001/**
002 * Copyright (c) 2015-2022, Michael Yang 杨福海 (fuhai999@gmail.com).
003 * <p>
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 * <p>
008 * http://www.apache.org/licenses/LICENSE-2.0
009 * <p>
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package io.jboot.components.gateway;
017
018import javax.servlet.http.HttpServletRequest;
019import java.util.concurrent.ThreadLocalRandom;
020
021/**
022 * 负载均衡策略
023 */
024public interface GatewayLoadBalanceStrategy {
025
026    /**
027     * 默认的负载均衡策略，随机返回一个 url
028     */
029    GatewayLoadBalanceStrategy DEFAULT_STRATEGY = (config, request) -> {
030        String[] urls = config.getHealthUris();
031        if (urls == null || urls.length == 0) {
032            return null;
033        } else if (urls.length == 1) {
034            return urls[0];
035        } else {
036            return urls[ThreadLocalRandom.current().nextInt(urls.length)];
037        }
038    };
039
040    String getUrl(JbootGatewayConfig config, HttpServletRequest request);
041}