首先看一下几种注册中心：
最老的就是Zookeeper了， 比较新的有Eureka，Consul 都可以做注册中心。可以自行搜索对比三者的优缺点。
Zookeeper 最开始就是hadoop大家族中的一员，用于做协调的框架，后来已经是apache的子项目了。
几年前大数据很火的时候，只要学hadoop必学zookeeper，当然还有其他成员。
大数据简单说就是分布式，比如分布式文件存储hdfs，分布式数据库hbase，分布式协调zookeeper，还有kafka，Flume等等都是hadoop大家族。
zookeeper，现在更多被用来做注册中心，比如阿里的开源SOA框架dubbo就经常搭配zookeeper做注册中心。
Eureka：java的微服务框架Spring Cloud中内部已经集成了Eureka注册中心。
我选择zookeeper，不是因为他比另外两个强，而是因为我几年前就已经学习过一些zookeeper的原理，上手更容易。网络上学习书籍、资料、视频教程也特别多，学习资料完善。
注册中心的基本功能：
1. 注册服务，有点类似DNS，所有的服务注册到注册中心，包含服务的地址等信息。
2. 服务订阅，客户端请求服务，注册中心就要把那些能用的服务器地址告诉客户端，服务端有变动时，注册中心也能及时通知到客户端。
3. 性能好且高可用，注册中心自身也是一个集群，如果只有一个注册中心机器的话那岂不是把注册中心累死啊，而且他一旦坏了以后，那客户端都找不到服务器了。所有注册中心就有很多台，其中只有一个老大（leader），老大用来写，小弟用来读。就是说老大来决定一台服务器能不能注册进来，小弟负责帮助客户端查找服务器。因为注册服务的次数是很少的，通常有新服务器加入才需要注册，但是客户端订阅那就很多了，所以注册中心只有一个leader。leader万一坏掉的话，会从小弟中选举出一个来当老大接替工作。
上面提到说zookeeper集群，就是说有很多台机器做zookeeper机器，但是这些机器里存储的东西基本上都是一样的，就是说客户端不管连到哪个zookeeper 都是一样的，能做服务订阅。
每一个zookeeper 中都有很多节点（Znode）。
接下来说的zookeeper节点和集群完全不是一回事。 有些人喜欢吧集群中的每一台zookeeper机器称为一个节点，但是这个节点（zookeeper机器）和我说的节点（Znode）完全不是一回事。
如下图：
本例的图中可以看到，一共有5台机器，每台机器都有5个znode，Znode下面的子节点就更多了。
先看5台机器：
一台leader，老大，上文已经介绍，服务都从这些注册写入。
两台follower，小弟，平时用于服务订阅，老大挂掉以后，follower内部就会自行选出老大。
两台observer，观察者，就是属于无业游民，只能看，没有选老大的资格，不能参与竞选也不能投票，唯一的功能就是服务订阅。
observer模式需要手动开启，为什么会出现observer呢，是因为机器太多的话，每个机器都有选举权的话特别影响性能。全中国14亿人口，每个人都参与国家竞选的话，效率极低。所以呢，选举的工作就交给follower完成就行了，只需要确保一直都有leader接班人就好。
再看看zookeeper有什么基本功能：
基本功能很简单，组合以后却可以完成各种复杂工作。
1. 可以创建：临时节点（断开连接时便删除节点） 和 持久化节点（必须手动删除节点）。
2. 可以创建：无序节点 和 有序节点。
3. 节点上可以添加watcher监听功能，监听该节点的增删改，然后触发自定义的事件。
看看这些功能怎么用：
1. 节点： 每次注册一个服务就创建一个节点，节点的名称（Key）就是服务的名称，服务的详细信息存储在节点value中，客户端通过key找到对应的节点，再找打节点中的value。
2. 临时节点：服务端注册一个服务时创建一个临时节点，服务断开时，临时节点自动销毁，自动完成服务注销。
3. watcher监听： 客户端在注册中心订阅了一个服务的时候，同时在这个服务所在的节点上加一个监听事件，每当服务节点信息有变化的时候，注册中心会自动回调通知客户端。
4. 有序临时节点：分布式锁或者分布式队列（这里与服务注册无关），客户端1想要操作一条数据的时候，在A节点下创建一个有序临时节点，自动分配编号001；客户端1也要操作该数据的时候，在A节点下也创建一个有序临时节点，自动分配编号002。只有编号最小的子节点才会被执行，因此001节点会被执行，客户端1执行完毕后，自动删除001节点，此时002编号为最小子节点。即锁的概念，不能同时操作同一数据；也可以做队列，按照先后顺序依次执行。
5. 有序临时节点+watcher监听： 上面第4条中说到每次执行编号最小的节点，因此需要有一个程序，每次都需要遍历全部节点，然后找出最小的节点，假如是002节点，这时客户端2开始执行。但是添加监听机制以后就不一样了，002监听001,003监听比他小一号的002，这样001销毁的同时通知002开始执行，002销毁的时候通知003开始执行，不需要遍历最小节点，也能有序依次执行。
6. 临时节点+watcher监听： 集群master选举以及高可用。比如hadoop集群，也有一个resourcemanager资源管理器，负责调度其它节点机器，相当于hadoop集群的leader节点。这个leader就可以交由zookeeper管理，所有的hadoop机器同时在zookeeper中创建一个同名的临时节点，由于是同名互斥的节点，因此只有一个节点能被创建，成功创建这个节点的hadoop机器就是leader。同时添加Watcher监听，这个leader只要断开连接，临时节点自动销毁，触发监听，其它hadoop开始新一轮的master选举。这也是zookeeper最初在hadoop家族中的重要使命。
7....... 还要很多地方都能用zookeeper，简直无所不能，而且自身也是高可用，高性能，牛x
zookeeper本身的操作还是很简单的，无非就是节点的增删改查，可以选择要创建节点的类型，还有就是在节点上添加watcher监听器。就这些。
文件结构：
上代码：
zookeeper客户端管理类：
public class ZookeeperClientProvider { private ConfigInfo _config; private readonly ILogger<ZookeeperClientProvider> _logger; private readonly Dictionary<string, ZooKeeper> _zookeeperClients = new Dictionary<string, ZooKeeper>(); public ZookeeperClientProvider(ConfigInfo config, ILogger<ZookeeperClientProvider> logger) { _config = config; _logger = logger; } public async Task<ZooKeeper> GetZooKeeper() { return await CreateZooKeeper(_config.Addresses.FirstOrDefault()); } public async Task<ZooKeeper> CreateZooKeeper(string address) { if (!