/zone:1/rack:1/host:1"}], ["/group:1": {"/zone:1 + * /rack:1/host:1", "/zone:1/rack:1/host:2"}]} + */ + public Map<String, List<String>> getTopologyMap() { + return getTopologyUnderDomain(new HashMap<>()); + } + + /** + * Return all the instances under fault zone type. The key of the returned map is each fault + * zone name, and the value is a list of string that represents the path to each end node in + * that fault zone. + * @return , e.g. if the fault zone is "zone", it may return {["/group:0/zone:0": {"rack:0/host + * :0", "rack:1/host:1"}, ["/group:0/zone:1": {"/rack:0:host:2", "/rack:1/host:3"}]} + */ + public Map<String, List<String>> getFaultZoneMap() { + String faultZone = _trieClusterTopology.getFaultZoneType(); + if (faultZone == null) { + throw new IllegalArgumentException("The fault zone in cluster config is not defined"); + } + return getTopologyUnderDomainType(faultZone); + } + + /** + * Return the instances whose domain field is not valid + */ + public List<String> getInvalidInstances() { + return _trieClusterTopology.getInvalidInstances(); + } + + /** + * Return the topology under a certain domain as a map. The key of the returned map is the next + * level domain, and the value is a list of string that represents the path to each end node in + * that domain. + * @param domain A map defining the domain name and its value, e.g. {["group": "1"], ["zone", + * "2"]} + * @return the topology under the given domain, e.g. {["/group:1/zone:2/rack:0": {"/host:0", + * "/host:1"}, ["/group:1/zone:2/rack:1": {"/host:2", "/host:3"}]} + */ + private Map<String, List<String>> getTopologyUnderDomain(Map<String, String> domain) { + LinkedHashMap<String, String> orderedDomain = validateAndOrderDomain(domain); + TrieNode startNode = getStartNode(orderedDomain); + Map<String, TrieNode> children = startNode.getChildren(); + Map<String, List<String>> results = new HashMap<>(); + children.entrySet().forEach(child -> { + results.put(startNode.getPath() + DELIMITER + child.getKey(), + truncatePath(getPathUnderNode(child.getValue()), child.getValue().getPath())); + }); + return results; + } + + /** + * Return the full topology of a certain domain type. + * @param domainType a specific type of domain, e.g. zone + * @return the topology of the given domain type, e.g. {["/group:0/zone:0": {"rack:0/host:0", + * "rack:1/host:1"}, ["/group:0/zone:1": {"/rack:0:host:2", "/rack:1/host:3"}]} + */ + private Map<String, List<String>> getTopologyUnderDomainType(String domainType) { + String[] topologyKeys = _trieClusterTopology.getTopologyKeys(); + if (domainType.equals(topologyKeys[0])) { + return getTopologyMap(); + } + Map<String, List<String>> results = new HashMap<>(); + String parentDomainType = null; + for (int i = 1; i < topologyKeys.length; i++) { + if (topologyKeys[i].equals(domainType)) { + parentDomainType = topologyKeys[i - 1]; + break; + } + } + // get all the starting nodes for the domain type + List<TrieNode> startNodes = getStartNodes(parentDomainType); + for (TrieNode startNode : startNodes) { + results.putAll(getTopologyUnderPath(startNode.getPath())); + } + return results; + } + + /** + * Return the topology under a certain path as a map. The key of the returned map is the next + * level domain, and the value is a list of string that represents the path to each end node in + * that domain. + * @param path a path to a certain Trie node, e.g. /group:1/zone:2 + * @return the topology under the given domain, e.g. {["/group:1/zone:2/rack:0": {"/host:0", + * "/host:1"}, ["/group:1/zone:2/rack:1": {"/host:2", "/host:3"}]} + */ + private Map<String, List<String>> getTopologyUnderPath(String path) { + Map<String, String> domain = convertPathToDomain(path); + return getTopologyUnderDomain(domain); + } + + /** + * Validate the domain provided has continuous fields in cluster topology definition. If it + * has, order the domain based on cluster topology definition. E.g. if the cluster topology is + * /group/zone/rack/instance, and domain is provided as {["zone": "1"], ["group", "2"]} will be + * reordered in a LinkedinHashMap as {["group", "2"], ["zone": "1"]} + */ + private LinkedHashMap<String, String> validateAndOrderDomain(Map<String, String> domain) { + LinkedHashMap<String, String> orderedDomain = new LinkedHashMap<>(); + if (domain == null) { + throw new IllegalArgumentException("The domain should not be null"); + } + String[] topologyKeys = _trieClusterTopology.getTopologyKeys(); + for (int i = 0; i < domain.size(); i++) { + if (!domain.containsKey(topologyKeys[i])) { + throw new IllegalArgumentException(String + .format("The input domain is not valid, the key %s is required", topologyKeys[i])); + } else { + orderedDomain.put(topologyKeys[i], domain.get(topologyKeys[i])); + } + } + return orderedDomain; + } + + /** + * Truncate each path in the given set and only retain path starting from current node's + * children to each end node. + * @param toRemovePath The path from root to current node. It should be removed so that users + * can get a better view. + */ + private List<String> truncatePath(Set<String> paths, String toRemovePath) { + List<String> results = new ArrayList<>(); + paths.forEach(path -> { + String truncatedPath = path.replace(toRemovePath, ""); + results.add(truncatedPath); + }); + return results; + } + + /** + * Return all the paths from a TrieNode as a set. + * @param node the node from where to collect all the nodes' paths. + * @return All the paths under the node. + */ + private Set<String> getPathUnderNode(TrieNode node) { + Set<String> resultMap = new HashSet<>(); + Deque<TrieNode> nodeStack = new ArrayDeque<>(); + nodeStack.push(node); + while (!nodeStack.isEmpty()) { + node = nodeStack.pop(); + if (node.getChildren().isEmpty()) { + resultMap.add(node.getPath()); + } else { + for (TrieNode child : node.getChildren().values()) { + nodeStack.push(child); + } + } + } + return resultMap; + } + + private TrieNode getStartNode(LinkedHashMap<String, String> domain) { Review comment: I understand the logic, I'm just asking about the name. Since this method can also be used to get the leaf, I feel getNode() is simpler and more generic. But no strong preference here. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
