【Soul源码阅读-02】devide插件负载均衡权重分析

时间 2021-01-20

标签 java spring bootstrap 设计模式缓存 mvc app 负载均衡 dom ide 栏目负载均衡繁體版

原文原文链接

目标

运行 examples下面的 http 服务
学习文档，结合 divde 插件，发起 http 请求 soul 网关，体验 http 代理

http 服务的相关依赖及配置

引入 http 的代理插件

在 soul-bootstrap 工程下的 pom.xml下引入以下依赖java

<!--if you use http proxy start this-->
 <dependency>
     <groupId>org.dromara</groupId>
     <artifactId>soul-spring-boot-starter-plugin-divide</artifactId>
     <version>${project.version}</version>
 </dependency>
 <dependency>
     <groupId>org.dromara</groupId>
     <artifactId>soul-spring-boot-starter-plugin-httpclient</artifactId>
     <version>${project.version}</version>
 </dependency>

引入 soul 客户端（针对SpringBoot用户）：

在 soul-examples-http(你本身的真实服务) pom.xml 新增以下依赖:spring

<dependency>
         <groupId>org.dromara</groupId>
         <artifactId>soul-spring-boot-starter-client-springmvc</artifactId>
         <version>${last.version}</version>
     </dependency>

添加客户端接入配置：

在yml中新增以下配置：bootstrap

soul:
  http:
    adminUrl: http://localhost:9095
    port: 8188
    contextPath: /myhttp
    appName: http
    full: false
    
   # adminUrl: 为你启动的 soul-admin 项目的ip + 端口，注意要加http://
   # port: 你本项目的启动端口
   # contextPath: 为你的这个mvc项目在soul网关的路由前缀，好比/order ，/product 等等，网关会根据你的这个前缀来进行路由
   # appName：你的应用名称，不配置的话，会默认取 `spring.application.name` 的值
   # full: 设置true 表明代理你的整个服务，false表示代理你其中某几个controller

Controller中添加@SoulSpringMvcClient注解

将注解 Controller 类上面，里面的path属性则为前缀，若是含有 /** 表明你的整个接口须要被网关代理。设计模式

@RestController
@RequestMapping("/test")
@SoulSpringMvcClient(path = "/test/**")
public class HttpTestController {
  //controller中全部方法被网关代理
}

@RestController
@RequestMapping("/order")
@SoulSpringMvcClient(path = "/order")
public class OrderController {
    /**
      * order/save会被网关代理,而/order/findById 则不会
      */
    @PostMapping("/save")
    @SoulSpringMvcClient(path = "/save" , desc = "Save order")
    public OrderDTO save(@RequestBody final OrderDTO orderDTO) {
        orderDTO.setName("hello world save order");
        return orderDTO;
    }

    @GetMapping("/findById")
    public OrderDTO findById(@RequestParam("id") final String id) {
        OrderDTO orderDTO = new OrderDTO();
        orderDTO.setId(id);
        orderDTO.setName("hello world findById");
        return orderDTO;
    }
}

devide 负载均衡权重分析

修改 diea 启动配置，勾选Allow parallel run，容许并行启动缓存

修改application.yml中端口配置，将端口改成8189mvc

server:
  port: 8189 # 修改端口
  address: 0.0.0.0

soul:
  http:
    adminUrl: http://localhost:9095
    port: 8189 # 修改端口
    contextPath: /http
    appName: http
    full: false

成功启动，soul 后台中会新注册一个 8189 服务app

修改weight权重配置，将8188权重改成100负载均衡

采用假设性原则，根据工程名及文件名称，在DividePlugin.java的doExecute方法中添加断点。使用 Postman 对网关发起一个请求，遇到断点，查看调用栈信息dom

一直往上找，发现请求会先进入SoulWebHandler 类的 handle 方法里：ide

@Override
    public Mono<Void> handle(@NonNull final ServerWebExchange exchange) {
        MetricsTrackerFacade.getInstance().counterInc(MetricsLabelEnum.REQUEST_TOTAL.getName());
        Optional<HistogramMetricsTrackerDelegate> startTimer = MetricsTrackerFacade.getInstance().histogramStartTimer(MetricsLabelEnum.REQUEST_LATENCY.getName());
        return new DefaultSoulPluginChain(plugins).execute(exchange).subscribeOn(scheduler)
                .doOnSuccess(t -> startTimer.ifPresent(time -> MetricsTrackerFacade.getInstance().histogramObserveDuration(time)));
    }

而后调用 DefaultSoulPluginChain 的 execute 方法，从 plugins 中获取DividePlugin插件：

public Mono<Void> execute(final ServerWebExchange exchange) {
            return Mono.defer(() -> {
                if (this.index < plugins.size()) {
                    //获取插件
                    SoulPlugin plugin = plugins.get(this.index++);
                    Boolean skip = plugin.skip(exchange);
                    if (skip) {
                        //跳过插件
                        return this.execute(exchange);
                    }
                    //调用插件的具体执行方法
                    return plugin.execute(exchange, this);
                }
                return Mono.empty();
            });
        }

