Updated HelloWorld C# sample to the latest 6.0 version #4643 (#4648)

* Updated HelloWorld C# sample to the latest 6.0 version #4643

* Fixed a lint problem

* Updated README.md with .NET 6 instructions for #4643

code-samples/serving/hello-world/helloworld-csharp/Dockerfile

@@ -1,24 +1,19 @@
 # Use Microsoft's official build .NET image.
-FROM mcr.microsoft.com/dotnet/core/sdk:3.1 AS build
+FROM mcr.microsoft.com/dotnet/sdk:6.0 AS build-env
 WORKDIR /app
 
-# Install production dependencies.
-# Copy csproj and restore as distinct layers.
+# Copy csproj and restore as distinct layers
 COPY *.csproj ./
 RUN dotnet restore
 
-# Copy local code to the container image.
+# Copy everything else and build
 COPY . ./
-WORKDIR /app
-
-# Build a release artifact.
 RUN dotnet publish -c Release -o out
 
-
-# Use Microsoft's official runtime .NET image.
-FROM mcr.microsoft.com/dotnet/core/aspnet:3.1 AS runtime
+# Build runtime image
+FROM mcr.microsoft.com/dotnet/aspnet:6.0
 WORKDIR /app
-COPY --from=build /app/out ./
+COPY --from=build-env /app/out .
 
 # Run the web service on container startup.
 ENTRYPOINT ["dotnet", "helloworld-csharp.dll"]

code-samples/serving/hello-world/helloworld-csharp/Program.cs

@@ -1,26 +1,11 @@
-using System;
-using Microsoft.AspNetCore.Hosting;
-using Microsoft.Extensions.Hosting;
+var builder = WebApplication.CreateBuilder(args);
 
-namespace helloworld_csharp
-{
-    public class Program
-    {
-        public static void Main(string[] args)
-        {
-            CreateHostBuilder(args).Build().Run();
-        }
+var port = Environment.GetEnvironmentVariable("PORT") ?? "8080";
+var url = $"http://0.0.0.0:{port}";
+var target = Environment.GetEnvironmentVariable("TARGET") ?? "World";
 
-        public static IHostBuilder CreateHostBuilder(string[] args)
-        {
-            string port = Environment.GetEnvironmentVariable("PORT") ?? "8080";
-            string url = String.Concat("http://0.0.0.0:", port);
+var app = builder.Build();
 
-            return Host.CreateDefaultBuilder(args)
-                .ConfigureWebHostDefaults(webBuilder =>
-                {
-                    webBuilder.UseStartup<Startup>().UseUrls(url);
-                });
-        }
-    }
-}
+app.MapGet("/", () => $"Hello {target}!");
+
+app.Run(url);

code-samples/serving/hello-world/helloworld-csharp/Properties/launchSettings.json

@@ -1,27 +0,0 @@
-{
-  "iisSettings": {
-    "windowsAuthentication": false,
-    "anonymousAuthentication": true,
-    "iisExpress": {
-      "applicationUrl": "http://localhost:39053",
-      "sslPort": 44372
-    }
-  },
-  "profiles": {
-    "IIS Express": {
-      "commandName": "IISExpress",
-      "launchBrowser": true,
-      "environmentVariables": {
-        "ASPNETCORE_ENVIRONMENT": "Development"
-      }
-    },
-    "helloworld_csharp": {
-      "commandName": "Project",
-      "launchBrowser": true,
-      "applicationUrl": "https://localhost:5001;http://localhost:5000",
-      "environmentVariables": {
-        "ASPNETCORE_ENVIRONMENT": "Development"
-      }
-    }
-  }
-}

code-samples/serving/hello-world/helloworld-csharp/README.md

@@ -1,6 +1,6 @@
 # Hello world - .NET Core
 
-A simple web app written in C# using .NET Core 3.1 that you can use for testing.
+A simple web app written in C# using .NET 6.0 that you can use for testing.
 It reads in an env variable `TARGET` and prints "Hello \${TARGET}!". If TARGET
 is not specified, it will use "World" as the TARGET.
 
@@ -19,16 +19,16 @@ cd knative-docs/code-samples/serving/hello-world/helloworld-csharp
   [Install Knative Serving](https://knative.dev/docs/install/serving/install-serving-with-yaml).
 - [Docker](https://www.docker.com) installed and running on your local machine,
   and a Docker Hub account configured (we'll use it for a container registry).
-- You have installed [.NET Core SDK 3.1](https://www.microsoft.com/net/core).
+- You have installed [.NET Core SDK 6.0](https://www.microsoft.com/net/).
 
