.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！