Soul网关源码分析-6期

今日任务

• AlibabaDubboPlugin 研究
• ApacheDubboPlugin 研究

AlibabaDubboPlugin

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将该启动的都开启, Mysql、Zookeeper、AlibabaDubbo服务、Soul-admin、Soul-bootstrap.

值得注意的是, 启动网关时打印了这几行日志:

2021-01-19 19:56:44.680  INFO 1623 --- [ctReadThread-37] o.d.s.p.a.d.c.ApplicationConfigCache     : init aliaba dubbo reference success there meteData is :MetaData(id=1350474912353136640, appName=dubbo, contextPath=null, path=/dubbo/insert, rpcType=dubbo, serviceName=org.dromara.soul.test.dubbo.api.service.DubboTestService, methodName=insert, parameterTypes=org.dromara.soul.test.dubbo.api.entity.DubboTest, rpcExt={
   "timeout":10000}, enabled=true)
2021-01-19 19:56:44.829  INFO 1623 --- [ctReadThread-37] o.d.s.p.a.d.c.ApplicationConfigCache     : init aliaba dubbo reference success there meteData is :MetaData(id=1350474914580312064, appName=dubbo, contextPath=null, path=/dubbo/findByIdsAndName, rpcType=dubbo, serviceName=org.dromara.soul.test.dubbo.api.service.DubboMultiParamService, methodName=findByIdsAndName, parameterTypes=java.util.List,java.lang.String, rpcExt={
   "timeout":10000}, enabled=true)

看着像服务信息缓存相关, 先记下 `ApplicationConfigCache` 这个类.

这次我们有了以前的经验, 直接找到 SoulWebHandler 的 execute() 方法, 看看调用的插件链长啥样:

plugins = {ArrayList@8953}  size = 12
 0 = {GlobalPlugin@8537} 
 1 = {WafPlugin@9085} 
 2 = {RateLimiterPlugin@9086} 
 3 = {HystrixPlugin@9087} 
 4 = {DividePlugin@9088} 
 5 = {WebClientPlugin@9089} 
 6 = {WebSocketPlugin@9090} 
 7 = {BodyParamPlugin@9091} 
 8 = {AlibabaDubboPlugin@9092} 
 9 = {MonitorPlugin@9093} 
 10 = {WebClientResponsePlugin@9094} 
 11 = {DubboResponsePlugin@9095} 

比起简单的HTTP调用, 多了两个插件 BodyParamPlugin 、AlibabaDubboPlugin 、DubboResponsePlugin, 这两个应该就是 Dubbo 服务相关的插件了.

继续跑跑链调用, 像之前的老熟人 DividePlugin 、WebClientPlugin 、WebClientResponsePlugin 和 WebSocketPlugin 都直接跳过了, 能理解, 毕竟走的 RpcType 类型为 dubbo.

最后再关注下线程变动信息, 因为有服务调用肯定应该是要异步的, 这里不是在调用服务就是准备调用, 总之它不老实就是了:

可以从以下截图看到, 插件调用在 BodyParamPlugin 到 AlibabaDubboPlugin 间线程发生变动, 看来 BodyParamPlugin 是关键的请求转发插件, 我们从它来开刀, 跟踪它的代码.

PS: 这里注意下, 此处 BodyParamPlugin 完整路径为: org.dromara.soul.plugin.alibaba.dubbo.param

public class BodyParamPlugin implements SoulPlugin {
   
	@Override
  public Mono<Void> execute(final ServerWebExchange exchange, final SoulPluginChain chain) {
   
    final ServerHttpRequest request = exchange.getRequest();
    final SoulContext soulContext = exchange.getAttribute(Constants.CONTEXT);
    if (Objects.nonNull(soulContext) && RpcTypeEnum.DUBBO.getName().equals(soulContext.getRpcType())) {
   
      // 获取请求头的 contentType
      MediaType mediaType = request.getHeaders().getContentType();
      ServerRequest serverRequest = ServerRequest.create(exchange, messageReaders);
      return serverRequest.bodyToMono(String.class)
        .switchIfEmpty(Mono.defer(() ->
                                  // 切换线程了
                                  Mono.just(""))
                      )
        .flatMap(body -> {
   
          // 判断 contentType 是否 json, 是则将 body 信息注入上下文, 用 key 标识是 dubbo参数
          if (MediaType.APPLICATION_JSON.isCompatibleWith(mediaType)) {
   
            exchange.getAttributes().put(Constants.DUBBO_PARAMS, body)