kubernetes provider (#772)

* feat: Kubernetes ServiceDiscoveryProvider

* 编写k8s测试例子

* feat：fix kube config

* feat： remove port

* feat ： complete the k8s test

* feat :  add kubeserviceDiscovery test

* feat : add kube provider unittest

* feat :add kubetnetes docs

how to use ocelot with kubetnetes docs

* keep the configuration as simple as possible, no qos, no cache

* fix: use http

* add PollingKubeServiceDiscovery

* feat : refactor logger

* feat : add  pollkube docs

* feat：Remove unnecessary code

* feat ： code-block json

src/Ocelot.Provider.Kubernetes/IKubeApiClientFactory.cs

@@ -0,0 +1,12 @@
+using KubeClient;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Ocelot.Provider.Kubernetes
+{
+    public interface IKubeApiClientFactory
+    {
+        IKubeApiClient Get(KubeRegistryConfiguration config);
+    }
+}

src/Ocelot.Provider.Kubernetes/KubeApiClientFactory.cs

@@ -0,0 +1,22 @@
+using KubeClient;
+
+namespace Ocelot.Provider.Kubernetes
+{
+    public class KubeApiClientFactory : IKubeApiClientFactory
+    {
+        public IKubeApiClient Get(KubeRegistryConfiguration config)
+        {
+            var option = new KubeClientOptions
+            {
+                ApiEndPoint = config.ApiEndPoint                
+            };
+            if(!string.IsNullOrEmpty(config?.AccessToken))
+            {
+                option.AccessToken = config.AccessToken;
+                option.AuthStrategy = config.AuthStrategy;
+                option.AllowInsecure = config.AllowInsecure;
+            }
+            return KubeApiClient.Create(option);
+        }
+    }
+}

src/Ocelot.Provider.Kubernetes/KubeProvider.cs

@@ -0,0 +1,63 @@
+using KubeClient;
+using KubeClient.Models;
+using Ocelot.Logging;
+using Ocelot.ServiceDiscovery.Providers;
+using Ocelot.Values;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Ocelot.Provider.Kubernetes
+{
+    public class Kube : IServiceDiscoveryProvider
+    {
+        private KubeRegistryConfiguration kubeRegistryConfiguration;
+        private IOcelotLogger logger;
+        private IKubeApiClient kubeApi;
+
+        public Kube(KubeRegistryConfiguration kubeRegistryConfiguration, IOcelotLoggerFactory factory, IKubeApiClientFactory kubeClientFactory)
+        {
+            this.kubeRegistryConfiguration = kubeRegistryConfiguration;
+            this.logger = factory.CreateLogger<Kube>();
+            this.kubeApi = kubeClientFactory.Get(kubeRegistryConfiguration);
+        }
+
+        public async Task<List<Service>> Get()
+        {
+            var service = await kubeApi.ServicesV1()
+                .Get(kubeRegistryConfiguration.KeyOfServiceInK8s, kubeRegistryConfiguration.KubeNamespace);
+            var services = new List<Service>();
+            if (IsValid(service))
+            {
+                services.Add(BuildService(service));
+            }
+            else
+            {
+                logger.LogWarning($"namespace:{kubeRegistryConfiguration.KubeNamespace }service:{kubeRegistryConfiguration.KeyOfServiceInK8s} Unable to use ,it is invalid. Address must contain host only e.g. localhost and port must be greater than 0");
+            }
+            return services;
+        }
+
+        private bool IsValid(ServiceV1 service)
+        {
+            if (string.IsNullOrEmpty(service.Spec.ClusterIP) || service.Spec.Ports.Count <= 0)
+            {
+                return false;
+            }
+
+            return true;
+        }
+
+        private Service BuildService(ServiceV1 serviceEntry)
+        {
+            var servicePort = serviceEntry.Spec.Ports.FirstOrDefault();
+            return new Service(
+                serviceEntry.Metadata.Name,
+                new ServiceHostAndPort(serviceEntry.Spec.ClusterIP, servicePort.Port),
+                serviceEntry.Metadata.Uid,
+                string.Empty,
+                Enumerable.Empty<string>());
+        }
+    }
+}