_zookeeperClients.TryGetValue(address, out ZooKeeper result)) { await Task.Run(() => { result = new ZooKeeper(address, (int)_config.SessionTimeout.TotalMilliseconds, new ReconnectionWatcher( async () => { if (_zookeeperClients.Remove(address, out ZooKeeper value)) { await value.closeAsync(); } await CreateZooKeeper(address); })); _zookeeperClients.TryAdd(address, result); }); } return result; } public async Task<IEnumerable<ZooKeeper>> GetZooKeepers() { var result = new List<ZooKeeper>(); foreach (var address in _config.Addresses) { result.Add(await CreateZooKeeper(address)); } return result; } }
zookeeper服务注册类：
/// <summary> /// 一个抽象的服务路由发现者。 /// </summary> public interface IServiceRouteManager { /// <summary> /// 服务路由被创建。 /// </summary> event EventHandler<ServiceRouteEventArgs> Created; /// <summary> /// 服务路由被删除。 /// </summary> event EventHandler<ServiceRouteEventArgs> Removed; /// <summary> /// 服务路由被修改。 /// </summary> event EventHandler<ServiceRouteChangedEventArgs> Changed; /// <summary> /// 获取所有可用的服务路由信息。 /// </summary> /// <returns>服务路由集合。</returns> Task<IEnumerable<ServiceRoute>> GetRoutesAsync(); /// <summary> /// 设置服务路由。 /// </summary> /// <param name="routes">服务路由集合。</param> /// <returns>一个任务。</returns> Task SetRoutesAsync(IEnumerable<ServiceRoute> routes); /// <summary> /// 移除地址列表 /// </summary> /// <param name="routes">地址列表。</param> /// <returns>一个任务。</returns> Task RemveAddressAsync(IEnumerable<string> Address); /// <summary> /// 清空所有的服务路由。 /// </summary> /// <returns>一个任务。</returns> Task ClearAsync(); } /// <summary> /// 服务路由事件参数。 /// </summary> public class ServiceRouteEventArgs { public ServiceRouteEventArgs(ServiceRoute route) { Route = route; } /// <summary> /// 服务路由信息。 /// </summary> public ServiceRoute Route { get; private set; } } /// <summary> /// 服务路由变更事件参数。 /// </summary> public class ServiceRouteChangedEventArgs : ServiceRouteEventArgs { public ServiceRouteChangedEventArgs(ServiceRoute route, ServiceRoute oldRoute) : base(route) { OldRoute = oldRoute; } /// <summary> /// 旧的服务路由信息。 /// </summary> public ServiceRoute OldRoute { get; set; } }
public class ZooKeeperServiceRouteManager : IServiceRouteManager, IDisposable { private readonly ConfigInfo _configInfo; private readonly ISerializer<byte[]> _serializer; private readonly ILogger<ZooKeeperServiceRouteManager> _logger; private ServiceRoute[] _routes; private readonly ZookeeperClientProvider _zookeeperClientProvider; public ZooKeeperServiceRouteManager(ConfigInfo configInfo, ISerializer<byte[]> serializer, ISerializer<string> stringSerializer, ILogger<ZooKeeperServiceRouteManager> logger, ZookeeperClientProvider zookeeperClientProvider) { _configInfo = configInfo; _serializer = serializer; _logger = logger; _zookeeperClientProvider = zookeeperClientProvider; EnterRoutes().Wait(); } private EventHandler<ServiceRouteEventArgs> _created; private EventHandler<ServiceRouteEventArgs> _removed; private EventHandler<ServiceRouteChangedEventArgs> _changed; /// <summary> /// 服务路由被创建。 /// </summary> public event EventHandler<ServiceRouteEventArgs> Created { add { _created += value; } remove { _created -= value; } } /// <summary> /// 服务路由被删除。 /// </summary> public event EventHandler<ServiceRouteEventArgs> Removed { add { _removed += value; } remove { _removed -= value; } } /// <summary> /// 服务路由被修改。 /// </summary> public event EventHandler<ServiceRouteChangedEventArgs> Changed { add { _changed += value; } remove { _changed -= value; } } protected void OnCreated(params ServiceRouteEventArgs[] args) { if (_created == null) return; foreach (var arg in args) _created(this, arg); } protected void OnChanged(params ServiceRouteChangedEventArgs[] args) { if (_changed == null) return; foreach (var arg in args) _changed(this, arg); } protected void OnRemoved(params ServiceRouteEventArgs[] args) { if (_removed == null) return; foreach (var arg in args) _removed(this, arg); } /// <summary> /// 获取所有可用的服务路由信息。 /// </summary> /// <returns>服务路由集合。</returns> public async Task<IEnumerable<ServiceRoute>> GetRoutesAsync() { await EnterRoutes(); return _routes; } /// <summary> /// 清空所有的服务路由。 /// </summary> /// <returns>一个任务。</returns> public async Task ClearAsync() { if (_logger.IsEnabled(LogLevel.Information)) _logger.LogInformation("准备清空所有路由配置。"); var zooKeepers = await _zookeeperClientProvider.GetZooKeepers(); foreach (var zooKeeper in zooKeepers) { var path = _configInfo.RoutePath; var childrens = path.Split(new[] { '/' }, StringSplitOptions.RemoveEmptyEntries); var index = 0; while (childrens.Count() > 1) { var nodePath = "/" + string.Join("/", childrens); if (await zooKeeper.existsAsync(nodePath) != null) { var result = await zooKeeper.getChildrenAsync(nodePath); if (result?.Children != null) { foreach (var child in result.Children) { var childPath = $"{nodePath}/{child}"; if (_logger.IsEnabled(LogLevel.Debug)) _logger.LogDebug($"准备删除：{childPath}。"); await zooKeeper.deleteAsync(childPath); } } if (_logger.IsEnabled(LogLevel.Debug)) _logger.LogDebug($"准备删除：{nodePath}。"); await zooKeeper.deleteAsync(nodePath); } index++; childrens = childrens.Take(childrens.Length - index).ToArray(); } if (_logger.IsEnabled(LogLevel.Information)) _logger.LogInformation("路由配置清空完成。"); } } /// <summary> /// 设置服务路由。 /// </summary> /// <param name="routes">服务路由集合。</param> /// <returns>一个任务。</returns> public async Task SetRoutesAsync(IEnumerable<ServiceRoute> routes) { var hostAddr = NetUtils.GetHostAddress(); var serviceRoutes = await GetRoutes(routes.Select(p => p.serviceRouteDescriptor.Id)); if (serviceRoutes.Count() > 0) { foreach (var route in routes) { var serviceRoute = serviceRoutes.Where(p => p.serviceRouteDescriptor.Id == route.serviceRouteDescriptor.Id).FirstOrDefault(); if (serviceRoute != null) { var addresses = serviceRoute.Address.Concat( route.Address.Except(serviceRoute.Address)).ToList(); foreach (var address in route.Address) { addresses.Remove(addresses.Where(p => p.ToString() == address.ToString()).FirstOrDefault()); addresses.Add(address); } route.Address = addresses; } } } await RemoveExceptRoutesAsync(routes, hostAddr); if (_logger.IsEnabled(LogLevel.Information)) _logger.LogInformation("准备添加服务路由。"); var zooKeepers = await _zookeeperClientProvider.GetZooKeepers(); foreach (var zooKeeper in zooKeepers) { await CreateSubdirectory(zooKeeper, _configInfo.RoutePath); var path = _configInfo.RoutePath; if (!path.EndsWith("/")) path += "/"; routes = routes.ToArray(); foreach (var serviceRoute in routes) { var nodePath = $"{path}{serviceRoute.serviceRouteDescriptor.Id}"; var nodeData = _serializer.Serialize(serviceRoute); if (await