| /** |
| * 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. |
| * |
| */ |
| public interface DNSToSwitchMapping { |
| public final static 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. |
| * |
| * 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 |
| */ |
| public Map<String, String> resolve(List<String> names); |
| } |