src/Ocelot.Provider.Kubernetes/KubeRegistryConfiguration.cs

@@ -0,0 +1,22 @@
+using KubeClient;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Ocelot.Provider.Kubernetes
+{
+    public class KubeRegistryConfiguration
+    {
+        public Uri ApiEndPoint { get; set; }
+
+        public string KubeNamespace { get; set; }
+
+        public string KeyOfServiceInK8s { get; set; }
+
+        public KubeAuthStrategy AuthStrategy { get; set; }
+
+        public string AccessToken { get; set; }
+
+        public bool AllowInsecure { get; set; }
+    }
+}

src/Ocelot.Provider.Kubernetes/KubernetesProviderFactory.cs

@@ -0,0 +1,38 @@
+using KubeClient;
+using Microsoft.Extensions.DependencyInjection;
+using Ocelot.Logging;
+using Ocelot.ServiceDiscovery;
+using System;
+
+namespace Ocelot.Provider.Kubernetes
+{
+    public static class KubernetesProviderFactory
+    {
+        public static ServiceDiscoveryFinderDelegate Get = (provider, config, name) =>
+        {
+            var factory = provider.GetService<IOcelotLoggerFactory>();             
+            return GetkubeProvider(provider, config, name, factory); 
+        };
+
+        private static ServiceDiscovery.Providers.IServiceDiscoveryProvider GetkubeProvider(IServiceProvider provider, Configuration.ServiceProviderConfiguration config, string name, IOcelotLoggerFactory factory)
+        {
+            var kubeClientFactory = provider.GetService<IKubeApiClientFactory>();
+            var k8sRegistryConfiguration = new KubeRegistryConfiguration()
+            {
+                ApiEndPoint = new Uri($"https://{config.Host}:{config.Port}"),
+                KeyOfServiceInK8s = name,
+                KubeNamespace = config.Namesapce,
+                AuthStrategy = KubeAuthStrategy.BearerToken,
+                AccessToken = config.Token,
+                AllowInsecure = true // Don't validate server certificate
+            };
+
+            var k8sServiceDiscoveryProvider = new Kube(k8sRegistryConfiguration, factory, kubeClientFactory);
+            if (config.Type?.ToLower() == "pollkube")
+            {
+                return new PollKube(config.PollingInterval, factory, k8sServiceDiscoveryProvider);
+            }
+            return k8sServiceDiscoveryProvider;
+        }
+    }
+}

src/Ocelot.Provider.Kubernetes/Ocelot.Provider.Kubernetes.csproj

@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="KubeClient" Version="2.2.4" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Ocelot\Ocelot.csproj" />
+  </ItemGroup>
+
+</Project>

src/Ocelot.Provider.Kubernetes/OcelotBuilderExtensions.cs

@@ -0,0 +1,15 @@
+using Microsoft.Extensions.DependencyInjection;
+using Ocelot.DependencyInjection;
+
+namespace Ocelot.Provider.Kubernetes
+{
+    public static class OcelotBuilderExtensions
+    {
+        public static IOcelotBuilder AddKubernetes(this IOcelotBuilder builder)
+        {
+            builder.Services.AddSingleton(KubernetesProviderFactory.Get);
+            builder.Services.AddSingleton<IKubeApiClientFactory, KubeApiClientFactory>();
+            return builder;
+        }
+    }
+}