zooKeeper.existsAsync(nodePath) == null) { if (_logger.IsEnabled(LogLevel.Debug)) _logger.LogDebug($"节点：{nodePath}不存在将进行创建。"); await zooKeeper.createAsync(nodePath, nodeData, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT); } else { if (_logger.IsEnabled(LogLevel.Debug)) _logger.LogDebug($"将更新节点：{nodePath}的数据。"); var onlineData = (await zooKeeper.getDataAsync(nodePath)).Data; if (!DataEquals(nodeData, onlineData)) await zooKeeper.setDataAsync(nodePath, nodeData); } } if (_logger.IsEnabled(LogLevel.Information)) _logger.LogInformation("服务路由添加成功。"); } } public async Task RemveAddressAsync(IEnumerable<string> Address) { var routes = await GetRoutesAsync(); foreach (var route in routes) { route.Address = route.Address.Except(Address); } await SetRoutesAsync(routes); } private async Task RemoveExceptRoutesAsync(IEnumerable<ServiceRoute> routes, string hostAddr) { var path = _configInfo.RoutePath; if (!path.EndsWith("/")) path += "/"; routes = routes.ToArray(); var zooKeepers = await _zookeeperClientProvider.GetZooKeepers(); foreach (var zooKeeper in zooKeepers) { if (_routes != null) { var oldRouteIds = _routes.Select(i => i.serviceRouteDescriptor.Id).ToArray(); var newRouteIds = routes.Select(i => i.serviceRouteDescriptor.Id).ToArray(); var deletedRouteIds = oldRouteIds.Except(newRouteIds).ToArray(); foreach (var deletedRouteId in deletedRouteIds) { var addresses = _routes.Where(p => p.serviceRouteDescriptor.Id == deletedRouteId).Select(p => p.Address).FirstOrDefault(); if (addresses.Contains(hostAddr)) { var nodePath = $"{path}{deletedRouteId}"; await zooKeeper.deleteAsync(nodePath); } } } } } private async Task CreateSubdirectory(ZooKeeper zooKeeper, string path) { if (await zooKeeper.existsAsync(path) != null) return; if (_logger.IsEnabled(LogLevel.Information)) _logger.LogInformation($"节点{path}不存在，将进行创建。"); var childrens = path.Split(new[] { '/' }, StringSplitOptions.RemoveEmptyEntries); var nodePath = "/"; foreach (var children in childrens) { nodePath += children; if (await zooKeeper.existsAsync(nodePath) == null) { await zooKeeper.createAsync(nodePath, null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT); } nodePath += "/"; } } private async Task<ServiceRoute> GetRoute(byte[] data) { if (_logger.IsEnabled(LogLevel.Debug)) _logger.LogDebug($"准备转换服务路由，配置内容：{Encoding.UTF8.GetString(data)}。"); if (data == null) return null; return await Task.Run(() => { return _serializer.Deserialize<ServiceRoute>(data); }); } private async Task<ServiceRoute> GetRoute(string path) { ServiceRoute result = null; var zooKeeper = await GetZooKeeper(); var watcher = new NodeMonitorWatcher(GetZooKeeper(), path, async (oldData, newData) => await NodeChange(oldData, newData)); if (await zooKeeper.existsAsync(path) != null) { var data = (await zooKeeper.getDataAsync(path, watcher)).Data; watcher.SetCurrentData(data); result = await GetRoute(data); } return result; } private async Task<ServiceRoute[]> GetRoutes(IEnumerable<string> childrens) { var rootPath = _configInfo.RoutePath; if (!rootPath.EndsWith("/")) rootPath += "/"; childrens = childrens.ToArray(); var routes = new List<ServiceRoute>(childrens.Count()); foreach (var children in childrens) { if (_logger.IsEnabled(LogLevel.Debug)) _logger.LogDebug($"准备从节点：{children}中获取路由信息。"); var