Initial exercise setup.

Additions

* Instructions for manually starting the database.
* Each phase now has a success criteria with how to verify.
* Troubleshooting section for working with the Docker DB container.
* All phases of the exercise are described in README.md (with as little advanced hints as possible).
* DFD to illustrate phase 1
* Debugging starts the database container and applies schema migrations (no setup required).
* Launch settings for VS Code, VS 2022 and Rider (IntelliJ IDEA).
* Swagger UI is available at <http://localhost:8080/swagger/index.html> for testing.

service/AppDbContext.cs

@@ -0,0 +1,10 @@
+using Microsoft.EntityFrameworkCore;
+
+namespace service;
+
+public class AppDbContext : DbContext
+{
+    public AppDbContext(DbContextOptions<AppDbContext> options) : base(options) { }
+
+    public DbSet<Post> Posts { get; set; }
+}

service/JsonPlaceholderClient.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Net.Http;
+using System.Net.Http.Json;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace service;
+
+public class JsonPlaceholderClient
+{
+    private readonly HttpClient _client;
+
+    public JsonPlaceholderClient(HttpClient client)
+    {
+        _client = client;
+        // TODO: Configure the client as needed.
+    }
+
+    public async Task<PostModel?> GetPostByIdAsync(int id, CancellationToken ct = default)
+    {
+        // TODO: Implement the logic to call the external service and retrieve the post by ID.
+        throw new NotImplementedException("This method will be implemented in Phase 1.");
+    }
+}

service/Post.cs

@@ -0,0 +1,27 @@
+using System;
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace service;
+
+[Table("posts")]
+public class Post
+{
+    [Key]
+    [Column("id")]
+    public int Id { get; set; }
+
+    [Column("user_id")]
+    public int UserId { get; set; }
+
+    [Column("title")]
+    [Required]
+    public string Title { get; set; }
+
+    [Column("body")]
+    [Required]
+    public string Body { get; set; }
+
+    [Column("updated_at")]
+    public DateTimeOffset UpdatedAt { get; set; } = DateTimeOffset.Parse("1970-01-01T00:00:00Z"); // TODO: Remove the default value in Phase 3.
+}

service/PostModel.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace service;
+
+[Serializable]
+public class PostModel
+{
+    public int Id { get; set; }
+    public int UserId { get; set; }
+    public string Title { get; set; }
+    public string Body { get; set; }
+}

service/Program.cs

@@ -0,0 +1,46 @@
+using System;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Polly.Simmy;
+
+using service;
+
+var builder = WebApplication.CreateBuilder(args);
+
+// Add services to the container.
+var services = builder.Services;
+services.AddRequestTimeouts();
+// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
+services.AddEndpointsApiExplorer();
+services.AddSwaggerGen();
+services.AddDbContext<AppDbContext>(optionsBuilder =>
+{
+    // Configure the database connection string.
+    var connectionString = builder.Configuration.GetValue<string>("PostgresConnection");
+    Console.WriteLine($"Connecting to PostgreSQL database with connection string: {connectionString}");
+    optionsBuilder.UseNpgsql(connectionString);
+});
+var httpClientBuilder = services.AddHttpClient<JsonPlaceholderClient>();
+
+var app = builder.Build();
+app.UseSwagger();
+app.UseSwaggerUI(); // Swagger UI is available at http://localhost:8080/swagger/index.html
+app.UseRequestTimeouts();
+
+app.MapGet("/posts/{id}", async (AppDbContext dbContext, JsonPlaceholderClient client, int id) =>
+{
+    // TODO: (Phase 1) Implement the logic to retrieve a post by ID and store it in the database.
+    // Consider some minimal error handling in case the post is not found (e.g. Id > 100).
+    return Results.Ok();
+})
+.WithRequestTimeout(TimeSpan.FromSeconds(29))
+.WithName("GetPostById")
+.WithOpenApi();
+
+app.Run();

service/Properties/launchSettings.json

@@ -0,0 +1,14 @@
+{
+  "profiles": {
+    "service": {
+      "commandName": "Project",
+      "launchBrowser": true,
+      "useSSL": false,
+      "launchUrl": "http://localhost:8080/swagger/index.html",
+      "applicationUrl": "http://localhost:8080/swagger/index.html",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      },
+    }
+  }
+}

service/appsettings.Docker.json

@@ -0,0 +1,3 @@
+{
+  "PostgresConnection": "Server=db;Database=mydatabase;User Id=user;Password=password;"
+}

service/appsettings.json

@@ -0,0 +1,11 @@
+{
+  "Urls": "http://0.0.0.0:8080",
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  },
+  "AllowedHosts": "*",
+  "PostgresConnection": "Server=localhost;Database=mydatabase;User Id=user;Password=password;"
+}

service/service.csproj

@@ -0,0 +1,20 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="8.0.16" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="9.0.6" />
+    <PackageReference Include="Microsoft.Extensions.Http.Resilience" Version="9.6.0" />
+    <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="9.0.4" />
+    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.6.2" />
+  </ItemGroup>
+
+  <Target Name="PostBuild" AfterTargets="PostBuildEvent">
+    <Exec Command="docker compose up -d db" />
+  </Target>
+
+</Project>