调用了插件的具体执行方法后，进入AbstractSoulPlugin 类的 execute 方法，这里使用了模板方法设计模式，会匹配每个插件，直到找到divide插件

public Mono<Void> execute(final ServerWebExchange exchange, final SoulPluginChain chain) {
        //获取插件名称
        String pluginName = named();
        //从缓存中获取插件信息
        final PluginData pluginData = BaseDataCache.getInstance().obtainPluginData(pluginName);
        if (pluginData != null && pluginData.getEnabled()) {
             // 从缓存中根据插件名称获取对应选择器列表
            final Collection<SelectorData> selectors = BaseDataCache.getInstance().obtainSelectorData(pluginName);
            if (CollectionUtils.isEmpty(selectors)) {
                return handleSelectorIsNull(pluginName, exchange, chain);
            }
             // 匹配选择器
            final SelectorData selectorData = matchSelector(exchange, selectors);
            if (Objects.isNull(selectorData)) {
                return handleSelectorIsNull(pluginName, exchange, chain);
            }
            selectorLog(selectorData, pluginName);
            //从缓存中获取选择器对应的规则列表
            final List<RuleData> rules = BaseDataCache.getInstance().obtainRuleData(selectorData.getId());
            if (CollectionUtils.isEmpty(rules)) {
                return handleRuleIsNull(pluginName, exchange, chain);
            }
            RuleData rule;
            //不太明白
            if (selectorData.getType() == SelectorTypeEnum.FULL_FLOW.getCode()) {
                //get last
                rule = rules.get(rules.size() - 1);
            } else {
                rule = matchRule(exchange, rules);
            }
            if (Objects.isNull(rule)) {
                return handleRuleIsNull(pluginName, exchange, chain);
            }
            ruleLog(rule, pluginName);
            //调用具体执行方法
            return doExecute(exchange, chain, selectorData, rule);
        }
        return chain.execute(exchange);
    }

而后就回到了最初的起点，在DividePlugin.java的doExecute方法中打的第一个断点

protected Mono<Void> doExecute(final ServerWebExchange exchange, final SoulPluginChain chain, final SelectorData selector, final RuleData rule) {
        final SoulContext soulContext = exchange.getAttribute(Constants.CONTEXT);
        assert soulContext != null;
        final DivideRuleHandle ruleHandle = GsonUtils.getInstance().fromJson(rule.getHandle(), DivideRuleHandle.class);
        //获取访问的服务地址，这是是8188，8189两条
        final List<DivideUpstream> upstreamList = UpstreamCacheManager.getInstance().findUpstreamListBySelectorId(selector.getId());
        if (CollectionUtils.isEmpty(upstreamList)) {
            log.error("divide upstream configuration error： {}", rule.toString());
            Object error = SoulResultWrap.error(SoulResultEnum.CANNOT_FIND_URL.getCode(), SoulResultEnum.CANNOT_FIND_URL.getMsg(), null);
            return WebFluxResultUtils.result(exchange, error);
        }
        final String ip = Objects.requireNonNull(exchange.getRequest().getRemoteAddress()).getAddress().getHostAddress();
       //根据权重，获取访问的服务地址
        DivideUpstream divideUpstream = LoadBalanceUtils.selector(upstreamList, ruleHandle.getLoadBalance(), ip);
        if (Objects.isNull(divideUpstream)) {
            log.error("divide has no upstream");
            Object error = SoulResultWrap.error(SoulResultEnum.CANNOT_FIND_URL.getCode(), SoulResultEnum.CANNOT_FIND_URL.getMsg(), null);
            return WebFluxResultUtils.result(exchange, error);
        }
        // set the http url
        String domain = buildDomain(divideUpstream);
        String realURL = buildRealURL(domain, soulContext, exchange);
        exchange.getAttributes().put(Constants.HTTP_URL, realURL);
        // set the http timeout
        exchange.getAttributes().put(Constants.HTTP_TIME_OUT, ruleHandle.getTimeout());
        exchange.getAttributes().put(Constants.HTTP_RETRY, ruleHandle.getRetry());
        return chain.execute(exchange);
    }

DivideUpstream divideUpstream = LoadBalanceUtils.selector(upstreamList, ruleHandle.getLoadBalance(), ip);方法为根据权重获取访问的服务地址，一路断点，最终找到RandomLoadBalance类

public DivideUpstream doSelect(final List<DivideUpstream> upstreamList, final String ip) {
        //计算总权重
        int totalWeight = calculateTotalWeight(upstreamList);
        //判断是否平均分配
        boolean sameWeight = isAllUpStreamSameWeight(upstreamList);
        if (totalWeight > 0 && !sameWeight) {
            //获取具体的访问地址信息
            return random(totalWeight, upstreamList);
        }
        // If the weights are the same or the weights are 0 then random
        return random(upstreamList);
    }

//根据权重获取具体的访问地址信息
private DivideUpstream random(final int totalWeight, final List<DivideUpstream> upstreamList) {
        // If the weights are not the same and the weights are greater than 0, then random by the total number of weights
        int offset = RANDOM.nextInt(totalWeight);
        // Determine which segment the random value falls on
        for (DivideUpstream divideUpstream : upstreamList) {
            offset -= getWeight(divideUpstream);
            if (offset < 0) {
                return divideUpstream;
            }
        }
        return upstreamList.get(0);
    }

至此，devide 插件负载均衡权重分析告一段落。