src/Ocelot.Provider.Kubernetes/PollKube.cs

@@ -0,0 +1,50 @@
+using Ocelot.Logging;
+using Ocelot.ServiceDiscovery.Providers;
+using Ocelot.Values;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Ocelot.Provider.Kubernetes
+{
+    public class PollKube : IServiceDiscoveryProvider
+    {
+        private readonly IOcelotLogger _logger;
+        private readonly IServiceDiscoveryProvider _kubeServiceDiscoveryProvider;
+        private readonly Timer _timer;
+        private bool _polling;
+        private List<Service> _services;
+
+        public PollKube(int pollingInterval, IOcelotLoggerFactory factory, IServiceDiscoveryProvider kubeServiceDiscoveryProvider)
+        {
+            _logger = factory.CreateLogger<PollKube>();
+            _kubeServiceDiscoveryProvider = kubeServiceDiscoveryProvider;
+            _services = new List<Service>();
+
+            _timer = new Timer(async x =>
+            {
+                if (_polling)
+                {
+                    return;
+                }
+
+                _polling = true;
+                await Poll();
+                _polling = false;
+            }, null, pollingInterval, pollingInterval);
+        }
+
+        public Task<List<Service>> Get()
+        {
+            return Task.FromResult(_services);
+        }
+
+        private async Task Poll()
+        {
+            _services = await _kubeServiceDiscoveryProvider.Get();
+        }
+    }
+}
+ 

src/Ocelot/Configuration/Builder/ServiceProviderConfigurationBuilder.cs

@@ -8,6 +8,7 @@ namespace Ocelot.Configuration.Builder
         private string _token;
         private string _configurationKey;
         private int _pollingInterval;
+        private string _namespace;
 
         public ServiceProviderConfigurationBuilder WithHost(string serviceDiscoveryProviderHost)
         {
@@ -45,9 +46,15 @@ namespace Ocelot.Configuration.Builder
             return this;
         }
 
+        public ServiceProviderConfigurationBuilder WithNamesapce(string @namesapce)
+        {
+            _namespace = @namesapce;
+            return this;
+        }
+
         public ServiceProviderConfiguration Build()
         {
-            return new ServiceProviderConfiguration(_type, _serviceDiscoveryProviderHost, _serviceDiscoveryProviderPort, _token, _configurationKey, _pollingInterval);
+            return new ServiceProviderConfiguration(_type, _serviceDiscoveryProviderHost, _serviceDiscoveryProviderPort, _token, _configurationKey, _pollingInterval, _namespace);
         }
     }
 }

src/Ocelot/Configuration/Creator/ServiceProviderConfigurationCreator.cs

@@ -13,6 +13,7 @@ namespace Ocelot.Configuration.Creator
                 ? globalConfiguration?.ServiceDiscoveryProvider?.Type 
                 : "consul";
             var pollingInterval = globalConfiguration?.ServiceDiscoveryProvider?.PollingInterval ?? 0;
+            var k8snamesapce = globalConfiguration?.ServiceDiscoveryProvider?.Namespace ?? string.Empty;
 
             return new ServiceProviderConfigurationBuilder()
                 .WithHost(host)
@@ -21,6 +22,7 @@ namespace Ocelot.Configuration.Creator
                 .WithToken(globalConfiguration?.ServiceDiscoveryProvider?.Token)
                 .WithConfigurationKey(globalConfiguration?.ServiceDiscoveryProvider?.ConfigurationKey)
                 .WithPollingInterval(pollingInterval)
+                .WithNamesapce(k8snamesapce)
                 .Build();
         }
     }

src/Ocelot/Configuration/File/FileServiceDiscoveryProvider.cs

@@ -8,5 +8,6 @@ namespace Ocelot.Configuration.File
         public string Token { get; set; }
         public string ConfigurationKey { get; set; }
         public int PollingInterval { get; set; }
+        public string Namespace { get; set; }
     }
 }

src/Ocelot/Configuration/ServiceProviderConfiguration.cs

@@ -2,7 +2,7 @@
 {
     public class ServiceProviderConfiguration
     {
-        public ServiceProviderConfiguration(string type, string host, int port, string token, string configurationKey, int pollingInterval)
+        public ServiceProviderConfiguration(string type, string host, int port, string token, string configurationKey, int pollingInterval, string @namespace = "")
         {
             ConfigurationKey = configurationKey;
             Host = host;
@@ -10,13 +10,21 @@
             Token = token;
             Type = type;
             PollingInterval = pollingInterval;
+            Namesapce = @namespace;
         }
 
         public string Host { get; }
+
         public int Port { get; }
+
         public string Type { get; }
+
         public string Token { get; }
+
         public string ConfigurationKey { get; }
+
         public int PollingInterval { get; }
+
+        public string Namesapce { get; }
     }
 }