| /** |
| * 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 |
| * <p> |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * <p> |
| * 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. |
| */ |
| |
| package org.apache.storm.networktopography; |
| |
| import java.util.List; |
| import java.util.Map; |
| |
| /** |
| * An interface that must be implemented to allow pluggable DNS-name/IP-address to RackID resolvers. |
| */ |
| @SuppressWarnings("checkstyle:AbbreviationAsWordInName") |
| public interface DNSToSwitchMapping { |
| String DEFAULT_RACK = "/default-rack"; |
| |
| /** |
| * Resolves a list of DNS-names/IP-address and returns back a map of DNS-name->switch information ( network paths). |
| * Consider an element in the argument list - x.y.com. The switch information that is returned must be a network |
| * path of the form /foo/rack, where / is the root, and 'foo' is the switch where 'rack' is connected. Note the |
| * hostname/ip-address is not part of the returned path. The network topology of the cluster would determine the |
| * number of components in the network path. |
| * |
| * <p>If a name cannot be resolved to a rack, the implementation should return {DEFAULT_RACK}. This is what the |
| * bundled implementations do, though it is not a formal requirement. |
| * |
| * @param names the list of hosts to resolve (can be empty) |
| * @return Map of hosts to resolved network paths. If <i>names</i> is empty, then return empty Map |
| */ |
| Map<String, String> resolve(List<String> names); |
| } |