Source/BladeX-Tool/blade-starter-loadbalancer/src/main/java/org/springblade/core/loadbalancer/rule/GrayscaleLoadBalancer.java

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/*
 *      Copyright (c) 2018-2028, Chill Zhuang All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 *
 *  Redistributions of source code must retain the above copyright notice,
 *  this list of conditions and the following disclaimer.
 *  Redistributions in binary form must reproduce the above copyright
 *  notice, this list of conditions and the following disclaimer in the
 *  documentation and/or other materials provided with the distribution.
 *  Neither the name of the dreamlu.net developer nor the names of its
 *  contributors may be used to endorse or promote products derived from
 *  this software without specific prior written permission.
 *  Author: Chill åº„骞 (smallchill@163.com)
 */
package org.springblade.core.loadbalancer.rule;

import com.alibaba.nacos.common.utils.StringUtils;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springblade.core.loadbalancer.props.BladeLoadBalancerProperties;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.*;
import org.springframework.cloud.loadbalancer.core.NoopServiceInstanceListSupplier;
import org.springframework.cloud.loadbalancer.core.ReactorServiceInstanceLoadBalancer;
import org.springframework.cloud.loadbalancer.core.ServiceInstanceListSupplier;
import org.springframework.http.HttpHeaders;
import org.springframework.util.CollectionUtils;
import org.springframework.util.PatternMatchUtils;
import reactor.core.publisher.Mono;

import java.util.List;
import java.util.concurrent.ThreadLocalRandom;
import java.util.stream.Collectors;

import static org.springblade.core.loadbalancer.constant.LoadBalancerConstant.VERSION_NAME;

/**
 * LoadBalancer è´Ÿè½½è§„则
 *
 * @author Chill
 */
@Slf4j
@RequiredArgsConstructor
public class GrayscaleLoadBalancer implements ReactorServiceInstanceLoadBalancer {
   private final ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider;
   private final BladeLoadBalancerProperties bladeLoadBalancerProperties;

   @Override
   public Mono<Response<ServiceInstance>> choose(Request request) {
      ServiceInstanceListSupplier supplier = serviceInstanceListSupplierProvider
         .getIfAvailable(NoopServiceInstanceListSupplier::new);
      return supplier.get(request).next()
         .map(serviceInstances -> getInstanceResponse(serviceInstances, request));
   }

   /**
    * è‡ªå®šä¹‰èŠ‚点规则返回目标节点
    */
   private Response<ServiceInstance> getInstanceResponse(List<ServiceInstance> instances, Request request) {
      // æ³¨å†Œä¸­å¿ƒæ— å¯ç”¨å®žä¾‹ è¿”回空
      if (CollectionUtils.isEmpty(instances)) {
         return new EmptyResponse();
      }
      // æŒ‡å®šip则返回满足ip的服务
      List<String> priorIpPattern = bladeLoadBalancerProperties.getPriorIpPattern();
      if (!priorIpPattern.isEmpty()) {
         String[] priorIpPatterns = priorIpPattern.toArray(new String[0]);
         List<ServiceInstance> priorIpInstances = instances.stream().filter(
            (i -> PatternMatchUtils.simpleMatch(priorIpPatterns, i.getHost()))
         ).collect(Collectors.toList());
         if (!priorIpInstances.isEmpty()) {
            instances = priorIpInstances;
         }
      }

      // èŽ·å–灰度版本号
      DefaultRequestContext context = (DefaultRequestContext) request.getContext();
      RequestData requestData = (RequestData) context.getClientRequest();
      HttpHeaders headers = requestData.getHeaders();
      String versionName = headers.getFirst(VERSION_NAME);

      // æ²¡æœ‰æŒ‡å®šç°åº¦ç‰ˆæœ¬åˆ™è¿”回正式的服务
      if (StringUtils.isBlank(versionName)) {
         List<ServiceInstance> noneGrayscaleInstances = instances.stream().filter(
            i -> !i.getMetadata().containsKey(VERSION_NAME)
         ).collect(Collectors.toList());
         return randomInstance(noneGrayscaleInstances);
      }

      // æŒ‡å®šç°åº¦ç‰ˆæœ¬åˆ™è¿”回标记的服务
      List<ServiceInstance> grayscaleInstances = instances.stream().filter(i -> {
         String versionNameInMetadata = i.getMetadata().get(VERSION_NAME);
         return StringUtils.equalsIgnoreCase(versionNameInMetadata, versionName);
      }).collect(Collectors.toList());
      return randomInstance(grayscaleInstances);
   }

   /**
    * é‡‡ç”¨éšæœºè§„则返回
    */
   private Response<ServiceInstance> randomInstance(List<ServiceInstance> instances) {
      // è‹¥æ²¡æœ‰å¯ç”¨èŠ‚点则返回空
      if (instances.isEmpty()) {
         return new EmptyResponse();
      }

      // æŒ‘选随机节点返回
      int randomIndex = ThreadLocalRandom.current().nextInt(instances.size());
      ServiceInstance instance = instances.get(randomIndex % instances.size());
      return new DefaultResponse(instance);
   }
}