API网关
API 网关一般放到微服务的最前端，并且要让API 网关变成由应用所发起的每个请求的入口。这样就可以明显的简化客户端实现和微服务应用程序之间的沟通方式。以前的话，客户端不得不去请求微服务A，然后再到微服务B，然后是微服务C。客户端需要去知道怎么去一起来消费这三个不同的service。使用API网关，我们可以抽象所有这些复杂性，并创建客户端们可以使用的优化后的端点，并向那些模块们发出请求。API网关的核心要点是：所有的客户端和消费端都通过统一的网关接入微服务，在网关层处理所有的非业务功能（比如验证、鉴权、监控、限流、请求合并...）
Ocelot
Ocelot是一个使用.NET Core平台上的一个API Gateway，这个项目的目标是在.NET上面运行微服务架构。它功能强大，包括了：路由、请求聚合、服务发现、认证、鉴权、限流熔断、并内置了负载均衡器与Service Fabric、Butterfly Tracing集成，还引入了Polly来进行故障处理。
Polly
Polly是一种.NET弹性和瞬态故障处理库，允许我们以非常顺畅和线程安全的方式来执诸如行重试，断路，超时，故障恢复等策略。
重试策略（Retry）
重试策略针对的前置条件是短暂的故障延迟且在短暂的延迟之后能够自我纠正。允许我们做的是能够自动配置重试机制。
断路器（Circuit-breaker）
断路器策略针对的前置条件是当系统繁忙时，快速响应失败总比让用户一直等待更好。保护系统故障免受过载，Polly可以帮其恢复。
超时（Timeout）
超时策略针对的前置条件是超过一定的等待时间，想要得到成功的结果是不可能的，保证调用者不必等待超时。
隔板隔离（Bulkhead Isolation）
隔板隔离针对的前置条件是当进程出现故障时，多个失败一直在主机中对资源（例如线程/ CPU）一直占用。下游系统故障也可能导致上游失败。这两个风险都将造成严重的后果。都说一粒老鼠子屎搅浑一锅粥，而Polly则将受管制的操作限制在固定的资源池中，免其他资源受其影响。
缓存（Cache）
缓存策略针对的前置条件是数据不会很频繁的进行更新，为了避免系统过载，首次加载数据时将响应数据进行缓存，如果缓存中存在则直接从缓存中读取。
回退（Fallback）
操作仍然会失败，也就是说当发生这样的事情时我们打算做什么。也就是说定义失败返回操作。
策略包装（PolicyWrap）
策略包装针对的前置条件是不同的故障需要不同的策略，也就意味着弹性灵活使用组合
Consul
Consul是HashiCorp公司推出的开源工具，用于实现分布式系统的服务发现与配置，内置了服务注册与发现框架、分布一致性协议实现、健康检查、Key/Value存储、多数据中心方案、在Ocelot已经支持简单的负载功能，也就是当下游服务存在多个结点的时候，Ocelot能够承担起负载均衡的作用。但是它不提供健康检查，服务的注册也只能通过手动在配置文件里面添加完成。这不够灵活并且在一定程度下会有风险。这个时候我们就可以用Consul来做服务发现并实现健康检查。
微服务搭建
一、设计思路
二、安装consul服务
文件结构信息
data
conf
consul.exe
配置conf.json信息 并运行 ：consul agent -config-dir="E:/PersonCode/.Net Core/consul/conf/conf.json"
{
"datacenter": "wf",
"data_dir": "E:/PersonCode/.Net Core/consul/data",
"log_level": "INFO",
"server": true,
"ui": true,
"bind_addr": "192.168.14.8",
"client_addr": "127.0.0.1",
"advertise_addr": "192.168.14.8",
"bootstrap_expect": 1,
"ports":{
"http": 8500,
"dns": 8600,
"server": 8300,
"serf_lan": 8301,
"serf_wan": 8302
}
}
运行结果：
三、创建多个API服务 并注册consul
1、创建 api项目 添加swagger Ui
2、引用Consul-1.6.1.1版本
3、添加Consul 服务配置
"Consul": {
"ServiceName": "Zfkr.WF.Core.API",
"ServiceIP": "localhost",
"ConsulClientUrl": "http://localhost:8500",
"HealthCheckRelativeUrl": "/wf/Base/health",
"HealthCheckIntervalInSecond": 5
}
4、添加Consul 服务注册类（RegisterCansulExtension）
5、添加服务注册与中间件
6、启用api 多个服务
dotnet Zfkr.WF.Core.API.dll --urls=http://*:8001
dotnet Zfkr.WF.Core.API.dll --urls=http://*:8002
dotnet Zfkr.WF.Core.API.dll --urls=http://*:8003
public static class RegisterCansulExtension
{
public static void RegisterToConsul(this IApplicationBuilder app, IConfiguration configuration, IHostApplicationLifetime lifetime)
{
lifetime.ApplicationStarted.Register(() =>
{
string serviceName = configuration.GetValue<string>("Consul:ServiceName");
string serviceIP = configuration.GetValue<string>("Consul:ServiceIP");
string consulClientUrl = configuration.GetValue<string>("Consul:ConsulClientUrl");
string healthCheckRelativeUrl = configuration.GetValue<string>("Consul:HealthCheckRelativeUrl");
int healthCheckIntervalInSecond = configuration.GetValue<int>("Consul:HealthCheckIntervalInSecond");
ICollection<string> listenUrls = app.ServerFeatures.Get<IServerAddressesFeature>().Addresses;
if (string.IsNullOrWhiteSpace(serviceName))
{
throw new Exception("Please use --serviceName=yourServiceName to set serviceName");
}
if (string.IsNullOrEmpty(consulClientUrl))
{
consulClientUrl = "http://127.0.0.1:8500";
}
if (string.IsNullOrWhiteSpace(healthCheckRelativeUrl))
{
healthCheckRelativeUrl = "health";
}
healthCheckRelativeUrl = healthCheckRelativeUrl.TrimStart('/');
if (healthCheckIntervalInSecond <= 0)
{
healthCheckIntervalInSecond = 1;
}
string protocol;
int servicePort = 0;
if (!TryGetServiceUrl(listenUrls, out protocol, ref serviceIP, out servicePort, out var errorMsg))
{
throw new Exception(errorMsg);
}
var consulClient = new ConsulClient(ConsulClientConfiguration => ConsulClientConfiguration.Address = new Uri(consulClientUrl));
var httpCheck = new AgentServiceCheck()
{
DeregisterCriticalServiceAfter = TimeSpan.FromSeconds(10),//服务启动多久后注册
Interval = TimeSpan.FromSeconds(healthCheckIntervalInSecond),
HTTP = $"{protocol}://{serviceIP}:{servicePort}/{healthCheckRelativeUrl}",
Timeout = TimeSpan.FromSeconds(2)
};
// 生成注册请求
var registration = new AgentServiceRegistration()
{
Checks = new[] { httpCheck },
ID = Guid.NewGuid().ToString(),
Name = serviceName,
Address = serviceIP,
Port = servicePort,
Meta = new Dictionary<string, string>() { ["Protocol"] = protocol },
Tags = new[] { $"{protocol}" }
};
consulClient.Agent.ServiceRegister(registration).Wait();
//服务停止时, 主动发出注销
lifetime.ApplicationStopping.Register(() =>
{
try
{
consulClient.Agent.ServiceDeregister(registration.ID).Wait();
}
catch
{ }
});
});
}
private static bool TryGetServiceUrl(ICollection<string> listenUrls, out string protocol, ref string serviceIP, out int port, out string errorMsg)
{
protocol = null;
port = 0;
errorMsg = null;
if (!string.IsNullOrWhiteSpace(serviceIP)) // 如果提供了对外服务的IP, 只需要检测是否在listenUrls里面即可
{
foreach (var listenUrl in listenUrls)
{
Uri uri = new Uri(listenUrl);
protocol = uri.Scheme;
var ipAddress = uri.Host;
port = uri.Port;
if (ipAddress == serviceIP || ipAddress == "0.0.0.0" || ipAddress == "[::]")
{
return true;
}
}
errorMsg = $"The serviceIP that you provide is not in urls={string.Join(',', listenUrls)}";
return false;
}
else // 没有提供对外服务的IP, 需要查找本机所有的可用IP, 看看有没有在 listenUrls 里面的
{
var allIPAddressOfCurrentMachine = System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces()
.Select(p => p.GetIPProperties())
.SelectMany(p => p.UnicastAddresses)
// 这里排除了 127.0.0.1 loopback 地址
.Where(p => p.Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork && !System.Net.IPAddress.IsLoopback(p.Address))
.Select(p => p.Address.ToString()).ToArray();
var uris = listenUrls.Select(listenUrl => new Uri(listenUrl)).ToArray();
// 本机所有可用IP与listenUrls进行匹配, 如果listenUrl是"0.0.0.0"或"[::]", 则任意IP都符合匹配
var matches = allIPAddressOfCurrentMachine.SelectMany(ip =>
uris.Where(uri => ip == uri.Host || uri.Host == "0.0.0.0" || uri.Host == "[::]")
.Select(uri => new { Protocol = uri.Scheme, ServiceIP = ip, Port = uri.Port })
).ToList();
if (matches.Count == 0)
{
errorMsg = $"This machine has IP address=[{string.Join(',', allIPAddressOfCurrentMachine)}], urls={string.Join(',', listenUrls)}, none match.";
return false;
}
else if (matches.Count == 1)
{
protocol = matches[0].Protocol;
serviceIP = matches[0].ServiceIP;
port = matches[0].Port;
return true;
}
else
{
errorMsg = $"Please use --serviceIP=yourChosenIP to specify one IP, which one provide service: {string.Join(",", matches)}.";
return false;
}
}
}
四、创建API网关
1、创建.core Api 项目 并引用相关包文件
Consul 1.6.11
Ocelot 16.0.1
Ocelot.Provider.Consul 16.0.1
2、添加ocelot.json文件 并配置
注意："ServiceName": "Zfkr.WF.Core.API", 服务名称必须与第三步中的 注册服务时的 服务名称一致，若未注册服务 可配置DownstreamHostAndPorts实现负载，之所以要使用Consul 是因为Ocelot自身 没有无法 实现健康检查 服务自动添加与移除
{
"Routes": [
/*Swagger 网关*/
{
"DownstreamPathTemplate": "/swagger/WorkFlow/swagger.json",
"DownstreamScheme": "http",
"DownstreamHostAndPorts": [
{
"Host": "localhost",
"Port": 8001
}
],
"LoadBalancer": "RoundRobin",
"UpstreamPathTemplate": "/WorkFlow/swagger/WorkFlow/swagger.json",
"UpstreamHttpMethod": [ "GET", "POST", "DELETE", "PUT" ]
},
//{
// "UseServiceDiscovery": true, // 使用服务发现
// "DownstreamPathTemplate": "/swagger/TaskSchedul/swagger.json",
// "DownstreamScheme": "http",
// "DownstreamHostAndPorts": [
// {
// "Host": "localhost",
// "Port": 8002
// }
// ],
// "LoadBalancer": "RoundRobin",
// "UpstreamPathTemplate": "/TaskSchedul/swagger/TaskSchedul/swagger.json",
// "UpstreamHttpMethod": [ "GET", "POST", "DELETE", "PUT" ]
//},
/*Api网关*/
{
"UseServiceDiscovery": true, //启用服务发现，若Ocelot集合Consul必须配置此项
"DownstreamPathTemplate": "/WF/{url}",
"DownstreamScheme": "http",
//"DownstreamHostAndPorts": [
// {
// "Host": "localhost",
// "Port": 8001
// },
// {
// "Host": "localhost",
// "Port": 8003
// }
//],
"UpstreamPathTemplate": "/WF/{url}",
"UpstreamHttpMethod": [ "Get", "Post" ],
"ServiceName": "Zfkr.WF.Core.API", //服务名称
"LoadBalancerOptions": {
"Type": "RoundRobin"
}
}
//,
//{
// "DownstreamPathTemplate": "/TS/{url}",
// "DownstreamScheme": "http",
// "DownstreamHostAndPorts": [
// {
// "Host": "localhost",
// "Port": 8002
// }
// ],
// "ServiceName": "node-2", // 服务名称
// "UseServiceDiscovery": true,
// "UpstreamPathTemplate": "/TS/{url}",
// "UpstreamHttpMethod": [ "Get", "Post" ],
// "LoadBalancerOptions": {
// "Type": "LeastConnection"
// }
//}
],
"GlobalConfiguration": {
"BaseUrl": "http://localhost:8899", //网关对外地址
"ReRouteIsCaseSensitive": false, //是否区分路由字母大小写
"ServiceDiscoveryProvider": { //服务发现提供者，配置Consul地址
"Host": "localhost", //Consul主机名称
"Port": 8500, //Consul端口号
"Type": "Consul" //必须指定Consul服务发现类型
}
//,
//"限流相关配置"
//"RateLimitOptions": {
// "ClientIdHeader": "ClientId",
// "QuotaExceededMessage": "RateLimit SCscHero", //限流响应提示
// "RateLimitCounterPrefix": "ocelot",
// "DisableRateLimitHeaders": false,
// "HttpStatusCode": 429
//}
}
}
3、添加Consul注册类 并注册到中间件，添加健康检查服务
3.1、添加appsettings 配置信息
"Consul": {
"ServiceName": "Gateway-9988-Service",
"Datacenter": "wf",
"ServiceIP": "localhost",
"ConsulClientUrl": "http://localhost:8500",
"HealthCheckRelativeUrl": "/wf/Base/health",
"HealthCheckIntervalInSecond": 5
}
3.2、添加Consul注册类
public static class RegisterCansulExtension
{
public static void RegisterToConsul(this IApplicationBuilder app, IConfiguration configuration, IHostApplicationLifetime lifetime)
{
lifetime.ApplicationStarted.Register(() =>
{
string serviceName = configuration.GetValue<string>("Consul:ServiceName");
string serviceIP = configuration.GetValue<string>("Consul:ServiceIP");
string consulClientUrl = configuration.GetValue<string>("Consul:ConsulClientUrl");
string healthCheckRelativeUrl = configuration.GetValue<string>("Consul:HealthCheckRelativeUrl");
int healthCheckIntervalInSecond = configuration.GetValue<int>("Consul:HealthCheckIntervalInSecond");
ICollection<string> listenUrls = app.ServerFeatures.Get<IServerAddressesFeature>().Addresses;
if (string.IsNullOrWhiteSpace(serviceName))
{
throw new Exception("Please use --serviceName=yourServiceName to set serviceName");
}
if (string.IsNullOrEmpty(consulClientUrl))
{
consulClientUrl = "http://127.0.0.1:8500";
}
if (string.IsNullOrWhiteSpace(healthCheckRelativeUrl))
{
healthCheckRelativeUrl = "health";
}
healthCheckRelativeUrl = healthCheckRelativeUrl.TrimStart('/');
if (healthCheckIntervalInSecond <= 0)
{
healthCheckIntervalInSecond = 1;
}
string protocol;
int servicePort = 0;
if (!TryGetServiceUrl(listenUrls, out protocol, ref serviceIP, out servicePort, out var errorMsg))
{
throw new Exception(errorMsg);
}
var consulClient = new ConsulClient(ConsulClientConfiguration => ConsulClientConfiguration.Address = new Uri(consulClientUrl));
var httpCheck = new AgentServiceCheck()
{
DeregisterCriticalServiceAfter = TimeSpan.FromSeconds(10),//服务启动多久后注册
Interval = TimeSpan.FromSeconds(healthCheckIntervalInSecond),
HTTP = $"{protocol}://{serviceIP}:{servicePort}/{healthCheckRelativeUrl}",
Timeout = TimeSpan.FromSeconds(2)
};
// 生成注册请求
var registration = new AgentServiceRegistration()
{
Checks = new[] { httpCheck },
ID = Guid.NewGuid().ToString(),
Name = serviceName,
Address = serviceIP,
Port = servicePort,
Meta = new Dictionary<string, string>() { ["Protocol"] = protocol },
Tags = new[] { $"{protocol}" }
};
consulClient.Agent.ServiceRegister(registration).Wait();
//服务停止时, 主动发出注销
lifetime.ApplicationStopping.Register(() =>
{
try
{
consulClient.Agent.ServiceDeregister(registration.ID).Wait();
}
catch
{ }
});
});
}
private static bool TryGetServiceUrl(ICollection<string> listenUrls, out string protocol, ref string serviceIP, out int port, out string errorMsg)
{
protocol = null;
port = 0;
errorMsg = null;
if (!string.IsNullOrWhiteSpace(serviceIP)) // 如果提供了对外服务的IP, 只需要检测是否在listenUrls里面即可
{
foreach (var listenUrl in listenUrls)
{
Uri uri = new Uri(listenUrl);
protocol = uri.Scheme;
var ipAddress = uri.Host;
port = uri.Port;
if (ipAddress == serviceIP || ipAddress == "0.0.0.0" || ipAddress == "[::]")
{
return true;
}
}
errorMsg = $"The serviceIP that you provide is not in urls={string.Join(',', listenUrls)}";
return false;
}
else // 没有提供对外服务的IP, 需要查找本机所有的可用IP, 看看有没有在 listenUrls 里面的
{
var allIPAddressOfCurrentMachine = System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces()
.Select(p => p.GetIPProperties())
.SelectMany(p => p.UnicastAddresses)
// 这里排除了 127.0.0.1 loopback 地址
.Where(p => p.Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork && !System.Net.IPAddress.IsLoopback(p.Address))
.Select(p => p.Address.ToString()).ToArray();
var uris = listenUrls.Select(listenUrl => new Uri(listenUrl)).ToArray();
// 本机所有可用IP与listenUrls进行匹配, 如果listenUrl是"0.0.0.0"或"[::]", 则任意IP都符合匹配
var matches = allIPAddressOfCurrentMachine.SelectMany(ip =>
uris.Where(uri => ip == uri.Host || uri.Host == "0.0.0.0" || uri.Host == "[::]")
.Select(uri => new { Protocol = uri.Scheme, ServiceIP = ip, Port = uri.Port })
).ToList();
if (matches.Count == 0)
{
errorMsg = $"This machine has IP address=[{string.Join(',', allIPAddressOfCurrentMachine)}], urls={string.Join(',', listenUrls)}, none match.";
return false;
}
else if (matches.Count == 1)
{
protocol = matches[0].Protocol;
serviceIP = matches[0].ServiceIP;
port = matches[0].Port;
return true;
}
else
{
errorMsg = $"Please use --serviceIP=yourChosenIP to specify one IP, which one provide service: {string.Join(",", matches)}.";
return false;
}
}
}
}
4、运行网关服务 dotnet Zfkr.WF.Core.Gateway.dll --urls=http://*:9988
