Question

我开始在我的应用程序上使用Hystrix来处理来自外部服务的数据。我的代码中的一些要点：

const fs = require('fs')
const http = require('http')
const os = require('os')
const path = require('path')

startServer() {
  // GETTING NETWORK IP OF THE SERVER (ipv4, e.g. 192.168.0.x)
  var interfaces = os.networkInterfaces()
  var addresses = []
  for (var k in interfaces) {
      for (var k2 in interfaces[k]) {
          var address = interfaces[k][k2];
          if (address.family === 'IPv4' && !address.internal) {
              addresses.push(address.address)
          }
      }
  }
  var filtered = addresses.filter(x => x.includes("192.168.0"))

  // SERVING FILE FOR OTHER LOCAL DEVICES
  const hostname = filtered
  const port = 8080
  var fileName = "1.png"
  var filePath = path.join("C:/Users/u/Desktop", fileName)

  const server = http.createServer((req, res) => {
    var stat = fs.statSync(filePath);

    res.writeHead(200, {
        'Content-Type': 'application/octet-stream',
        "Content-Disposition": "attachment; filename=" + fileName
    });

    var readStream = fs.createReadStream(filePath);
    // replacing all the event handlers with a simple call to readStream.pipe()
    readStream.pipe(res);

  })

  server.listen(port, hostname, () => {
   console.log(`Server running at http://${hostname}:${port}/`)
  }) 
}

在我的单元测试中，我想测试后备情况，例如当外部服务返回404 Not Found响应时，所以我模拟我的测试如下：

@HystrixCommand(fallbackMethod = "getImagesFallback")
public ImageResultResource getImages(String url) 
{
    ResponseEntity<ResultResource> result = restTemplate.exchange(url, HttpMethod.GET, new HttpEntity<>(getRequestHeaders()), ResultResource.class);
    return result.getBody().getImageResultResource();
}

public ImageResultResource getImagesFallback(String url, Throwable e) 
{
    return new ImageResultResource();
}

但是当我运行测试时，似乎我没有调用上面定义的fallbackMethod。它直接返回我找不到的404 Not Found，我预计应该在这里捕获fallbackMethod，并且不会抛出404 Not Found。

任何人都可以给我提示如何在这种情况下测试我的fallbackMethod，还是我在这里配置有问题？非常感谢你！

Answer 1

您的回退方法需要与具有HystrixCommand注释的方法具有相同的签名，或者具有添加Throwable的相同签名。 Here是相关的Javanica文档

public ImageResultResource getImagesFallback(String url, Throwable e) {
    return new ImageResultResource();
}

Answer 2

Hystrix自定义回退方法抛出具有HystrixRuntimeException实例的异常。因此，您需要捕获此异常并使用它的getMessage方法进行打印。

在单元测试中不会调用Hystrix fallbackMethod？

2 个答案: