Asp。NetCore自定义配置中心客户端

　　说明：下面的实例是通过阅读Nacos的SDK源码，提取出来的关键实现。
　　Asp.Net core添加一个自定义配置，只要通过IConfigurationBuilder的Add方法，传递一个实现了IConfigurationSource接口实例即可。
　　先定义一个NiuBConfigSource，实现接口IConfigurationSource    public class NiuBConfigSource : NiuBOption, IConfigurationSource     {         public IConfigurationProvider Build(IConfigurationBuilder builder)         {               throw new NotImplementedException();         }     }
　　这时候，Build方法需要返回一个IConfigurationProvider的实例，那么再来定义一个IConfigurationProvider的实现类，直接继承.Net框架定义好的类ConfigurationProvider，该类实现了IConfigurationProvider接口。覆写一下Load方法，为后续的配置更新刷新内存配置做准备，重载一个Load方法，传一个键值对进来，调用原来的Load方法，实现对内存的刷新。    public class NiuBConfigProvider : ConfigurationProvider     {         private Dictionary innerCnfiguration = new Dictionary();         public override void Load()         {             foreach (string key in innerCnfiguration.Keys)             {                 base.Data[key] = innerCnfiguration[key];             }             base.Load();         }          internal void Load(Dictionary configuration)         {             this.innerCnfiguration = configuration;             this.Load();         }     }
　　这时候NiuBConfigSource就可以返回一个IConfigurationProvider实例了    public class NiuBConfigSource :  IConfigurationSource     {         public IConfigurationProvider Build(IConfigurationBuilder builder)         {             return new NiuBConfigProvider(service);         }     }
　　为了方便使用，定义一个WebApplicationBuilder的扩展方法UseNiuBConfigure    public static class NiuBConfigProviderExtension     {         public static IConfigurationBuilder UseNiuBConfigure(this WebApplicationBuilder builder)         {             NiuBConfigSource source = new NiuBConfigSource();             IConfigurationBuilder configBuilder = builder.Configuration;             return configBuilder.Add(source);         }     }
　　那么来看一下怎么使用？var builder = WebApplication.CreateBuilder(args); builder.UseNiuBConfigure();
　　嗯，看起来不错了，那么问题来了，如果配置中心更新了配置，怎么刷新内存配置数据呢？
　　没错NiuBConfigProvider有个Load的方法。
　　我们先改造一下UseNiuBConfigure方法，把配置中心的请求服务地址信息传递进去        public static IConfigurationBuilder UseNiuBConfigure(this WebApplicationBuilder builder, Action configure)         {             NiuBOption option= new NiuBOption();             configure(option);             NiuBConfigSource source = new NiuBConfigSource();             IConfigurationBuilder configBuilder = builder.Configuration;             return configBuilder.Add(source);         }
　　NiuBOption的定义    public class NiuBOption     {         public string ConfigSectionName { get; set; }         public string Host { get; set; }         public string Port { get; set; }     }
　　定义个监听器    public class Listener     {         NiuBConfigProvider provider;         public Listener(NiuBConfigProvider provider)         {             this.provider = provider;         }          public void ConfigurationChanged(Dictionary configuration)         {             provider.Load(configuration);         }     }
　　定义一个监听服务public class NiuBService : INiuBService     {         // 启动远程监听，比如         public NiuBService()         {             Start();         }          // 配置中心的代码没有实现，通过该方法进行测试         private void grpcAccept(string host, string port, string configSectionName)         {             new ConfigureCenter().ConfigureChanged += configuration=> Configure(configuration);         }         // 该方法在UseNiuBConfigure方法中服务注入的时候会调用         // 根据配置信息，启动远程监听，比如用GRPC的双工通信，socket通信         public void Start()         {             Console.WriteLine(＂begin listen to xxx监听配置中心＂);             // 如果有新的更新，那么调用Configure方法             grpcAccept(this.Option?.Host, this.Option?.Port, this.Option?.ConfigSectionName);                 }          public void Restart(Dictionary options)         {             this.Option.Host = options[＂Host＂];             this.Option.Host = options[＂Port＂];             this.Start();         }          public NiuBOption Option { get; set; }          public List Listeners { get; set; } = new List();          public void Configure(Dictionary configuration)         {             foreach (var listener in Listeners)             {                 listener.ConfigurationChanged(configuration);             }         }     }
　　现在UseNiuBConfigure方法的实现变成了这样        public static IConfigurationBuilder UseNiuBConfigure(this WebApplicationBuilder builder, Action configure)         {             NiuBOption option= new NiuBOption();             configure(option);             var service= new NiuBService();             NiuBConfigSource source = new NiuBConfigSource(service);             service.Option= option;             builder.Services.addNiuBConfig(service);             IConfigurationBuilder configBuilder = builder.Configuration;             return configBuilder.Add(source);         }
　　NiuBConfigProvider的实现修改为    public class NiuBConfigProvider : ConfigurationProvider     {         private INiuBService service { get; set; }         public NiuBConfigProvider(INiuBService service) {              this.service = service;             service.Listeners.Add(new Listener(this));         }         private Dictionary innerCnfiguration = new Dictionary();         public override void Load()         {             foreach (string key in innerCnfiguration.Keys)             {                 base.Data[key] = innerCnfiguration[key];                 if (key == ＂ConfigCenterOption＂) {//热重启配置监听服务                     service.Restart(innerCnfiguration);                 }             }             base.Load();         }          internal void Load(Dictionary configuration)         {             this.innerCnfiguration = configuration;             this.Load();         }     }
　　NiuBConfigSource把Service传递进去    public class NiuBConfigSource : NiuBOption, IConfigurationSource     {         private INiuBService service;         public NiuBConfigSource(INiuBService service)         {             this.service = service;         }         public IConfigurationProvider Build(IConfigurationBuilder builder)         {             return new NiuBConfigProvider(service);         }     }
　　事情搞完了，下面来测试一下，由于注册中心没有实现，下面来模拟一下       // 配置中心的代码没有实现，通过该方法模拟监听         private void grpcAccept(string host, string port, string configSectionName)         {             ConfigureCenter.ConfigureChanged += configuration=> Configure(configuration);         }
　　ConfigureCenter的实现    public class ConfigureCenter     {         public ConfigureCenter() { }         public event Action> ConfigureChanged;          public void PublishConfig(Dictionary config)         {             if (this.ConfigureChanged != null)             {                 ConfigureChanged(config);             }         }     }
　　模拟配置中心发布了新的配置var service= app.Services.GetService();  service.ConfigureCenter.PublishConfig(new Dictionary() {     { ＂OrderService＂,＂{＂Host＂:＂http://niubi.com/api/order＂,＂descript＂:＂订单服务地址＂}＂} });
　　通过API查看是否能获取到配置中心发布的配置    [Route(＂api/[Controller]＂)]     public class OrderController : ControllerBase     {         public IConfiguration Configuration { get; set; }           public OrderController(IConfiguration configuration )         {             this.Configuration = configuration;                      }         [HttpGet]         public string Get()         {             var value= Configuration[＂OrderService＂];             return value == null ?  ＂Empty＂: value;         }     }
　　请求结果