Add microservices scaffold

DorkNet.Gateway/Program.cs

@@ -0,0 +1,68 @@
+using DorkNet.Contracts;
+using DorkNet.ServiceDefaults;
+using Microsoft.Extensions.Options;
+
+var builder = WebApplication.CreateBuilder(args);
+builder.Configuration.AddJsonFile("appsettings.Local.json",
+    optional: true, reloadOnChange: true);
+
+builder.AddDorkNetServiceDefaults(ServiceNames.Gateway);
+builder.Services.Configure<DorkNetServiceMapOptions>(
+    builder.Configuration.GetSection("DorkNet:Services"));
+
+var app = builder.Build();
+
+app.MapDorkNetServiceDefaults();
+
+app.MapGet("/", () => Results.Redirect("/healthz"));
+app.MapGet("/internal/services", (IOptions<DorkNetServiceMapOptions> options) =>
+    Results.Ok(options.Value.Endpoints()));
+
+app.MapGet("/internal/services/health", async (
+    IOptions<DorkNetServiceMapOptions> options,
+    IHttpClientFactory httpClientFactory,
+    CancellationToken ct) =>
+{
+    var client = httpClientFactory.CreateClient();
+    var probes = new List<ServiceProbeResponse>();
+
+    foreach (var endpoint in options.Value.Endpoints())
+    {
+        probes.Add(await ProbeServiceAsync(client, endpoint, ct));
+    }
+
+    return Results.Ok(probes);
+});
+
+app.Run();
+
+static async Task<ServiceProbeResponse> ProbeServiceAsync(
+    HttpClient client,
+    DorkNetServiceEndpoint endpoint,
+    CancellationToken ct)
+{
+    var checkedAt = DateTimeOffset.UtcNow;
+    var baseUrl = endpoint.BaseUrl.TrimEnd('/');
+
+    try
+    {
+        using var response = await client.GetAsync($"{baseUrl}/internal/healthz", ct);
+        return new ServiceProbeResponse(
+            endpoint.Name,
+            endpoint.BaseUrl,
+            response.IsSuccessStatusCode ? "ok" : "unhealthy",
+            (int)response.StatusCode,
+            null,
+            checkedAt);
+    }
+    catch (Exception ex) when (ex is HttpRequestException or TaskCanceledException)
+    {
+        return new ServiceProbeResponse(
+            endpoint.Name,
+            endpoint.BaseUrl,
+            "unreachable",
+            null,
+            ex.Message,
+            checkedAt);
+    }
+}