Ocelot網關

Ocelot是一個.net core框架下的網關的開源項目，下圖是官方給出的基礎實現圖，即把後臺的多個服務統一到網關處，前端應用：桌面端，web端，app端都只用訪問網關便可。

 

Ocelot的實現原理就是把客戶端對網關的請求(Request)，按照configuration.json的映射配置，轉發給對應的後端http service，而後從後端http service獲取響應(Response)後，再返回給客戶端。固然有了網關後，咱們能夠在網關這層去作統一驗證，也能夠在網關處統一做監控。

接下來作個Demo

新建三個asp.net core web aip項目：

OcelotGateway網關項目，端口是5000

DemoAAPI項目A，端口是5001

DemoBAPI項目B，端口是5002

(注：端口能夠在每一個項目的Properties下的launchSettings.json中修改，發佈後的端口能夠在Program.cs中用UseUrls(「http://*:5000」)來修改)

對於OcelotGateway：

引用Ocelot的Nuget包：

視圖->其餘窗口->程序包管理控制檯：Install-Package Ocelot

或項目右鍵「管理Nuget程序包」，在瀏覽裏查找Ocelot進行安裝

在OcelotGateway項目中添加一個configuration.json文件，關把它的屬性「複製到輸出目錄」，設成「始終複製」，內容以下：

{

  "ReRoutes": [

    {

      "DownstreamPathTemplate": "/demoaapi/values",

      "DownstreamScheme": "http",

      "DownstreamPort": 5001,

      "DownstreamHost": "localhost",

      "UpstreamPathTemplate": "/demoaapi/values",

      "UpstreamHttpMethod": [ "Get" ],

      "QoSOptions": {

        "ExceptionsAllowedBeforeBreaking": 3,

        "DurationOfBreak": 10,

        "TimeoutValue": 5000

      },

      "HttpHandlerOptions": {

        "AllowAutoRedirect": false,

        "UseCookieContainer": false

      },

      "AuthenticationOptions": {

        "AuthenticationProviderKey": "",

        "AllowedScopes": []

      }

    },

    {

      "DownstreamPathTemplate": "/demobapi/values",

      "DownstreamScheme": "http",

      "DownstreamPort": 5002,

      "DownstreamHost": "localhost",

      "UpstreamPathTemplate": "/demobapi/values",

      "UpstreamHttpMethod": [ "Get" ],

      "QoSOptions": {

        "ExceptionsAllowedBeforeBreaking": 3,

        "DurationOfBreak": 10,

        "TimeoutValue": 5000

      },

      "HttpHandlerOptions": {

        "AllowAutoRedirect": false,

        "UseCookieContainer": false

      },

      "AuthenticationOptions": {

        "AuthenticationProviderKey": "",

        "AllowedScopes": []

      }

    }

  ]

}

接下來對OcelotGateway的Program.cs進行改造 

 1 using Microsoft.AspNetCore.Hosting;
 2 
 3 using Microsoft.Extensions.Configuration;
 4 
 5 using Microsoft.Extensions.DependencyInjection;
 6 
 7  
 8 
 9 namespace OcelotGateway
10 
11 {
12 
13     public class Program
14 
15     {
16 
17         public static void Main(string[] args)
18 
19         {
20 
21             BuildWebHost(args).Run();
22 
23         }
24 
25         public static IWebHost BuildWebHost(string[] args)
26 
27         {
28 
29             IWebHostBuilder builder = new WebHostBuilder();
30 
31             //注入WebHostBuilder
32 
33             return builder.ConfigureServices(service =>
34 
35                 {
36 
37                     service.AddSingleton(builder);
38 
39                 })
40 
41                 //加載configuration配置文人年
42 
43                 .ConfigureAppConfiguration(conbuilder =>
44 
45                 {
46 
47                     conbuilder.AddJsonFile("configuration.json");
48 
49                 })
50 
51                 .UseKestrel()
52 
53                 .UseUrls("http://*:5000")
54 
55                 .UseStartup<Startup>()
56 
57                 .Build();
58 
59         }
60 
61     }
62 
63 }

View Code

同時，修改Startup.cs

 1 using Microsoft.AspNetCore.Builder;
 2 
 3 using Microsoft.AspNetCore.Hosting;
 4 
 5 using Microsoft.Extensions.Configuration;
 6 
 7 using Microsoft.Extensions.DependencyInjection;
 8 
 9 using Ocelot.DependencyInjection;
10 
11 using Ocelot.Middleware;
12 
13  
14 
15 namespace OcelotGateway
16 
17 {
18 
19     public class Startup
20 
21     {
22 
23         public Startup(IConfiguration configuration)
24 
25         {
26 
27             Configuration = configuration;
28 
29         }
30 
31         public IConfiguration Configuration { get; }     
32 
33         public void ConfigureServices(IServiceCollection services)
34 
35         {      
36 
37             //注入配置文件，AddOcelot要求參數是IConfigurationRoot類型，因此要做個轉換
38 
39             services.AddOcelot(Configuration as ConfigurationRoot);
40 
41         }
42 
43         public  void Configure(IApplicationBuilder app, IHostingEnvironment env)
44 
45         {
46 
47             //添加中間件
48 
49             app.UseOcelot().Wait();
50 
51         }
52 
53     }
54 
55 }

View Code

爲了測試數據好看，咱們把DemoAAPI項目和DemoBAPI項目的ValuesController做一下修改：    

 1 [Route("demoaapi/[controller]")]
 2 
 3     public class ValuesController : Controller
 4 
 5     {       
 6 
 7         [HttpGet]
 8 
 9         public IEnumerable<string> Get()
10 
11         {
12 
13             return new string[] { "DemoA服務", "請求" };
14 
15         }
16 
17 //……
18 
19 }
20 
21  
22 
23     [Route("demobapi/[controller]")]
24 
25     public class ValuesController : Controller
26 
27     {       
28 
29         [HttpGet]
30 
31         public IEnumerable<string> Get()
32 
33         {
34 
35             return new string[] { "DemoB服務", "請求" };
36 
37         }
38 
39 //……
40 
41 }

View Code

最後在解決方案屬性->多個啓動項目中，把DemoAAPI，DemoBAPI，OcelotGateway都設成啓動，開始啓動解決方案，效果以下圖 

 

《基於.net core微服務架構視頻》

 http://edu.51cto.com/course/13342.html