关于微服务:Producer处理客户端请求线程模型分析

Producer线程模型剖析

线程传递过程：网络eventloop线程接管申请->传给group线程解决->group解决完后->返还给网络线程去响应

eventloop线程找业务线程:通过查找operationMeta获取,operationMeta是存储解决业务逻辑元数据信息，代码AbstractRestInvocation中体现这一过程

    try {      operationMeta.getExecutor().execute(() -> {        synchronized (this.requestEx) {          try {            if (isInQueueTimeout()) {              throw new InvocationException(Status.INTERNAL_SERVER_ERROR, "Timeout when processing the request.");            }            if (requestEx.getAttribute(RestConst.REST_REQUEST) != requestEx) {              // already timeout              // in this time, request maybe recycled and reused by web container, do not use requestEx              LOGGER.error("Rest request already timeout, abandon execute, method {}, operation {}.",                  operationMeta.getHttpMethod(),                  operationMeta.getMicroserviceQualifiedName());              return;            }            runOnExecutor();          } catch (InvocationException e) {            LOGGER.error("Invocation failed, cause={}", e.getMessage());            sendFailResponse(e);          } catch (Throwable e) {            LOGGER.error("Processing rest server request error", e);            sendFailResponse(e);          }        }      });    } catch (Throwable e) {      LOGGER.error("failed to schedule invocation, message={}, executor={}.", e.getMessage(), e.getClass().getName());      sendFailResponse(e);    }

业务线程找eventloop线程:eventloop网络线程在放到responseEx上下文中，这个在VertxRestDispatcher能够看到responseEx预置了网络线程

    HttpServletResponseEx responseEx = new VertxServerResponseToHttpServletResponse(context.response());//vertx context 设置  public VertxServerResponseToHttpServletResponse(HttpServerResponse serverResponse) {    this.context = Vertx.currentContext();    this.serverResponse = serverResponse;    Objects.requireNonNull(context, "must run in vertx context.");  }

线程切换过程具体

1.接管申请的vertx eventloop线程

2.从vertx eventloop线程转入业务线程解决

3.进入ProducerOperationHandler的handler，依然是业务线程group

4.进入ProducerOperationHandler的syncInvoke的,最终进入sendResponseQuietly,线程依然是group

// ProducerOperationHandler的asyncResp  public void syncInvoke(Invocation invocation, SwaggerProducerOperation producerOperation, AsyncResponse asyncResp) {....    asyncResp.handle(response);  }//上述的asyncResp正是AbstractRestInvocation传进去的sendResponseQuietly  protected void doInvoke() throws Throwable {    invocation.onStartHandlersRequest();    invocation.next(resp -> sendResponseQuietly(resp));  }

5.响应 group线程，通过驱动responseEx去响应,把响应交由eventloop线程去解决，eventloop线程在responseEx的context，即context.runOnContext(V -> internalFlushBuffer());

// responseEx  protected void onExecuteHttpServerFiltersFinish(Response response, Throwable e) {...      responseEx.flushBuffer();...}// 进入VertxServerResponseToHttpServletResponse的flushBuffer  public void flushBuffer() {    if (context == Vertx.currentContext()) {      internalFlushBuffer();      return;    }    context.runOnContext(V -> internalFlushBuffer());  }//通过serverResponse.end(bodyBuffer)发送响应，vertx框架做的事件  public void internalFlushBuffer() {...    serverResponse.end(bodyBuffer);  }