.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！