nodePath = $"{rootPath}{children}"; var route = await GetRoute(nodePath); if (route != null) routes.Add(route); } return routes.ToArray(); } private async Task EnterRoutes() { if (_routes != null) return; var zooKeeper = await GetZooKeeper(); var watcher = new ChildrenMonitorWatcher(GetZooKeeper(), _configInfo.RoutePath, async (oldChildrens, newChildrens) => await ChildrenChange(oldChildrens, newChildrens)); if (await zooKeeper.existsAsync(_configInfo.RoutePath, watcher) != null) { var result = await zooKeeper.getChildrenAsync(_configInfo.RoutePath, watcher); var childrens = result.Children.ToArray(); watcher.SetCurrentData(childrens); _routes = await GetRoutes(childrens); } else { if (_logger.IsEnabled(LogLevel.Warning)) _logger.LogWarning($"无法获取路由信息，因为节点：{_configInfo.RoutePath}，不存在。"); _routes = new ServiceRoute[0]; } } private static bool DataEquals(IReadOnlyList<byte> data1, IReadOnlyList<byte> data2) { if (data1.Count != data2.Count) return false; for (var i = 0; i < data1.Count; i++) { var b1 = data1[i]; var b2 = data2[i]; if (b1 != b2) return false; } return true; } public async Task NodeChange(byte[] oldData, byte[] newData) { if (DataEquals(oldData, newData)) return; var newRoute = await GetRoute(newData); //得到旧的路由。 var oldRoute = _routes.FirstOrDefault(i => i.serviceRouteDescriptor.Id == newRoute.serviceRouteDescriptor.Id); lock (_routes) { //删除旧路由，并添加上新的路由。 _routes = _routes .Where(i => i.serviceRouteDescriptor.Id != newRoute.serviceRouteDescriptor.Id) .Concat(new[] { newRoute }).ToArray(); } //触发路由变更事件。 OnChanged(new ServiceRouteChangedEventArgs(newRoute, oldRoute)); } public async Task ChildrenChange(string[] oldChildrens, string[] newChildrens) { if (_logger.IsEnabled(LogLevel.Debug)) _logger.LogDebug($"最新的节点信息：{string.Join(",", newChildrens)}"); if (_logger.IsEnabled(LogLevel.Debug)) _logger.LogDebug($"旧的节点信息：{string.Join(",", oldChildrens)}"); //计算出已被删除的节点。 var deletedChildrens = oldChildrens.Except(newChildrens).ToArray(); //计算出新增的节点。 var createdChildrens = newChildrens.Except(oldChildrens).ToArray(); if (_logger.IsEnabled(LogLevel.Debug)) _logger.LogDebug($"需要被删除的路由节点：{string.Join(",", deletedChildrens)}"); if (_logger.IsEnabled(LogLevel.Debug)) _logger.LogDebug($"需要被添加的路由节点：{string.Join(",", createdChildrens)}"); //获取新增的路由信息。 var newRoutes = (await GetRoutes(createdChildrens)).ToArray(); var routes = _routes.ToArray(); lock (_routes) { _routes = _routes //删除无效的节点路由。 .Where(i => !deletedChildrens.Contains(i.serviceRouteDescriptor.Id)) //连接上新的路由。 .Concat(newRoutes) .ToArray(); } //需要删除的路由集合。 var deletedRoutes = routes.Where(i => deletedChildrens.Contains(i.serviceRouteDescriptor.Id)).ToArray(); //触发删除事件。 OnRemoved(deletedRoutes.Select(route => new ServiceRouteEventArgs(route)).ToArray()); //触发路由被创建事件。 OnCreated(newRoutes.Select(route => new ServiceRouteEventArgs(route)).ToArray()); if (_logger.IsEnabled(LogLevel.Information)) _logger.LogInformation("路由数据更新成功。"); } /// <summary>Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.</summary> public void Dispose() { } private async Task<ZooKeeper> GetZooKeeper() { return await _zookeeperClientProvider.GetZooKeeper(); } }
zookeeper连接配置类：
public class ConfigInfo { /// <summary> /// 初始化会话超时为20秒的Zookeeper配置信息。 /// </summary> /// <param name="connectionString">连接字符串。</param> /// <param name="routePath">路由配置路径。</param> /// <param name="subscriberPath">订阅者配置路径</param> /// <param name="commandPath">服务命令配置路径</param> /// <param name="cachePath">缓存中心配置路径</param> /// <param name="mqttRoutePath">mqtt路由配置路径</param> /// <param name="chRoot">根节点。</param> public ConfigInfo(string connectionString, string routePath = "/services/serviceRoutes", string subscriberPath = "/services/serviceSubscribers", string commandPath = "/services/serviceCommands", string cachePath = "/services/serviceCaches", string mqttRoutePath = "/services/mqttServiceRoutes", string chRoot = null, bool reloadOnChange = false, bool enableChildrenMonitor = false) : this(connectionString, TimeSpan.FromSeconds(20), routePath, subscriberPath, commandPath, cachePath, mqttRoutePath, chRoot, reloadOnChange, enableChildrenMonitor) { } /// <summary> /// 初始化Zookeeper配置信息。 /// </summary> /// <param name="connectionString">连接字符串。</param> /// <param name="routePath">路由配置路径。</param> /// <param name="commandPath">服务命令配置路径</param> /// <param name="subscriberPath">订阅者配置路径</param> /// <param name="sessionTimeout">会话超时时间。</param> /// <param name="cachePath">缓存中心配置路径</param> /// <param name="mqttRoutePath">mqtt路由配置路径</param> /// <param name="chRoot">根节点。</param> public ConfigInfo(string connectionString, TimeSpan sessionTimeout, string routePath = "/services/serviceRoutes", string subscriberPath = "/services/serviceSubscribers", string commandPath = "/services/serviceCommands", string cachePath = "/services/serviceCaches", string mqttRoutePath = "/services/mqttServiceRoutes", string chRoot = null, bool reloadOnChange = false, bool enableChildrenMonitor = false) { CachePath = cachePath; ReloadOnChange = reloadOnChange; ChRoot = chRoot; CommandPath = commandPath; SubscriberPath = subscriberPath; ConnectionString = connectionString; RoutePath = routePath; SessionTimeout = sessionTimeout; MqttRoutePath = mqttRoutePath; EnableChildrenMonitor = enableChildrenMonitor; Addresses = connectionString?.Split(","); } public bool EnableChildrenMonitor { get; set; } public bool ReloadOnChange { get; set; } /// <summary> /// 连接字符串。 /// </summary> public string ConnectionString { get; set; } /// <summary> /// 命令配置路径 /// </summary> public string CommandPath { get; set; } /// <summary> /// 路由配置路径。 /// </summary> public string RoutePath { get; set; } /// <summary> /// 订阅者配置路径 /// </summary> public string SubscriberPath { get; set; } /// <summary> /// 会话超时时间。 /// </summary> public TimeSpan SessionTimeout { get; set; } /// <summary> /// 根节点。 /// </summary> public string ChRoot { get; set; } public IEnumerable<string> Addresses { get; set; } /// <summary> /// 缓存中心配置中心 /// </summary> public string CachePath { get; set; } /// <summary> /// Mqtt路由配置路径。 /// </summary> public string MqttRoutePath { get; set; } }
路由和路由描述：
public class ServiceRoute { /// <summary> /// 服务可用地址。 /// </summary> public IEnumerable<string> Address { get; set; } /// <summary> /// 服务描述符。 /// </summary> public ServiceRouteDescriptor serviceRouteDescriptor { get; set; } #region Equality members /// <summary>Determines whether the specified object is equal to the current object.</summary> /// <returns>true if the specified object is equal to the current object; otherwise, false.</returns> /// <param name="obj">The object to compare with the current object. </param> public override bool Equals(object obj) { var model = obj as ServiceRoute; if (model == null) return false; if (obj.GetType() != GetType()) return false; if (model.serviceRouteDescriptor != serviceRouteDescriptor) return false; return model.Address.Count() == Address.Count() && model.Address.All(addressModel => Address.Contains(addressModel)); } /// <summary>Serves as the default hash function. </summary> /// <returns>A hash code for the current object.</returns> public override int GetHashCode() { return ToString().GetHashCode(); } public static bool operator ==(ServiceRoute model1, ServiceRoute model2) { return Equals(model1, model2); } public static bool operator !=(ServiceRoute model1, ServiceRoute model2) { return !Equals(model1, model2); } #endregion Equality members }
/// <summary> /// 服务描述符。 /// </summary> [Serializable] public class ServiceRouteDescriptor { /// <summary> /// 初始化一个新的服务描述符。 /// </summary> public ServiceRouteDescriptor() { Metadatas = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase); } /// <summary> /// 服务Id。 /// </summary> public string Id { get; set; } /// <summary> /// 访问的令牌 /// </summary> public string Token { get; set; } /// <summary> /// 路由 /// </summary> public string RoutePath { get; set; } /// <summary> /// 元数据。 /// </summary> public IDictionary<string, object> Metadatas { get; set; } /// <summary> /// 获取一个元数据。 /// </summary> /// <typeparam name="T">元数据类型。</typeparam> /// <param name="name">元数据名称。</param> /// <param name="def">如果指定名称的元数据不存在则返回这个参数。</param> /// <returns>元数据值。</returns> public T GetMetadata<T>(string name, T def = default(T)) { if (!Metadatas.ContainsKey(name)) return def; return (T)Metadatas[name]; } #region Equality members /// <summary>Determines whether the specified object is equal to the current object.</summary> /// <returns>true if the specified object is equal to the current object; otherwise, false.</returns> /// <param name="obj">The object to compare with the current object. </param> public override bool Equals(object obj) { var model = obj as ServiceRouteDescriptor; if (model == null) return false; if (obj.GetType() != GetType()) return false; if (model.Id != Id) return false; return model.Metadatas.Count == Metadatas.Count && model.Metadatas.All(metadata => { object value; if (!Metadatas.TryGetValue(metadata.Key, out value)) return false; if (metadata.Value == null && value == null) return true; if (metadata.Value == null || value == null) return false; return metadata.Value.Equals(value); }); } /// <summary>Serves as the default hash function. </summary> /// <returns>A hash code for the current object.</returns> public override int GetHashCode() { return ToString().GetHashCode(); } public static bool operator ==(ServiceRouteDescriptor model1, ServiceRouteDescriptor model2) { return Equals(model1, model2); } public static bool operator !=(ServiceRouteDescriptor model1, ServiceRouteDescriptor model2) { return !Equals(model1, model2); } #endregion Equality members }
Watcher监听器：
子节点监听器：
