.net framework 4.5 +steeltoe+ springcloud（三）实现Hystrix断路器

在基于.net framework的服务客户端实现断路器功能，基本项目创建步骤可以参照我的另一篇发现和调用服务的笔记，地址：http://www.cnblogs.com/troytian/p/8621861.html

 

在客户端能实现服务调用基础上，我们首先需要在appsettings.json中添加Hystrix配置：

 "hystrix": {
     "command": {
       "FortuneService": {
         "threadPoolKeyOverride": "FortuneServiceTPool"
       }
     },
     "stream": {
       "validate_certificates": false
     }
   },

 

 

 

 

在程序入口对断路器进行注册：

 

  protected void Application_Start()
         {
             AreaRegistration.RegisterAllAreas();
             FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
             RouteConfig.RegisterRoutes(RouteTable.Routes);
             BundleConfig.RegisterBundles(BundleTable.Bundles);

             ApplicationConfig.RegisterConfig("development");

             var builder = new ContainerBuilder();

             // Add Microsoft Options to container
             builder.RegisterOptions();

             // Add Microsoft Logging to container
             builder.RegisterLogging(ApplicationConfig.Configuration);

             // Add Console logger to container
             builder.RegisterConsoleLogging();

             // Register all the controllers with Autofac
             builder.RegisterControllers(typeof(MvcApplication).Assembly);

             // Register IDiscoveryClient, etc.
             builder.RegisterDiscoveryClient(ApplicationConfig.Configuration);

             // Register FortuneService Hystrix command
             builder.RegisterHystrixCommand<IFetchServise, FetchServise>("fetchServise", ApplicationConfig.Configuration);

             // Register Hystrix Metrics/Monitoring stream
             //builder.RegisterHystrixMetricsStream(ApplicationConfig.Configuration);

             // Create the Autofac container
             var container = builder.Build();
             DependencyResolver.SetResolver(new AutofacDependencyResolver(container));

             // Get a logger from container
             var logger = container.Resolve<ILogger<MvcApplication>>();

             logger.LogInformation("Finished container build, starting background services");

             // Start the Discovery client background thread
             container.StartDiscoveryClient();

             // Start the Hystrix Metrics stream
             //container.StartHystrixMetricsStream();

             logger.LogInformation("Finished starting background services");
         }

 

 

然后需要修改服务调用的方式，添加断路器fallback回调功能，FetchServise.cs：

 public class FetchServise : HystrixCommand<string>, IFetchServise
     {
         DiscoveryHttpClientHandler _handler;

         private const string RANDOM_FORTUNE_URL = "http://java-service/hi?name=tian";
         private ILogger<FetchServise> _logger;

         public FetchServise(IHystrixCommandOptions options, IDiscoveryClient client, ILoggerFactory logFactory = null) : base(options)
         {
             _handler = new DiscoveryHttpClientHandler(client, logFactory?.CreateLogger<DiscoveryHttpClientHandler>());
             IsFallbackUserDefined = true;
             _logger = logFactory?.CreateLogger<FetchServise>();
         }

         public async Task<string> RandomFortuneAsync()
         {
             _logger?.LogInformation("RandomFortuneAsync");
             var result = await ExecuteAsync();
             _logger?.LogInformation("RandomFortuneAsync returning: " + result);
             return result;
         }

         protected override async Task<string> RunAsync()
         {
             _logger?.LogInformation("RunAsync");
             var client = GetClient();
             var result = await client.GetStringAsync(RANDOM_FORTUNE_URL);
             _logger?.LogInformation("RunAsync returning: " + result);
             return result;
         }

         protected override async Task<string> RunFallbackAsync()
         {
             _logger?.LogInformation("RunFallbackAsync");
             return await Task.FromResult("服务断开，请稍后重试!");
         }

         private HttpClient GetClient()
         {
             var client = new HttpClient(_handler, false);
             return client;
         }
     }

 

 

现在我们断开java-service服务，再启动程序看看，会不会调用熔断机制，如果调用了则页面会显示我们设定好的提示语【服务断开，请稍后重试!】：

成功！