 ## Recreating the sample code
 
 1. First, make sure you have
-   [.NET Core SDK 3.1](https://www.microsoft.com/net/core) installed:
+   [.NET SDK 6.0](https://www.microsoft.com/net/) installed:
 
    ```bash
    dotnet --version
-   3.1.100
+   6.0.101
    ```
 
 1. From the console, create a new empty web project using the dotnet command:
@@ -37,35 +37,21 @@ cd knative-docs/code-samples/serving/hello-world/helloworld-csharp
    dotnet new web -o helloworld-csharp
    ```
 
-1. Update the `CreateHostBuilder` definition in `Program.cs` by adding
-   `.UseUrls()` to define the serving port:
+1. Update the `Program.cs` to read the port and define the serving url:
 
    ```csharp
-   public static IHostBuilder CreateHostBuilder(string[] args)
-   {
-       string port = Environment.GetEnvironmentVariable("PORT") ?? "8080";
-       string url = String.Concat("http://0.0.0.0:", port);
+   var port = Environment.GetEnvironmentVariable("PORT") ?? "8080";
+   var url = $"http://0.0.0.0:{port}";
 
-      return Host.CreateDefaultBuilder(args)
-          .ConfigureWebHostDefaults(webBuilder =>
-          {
-              webBuilder.UseStartup<Startup>().UseUrls(url);
-          });
-   }
+   app.Run(url);
    ```
 
-1. Update the `app.UseEndpoints(...)` statement in `Startup.cs` to read and return the
-   TARGET environment variable:
+1. Update the `Program.cs` to read and return the `TARGET` environment variable:
 
    ```csharp
-   app.UseEndpoints(endpoints =>
-   {
-      endpoints.MapGet("/", async context =>
-      {
-          var target = Environment.GetEnvironmentVariable("TARGET") ?? "World";
-          await context.Response.WriteAsync($"Hello {target}!\n");
-      });
-   });
+   var target = Environment.GetEnvironmentVariable("TARGET") ?? "World";
+
+   app.MapGet("/", () => $"Hello {target}!");
    ```
 
 1. In your project directory, create a file named `Dockerfile` and copy the following code
@@ -75,25 +61,21 @@ cd knative-docs/code-samples/serving/hello-world/helloworld-csharp
 
    ```docker
    # Use Microsoft's official build .NET image.
-   FROM mcr.microsoft.com/dotnet/core/sdk:3.1 AS build
+   FROM mcr.microsoft.com/dotnet/sdk:6.0 AS build-env
    WORKDIR /app
 
-   # Install production dependencies.
-   # Copy csproj and restore as distinct layers.
+   # Copy csproj and restore as distinct layers
    COPY *.csproj ./
    RUN dotnet restore
 
-   # Copy local code to the container image.
+   # Copy everything else and build
    COPY . ./
-   WORKDIR /app
-
-   # Build a release artifact.
    RUN dotnet publish -c Release -o out
 
-   # Use Microsoft's official runtime .NET image.
-   FROM mcr.microsoft.com/dotnet/core/aspnet:3.1 AS runtime
+   # Build runtime image
+   FROM mcr.microsoft.com/dotnet/aspnet:6.0
    WORKDIR /app
-   COPY --from=build /app/out ./
+   COPY --from=build-env /app/out .
 
    # Run the web service on container startup.
    ENTRYPOINT ["dotnet", "helloworld-csharp.dll"]

code-samples/serving/hello-world/helloworld-csharp/Startup.cs

@@ -1,38 +0,0 @@
-using System;
-using Microsoft.AspNetCore.Builder;
-using Microsoft.AspNetCore.Hosting;
-using Microsoft.AspNetCore.Http;
-using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.Hosting;
-
-namespace helloworld_csharp
-{
-    public class Startup
-    {
-        // This method gets called by the runtime. Use this method to add services to the container.
-        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
-        public void ConfigureServices(IServiceCollection services)
-        {
-        }
-
-        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
-        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
-        {
-            if (env.IsDevelopment())
-            {
-                app.UseDeveloperExceptionPage();
-            }
-
-            app.UseRouting();
-
-            app.UseEndpoints(endpoints =>
-            {
-                endpoints.MapGet("/", async context =>
-                {
-                    var target = Environment.GetEnvironmentVariable("TARGET") ?? "World";
-                    await context.Response.WriteAsync($"Hello {target}!\n");
-                });
-            });
-        }
-    }
-}

code-samples/serving/hello-world/helloworld-csharp/helloworld-csharp.csproj

@@ -1,8 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
-    <RootNamespace>helloworld_csharp</RootNamespace>
+    <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
   </PropertyGroup>
 
 </Project>