internal class ChildrenMonitorWatcher : Watcher { private readonly Task<ZooKeeper> _zooKeeperCall; private readonly string _path; private readonly Action<string[], string[]> _action; private string[] _currentData = new string[0]; public ChildrenMonitorWatcher(Task<ZooKeeper> zooKeeperCall, string path, Action<string[], string[]> action) { _zooKeeperCall = zooKeeperCall; _path = path; _action = action; } public ChildrenMonitorWatcher SetCurrentData(string[] currentData) { _currentData = currentData ?? new string[0]; return this; } #region Overrides of WatcherBase public override async Task process(WatchedEvent watchedEvent) { if (watchedEvent.getState() != Event.KeeperState.SyncConnected || watchedEvent.getPath() != _path) return; var zooKeeper = await _zooKeeperCall; //Func<ChildrenMonitorWatcher> getWatcher = () => new ChildrenMonitorWatcher(_zooKeeperCall, path, _action); Task<ChildrenMonitorWatcher> getWatcher = Task.Run(() => {return new ChildrenMonitorWatcher(_zooKeeperCall, _path, _action); }); switch (watchedEvent.get_Type()) { //创建之后开始监视下面的子节点情况。 case Event.EventType.NodeCreated: await zooKeeper.getChildrenAsync(_path, await getWatcher); break; //子节点修改则继续监控子节点信息并通知客户端数据变更。 case Event.EventType.NodeChildrenChanged: try { var watcher = await getWatcher; var result = await zooKeeper.getChildrenAsync(_path, watcher); var childrens = result.Children.ToArray(); _action(_currentData, childrens); watcher.SetCurrentData(childrens); } catch (KeeperException.NoNodeException) { _action(_currentData, new string[0]); } break; //删除之后开始监控自身节点，并通知客户端数据被清空。 case Event.EventType.NodeDeleted: { var watcher = await getWatcher; await zooKeeper.existsAsync(_path, watcher); _action(_currentData, new string[0]); watcher.SetCurrentData(new string[0]); } break; } } #endregion Overrides of WatcherBase }
当前节点监听器：
internal class NodeMonitorWatcher : Watcher { private readonly Task<ZooKeeper> _zooKeeperCall; private readonly string _path; private readonly Action<byte[], byte[]> _action; private byte[] _currentData; public NodeMonitorWatcher(Task<ZooKeeper> zooKeeperCall, string path, Action<byte[], byte[]> action) { _zooKeeperCall = zooKeeperCall; _path = path; _action = action; } public NodeMonitorWatcher SetCurrentData(byte[] currentData) { _currentData = currentData; return this; } #region Overrides of WatcherBase public override async Task process(WatchedEvent watchedEvent) { switch (watchedEvent.get_Type()) { case Event.EventType.NodeDataChanged: var zooKeeper = await _zooKeeperCall; var watcher = new NodeMonitorWatcher(_zooKeeperCall, _path, _action); var data = await zooKeeper.getDataAsync(_path, watcher); var newData = data.Data; _action(_currentData, newData); watcher.SetCurrentData(newData); break; } } #endregion Overrides of WatcherBase }
连接断开监听器：
internal class ReconnectionWatcher : Watcher { private readonly Action _reconnection; public ReconnectionWatcher(Action reconnection) { _reconnection = reconnection; } #region Overrides of Watcher /// <summary>Processes the specified event.</summary> /// <param name="watchedEvent">The event.</param> /// <returns></returns> public override async Task process(WatchedEvent watchedEvent) { var state = watchedEvent.getState(); switch (state) { case Event.KeeperState.Expired: case Event.KeeperState.Disconnected: { _reconnection(); break; } } await Task.CompletedTask; } #endregion Overrides of Watcher }