Initial commit

Dockerfile

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+#See https://aka.ms/containerfastmode to understand how Visual Studio uses this Dockerfile to build your images for faster debugging.
+
+FROM mcr.microsoft.com/dotnet/aspnet:6.0 AS base
+WORKDIR /app
+EXPOSE 80
+
+FROM mcr.microsoft.com/dotnet/sdk:6.0 AS build
+WORKDIR /src
+COPY ["StickySessionHelperExample/StickySessionHelperExample.csproj", "StickySessionHelperExample/"]
+RUN dotnet restore "StickySessionHelperExample/StickySessionHelperExample.csproj"
+COPY . .
+WORKDIR "/src/StickySessionHelperExample"
+RUN dotnet build "StickySessionHelperExample.csproj" -c Release -o /app/build
+
+FROM build AS publish
+RUN dotnet publish "StickySessionHelperExample.csproj" -c Release -o /app/publish
+
+FROM base AS final
+WORKDIR /app
+COPY --from=publish /app/publish .
+ENTRYPOINT ["dotnet", "StickySessionHelperExample.dll"]

StickySessionHelperExample.sln

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+
+Microsoft Visual Studio Solution File, Format Version 12.00
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "StickySessionHelperExample", "StickySessionHelperExample\StickySessionHelperExample.csproj", "{52E90663-FD00-4800-94A2-04879DEA6731}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{52E90663-FD00-4800-94A2-04879DEA6731}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{52E90663-FD00-4800-94A2-04879DEA6731}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{52E90663-FD00-4800-94A2-04879DEA6731}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{52E90663-FD00-4800-94A2-04879DEA6731}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+EndGlobal

StickySessionHelperExample/PodWatcher.cs

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+using System;
+using System.Collections;
+using System.Threading;
+using System.Threading.Tasks;
+using k8s;
+using k8s.Models;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Hosting;
+
+namespace StickySessionHelperExample;
+
+public class PodWatcher : BackgroundService
+{
+    // thread safe list
+    public static ArrayList IpAdresses = ArrayList.Synchronized(new ArrayList());
+    private readonly IConfiguration _configuration;
+
+    public PodWatcher(IConfiguration configuration)
+    {
+        _configuration = configuration;
+    }
+    
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        var inCluster = _configuration.GetValue("IN_CLUSTER", false);
+
+        var config = inCluster
+            ? KubernetesClientConfiguration.InClusterConfig()
+            : KubernetesClientConfiguration.BuildConfigFromConfigFile();
+
+        IKubernetes client = new Kubernetes(config);
+
+        var kubernetesNamespace = _configuration.GetValue("K8S_NAMESPACE_TO_WATCH", "default");
+
+        var podlistResp = client.CoreV1.ListNamespacedPodWithHttpMessagesAsync(kubernetesNamespace, watch: true, cancellationToken: stoppingToken);
+        await foreach (var (type, item) in podlistResp.WatchAsync<V1Pod, V1PodList>().WithCancellation(stoppingToken))
+        {
+            Console.Write($"Event Pod {type} : {item.Metadata.Name} - {item.Status.Phase} - {item.Status.PodIP} [");
+            foreach (var (key, value) in item.Metadata.Labels)
+            {
+                Console.Write($"{key}: {value}, ");    
+            }
+            
+            Console.WriteLine("]");
+
+            switch (type)
+            {
+                case WatchEventType.Added:
+                    IpAdresses.Add(item.Status.PodIP);
+                    break;
+                case WatchEventType.Deleted:
+                case WatchEventType.Error:
+                    IpAdresses.Remove(item.Status.PodIP);
+                    break;
+            }
+        }
+    }
+}

StickySessionHelperExample/Program.cs

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+using System;
+using System.Diagnostics;
+using System.Net;
+using System.Net.Http;
+using StickySessionHelperExample;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection;
+using Yarp.ReverseProxy.Forwarder;
+
+var builder = WebApplication.CreateBuilder(args);
+builder.Services.AddHttpForwarder();
+builder.Services.AddHostedService<PodWatcher>();
+
+var httpClient = new HttpMessageInvoker(new SocketsHttpHandler
+{
+    UseProxy = false,
+    AllowAutoRedirect = false,
+    AutomaticDecompression = DecompressionMethods.None,
+    UseCookies = false,
+    ActivityHeadersPropagator = new ReverseProxyPropagator(DistributedContextPropagator.Current)
+});
+var transformer = HttpTransformer.Default;
+var requestConfig = new ForwarderRequestConfig { ActivityTimeout = TimeSpan.FromSeconds(100) };
+Random rnd = new Random();
+
+var app = builder.Build();
+app.UseRouting();
+app.UseEndpoints(endpoints => 
+    endpoints.Map("/{**catch-all}", handler: async (HttpContext httpContext, IHttpForwarder forwarder) =>
+    {
+        var ipAddressNumber = rnd.Next(0, PodWatcher.IpAdresses.Count);
+        var ipAddress = PodWatcher.IpAdresses[ipAddressNumber] as string;
+        Console.WriteLine($"SEND CALL TO {ipAddress}");
+        
+        var error = await forwarder.SendAsync(httpContext, $"http://{ipAddress}/",
+            httpClient, requestConfig, transformer);
+        // Check if the operation was successful
+        if (error != ForwarderError.None)
+        {
+            var errorFeature = httpContext.GetForwarderErrorFeature();
+            var exception = errorFeature.Exception;
+        }
+    })
+);
+
+app.Run();

StickySessionHelperExample/Properties/launchSettings.json

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+{
+  "profiles": {
+    "StickySessionHelperExample": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": false,
+      "applicationUrl": "https://localhost:7018;http://localhost:5018",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}

StickySessionHelperExample/StickySessionHelperExample.csproj

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+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+    <PropertyGroup>
+        <TargetFramework>net6.0</TargetFramework>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <PackageReference Include="KubernetesClient" Version="8.0.4" />
+      <PackageReference Include="Yarp.ReverseProxy" Version="1.1.0" />
+    </ItemGroup>
+
+</Project>

StickySessionHelperExample/appsettings.Development.json

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+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  }
+}

StickySessionHelperExample/appsettings.json

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+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  },
+  "AllowedHosts": "*"
+}