Guard /internal/refresh per game so a feed escape cannot 500 it

src/Lottery.Api/LotteryEndpoints.cs

@@ -145,7 +145,7 @@ await WithGameAsync(game, async g =>
         // Optionally guarded by a shared key: set Refresh:Key in the environment
         // (never in a committed file) and callers send X-Refresh-Key.
         app.MapPost("/internal/refresh", async (HttpRequest request, RefreshGame refresh,
-            IConfiguration configuration, CancellationToken ct) =>
+            IConfiguration configuration, ILoggerFactory loggerFactory, CancellationToken ct) =>
         {
             var requiredKey = configuration["Refresh:Key"];
             if (!string.IsNullOrEmpty(requiredKey)
@@ -154,9 +154,35 @@ await WithGameAsync(game, async g =>
                 return Results.Unauthorized();
             }
 
+            var logger = loggerFactory.CreateLogger("Lottery.Api.Refresh");
             var results = new List<RefreshResult>();
+
             foreach (var game in Enum.GetValues<Game>())
-                results.Add(await refresh.ExecuteAsync(game, ct));
+            {
+                try
+                {
+                    results.Add(await refresh.ExecuteAsync(game, ct));
+                }
+                // Per game rather than around the loop: one game's source
+                // failing must not cost the other game its refresh, which is
+                // what an unguarded loop did.
+                //
+                // RefreshGame reports the failure modes it anticipates. This
+                // catches the ones it does not, so a new escape degrades to a
+                // reported error instead of a 500 - and this is the endpoint
+                // the keep-alive workflow calls, so a 500 here reads as the
+                // whole instance being down.
+                //
+                // OperationCanceledException is deliberately excluded: a
+                // shutdown or a disconnected client is not a feed failure and
+                // must keep propagating.
+                catch (Exception ex) when (ex is not OperationCanceledException)
+                {
+                    logger.LogError(ex, "{Game}: refresh failed, reporting it as a feed error.", game);
+                    results.Add(new RefreshResult(game, UpToDate: false, NewDraws: 0,
+                        SkippedInvalid: 0, JackpotUpdated: false, FeedError: ex.Message));
+                }
+            }
 
             return Results.Ok(results.Select(r => new
             {

tests/Lottery.Api.Tests/RefreshEndpointTests.cs

@@ -1,7 +1,11 @@
 using System.Net;
 using System.Net.Http.Json;
 using System.Text.Json;
+using Lottery.Application.Abstractions;
+using Lottery.Domain;
 using Microsoft.AspNetCore.Hosting;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
 
 namespace Lottery.Api.Tests;
 
@@ -125,3 +129,64 @@ public async Task ARejectedCall_StillCarriesTheHardeningHeaders()
         Assert.Equal("nosniff", Assert.Single(response.Headers.GetValues("X-Content-Type-Options")));
     }
 }
+
+/// <summary>A numbers feed that throws a type RefreshGame's catch filter does not
+/// match, for the game named. Stands in for a future escape of the kind that took
+/// /internal/refresh to 500 twice.</summary>
+public sealed class ExplodingNumbersFeed : IWinningNumbersFeed
+{
+    public Task<IReadOnlyList<Draw>> GetDrawsAfterAsync(Game game, DateOnly after, CancellationToken ct) =>
+        game == Game.Powerball
+            ? throw new NotSupportedException("feed exploded")
+            : Task.FromResult<IReadOnlyList<Draw>>([]);
+}
+
+public sealed class ExplodingFeedFactory : LotteryApiFactory
+{
+    protected override void ConfigureWebHost(IWebHostBuilder builder)
+    {
+        base.ConfigureWebHost(builder);
+        builder.ConfigureServices(services =>
+        {
+            services.RemoveAll<IWinningNumbersFeed>();
+            services.AddSingleton<IWinningNumbersFeed, ExplodingNumbersFeed>();
+        });
+    }
+}
+
+public sealed class RefreshEndpointResilienceTests : IClassFixture<ExplodingFeedFactory>
+{
+    private readonly HttpClient _client;
+
+    public RefreshEndpointResilienceTests(ExplodingFeedFactory factory) => _client = factory.CreateClient();
+
+    [Fact]
+    public async Task AnUnanticipatedFeedFailure_IsReported_NotA500()
+    {
+        // Twice now a feed has thrown a type RefreshGame's filter did not match,
+        // and this endpoint - which the keep-alive workflow calls - answered 500,
+        // reading as the whole instance being down.
+        var response = await _client.PostAsync("/internal/refresh", null);
+
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+
+        var body = await response.Content.ReadFromJsonAsync<JsonElement>();
+        var powerball = body.EnumerateArray().Single(r => r.GetProperty("game").GetString() == "Powerball");
+        Assert.Contains("exploded", powerball.GetProperty("feedError").GetString());
+    }
+
+    [Fact]
+    public async Task OneGameFailing_DoesNotCostTheOtherItsRefresh()
+    {
+        // The loop used to abort on the first throw, so every game after the
+        // failing one was silently skipped.
+        var body = await (await _client.PostAsync("/internal/refresh", null))
+            .Content.ReadFromJsonAsync<JsonElement>();
+
+        var games = body.EnumerateArray().Select(r => r.GetProperty("game").GetString()!).ToArray();
+        Assert.Equal(["Powerball", "MegaMillions"], games);
+
+        var megaMillions = body.EnumerateArray().Single(r => r.GetProperty("game").GetString() == "MegaMillions");
+        Assert.Equal(JsonValueKind.Null, megaMillions.GetProperty("feedError").ValueKind);
+    }
+}