feat: proper health-check for github

SS14.Labeller/HealthChecks/GitHubApiHealthCheck.cs

@@ -0,0 +1,56 @@
+using Microsoft.Extensions.Caching.Memory;
+using Microsoft.Extensions.Diagnostics.HealthChecks;
+using SS14.Labeller.GitHubApi;
+
+namespace SS14.Labeller.HealthChecks;
+
+public class GitHubApiKeyHealthCheck(IHttpClientFactory httpClientFactory, IMemoryCache cache) : IHealthCheck
+{
+    public async Task<HealthCheckResult> CheckHealthAsync(
+        HealthCheckContext context,
+        CancellationToken cancellationToken = default
+    )
+    {
+        var result = await cache.GetOrCreateAsync(
+            "GHKeyHealthCheck", 
+            async entry =>
+            {
+                entry.AbsoluteExpirationRelativeToNow = TimeSpan.FromSeconds(5);
+                return await CheckHealthAsyncInternal(cancellationToken);
+            }
+        );
+
+        return result;
+    }
+
+    private async Task<HealthCheckResult> CheckHealthAsyncInternal(CancellationToken cancellationToken)
+    {
+        try
+        {
+            var client = httpClientFactory.CreateClient(nameof(IGitHubApiClient));
+
+            // Make a simple, low-impact request to verify the key
+            var response = await client.GetAsync("https://api.github.com/user", cancellationToken);
+
+            if (response.IsSuccessStatusCode)
+            {
+                return HealthCheckResult.Healthy("GitHub API key is valid.");
+            }
+
+            if (response.StatusCode is System.Net.HttpStatusCode.Unauthorized or System.Net.HttpStatusCode.Forbidden)
+            {
+                return HealthCheckResult.Unhealthy("GitHub API key is invalid or lacks necessary permissions.");
+            }
+
+            return HealthCheckResult.Degraded($"GitHub API returned an unexpected status code: {response.StatusCode}");
+        }
+        catch (HttpRequestException ex)
+        {
+            return HealthCheckResult.Unhealthy("Failed to connect to GitHub API", exception: ex);
+        }
+        catch (Exception ex)
+        {
+            return HealthCheckResult.Unhealthy("An unexpected error occurred during GitHub API key health check", exception: ex);
+        }
+    }
+}

SS14.Labeller/Program.cs

@@ -1,11 +1,5 @@
 using Dapper;
-using Microsoft.AspNetCore.Mvc;
-using Microsoft.Extensions.Options;
-using SS14.Labeller.Configuration;
 using SS14.Labeller.Endpoints;
-using SS14.Labeller.Handlers;
-using SS14.Labeller.Middlewares;
-using SS14.Labeller.Models;
 
 [module:DapperAot]
 
@@ -31,6 +25,9 @@ public static void Main(string[] args)
         app.UseHttpLogging();
 
         app.MapGet("/", () => Results.Ok("Nik is a cat!"));
+
+        app.MapHealthChecks("/health");
+
         app.MapGithubWebhook();
 
         app.Run();

SS14.Labeller/Registry.cs

@@ -7,6 +7,7 @@
 using SS14.Labeller.Labelling;
 using SS14.Labeller.Repository;
 using System.Net.Http.Headers;
+using SS14.Labeller.HealthChecks;
 using Polly;
 using Polly.Extensions.Http;
 
@@ -80,6 +81,14 @@ public static void RegisterDependencies(this IServiceCollection service, IConfig
             sp => sp.GetServices<RequestHandlerBase>()
                     .ToDictionary(x => x.CanHandleType)
         );
+
+        service.AddHealthChecks()
+               .AddCheck<GitHubApiKeyHealthCheck>(
+                   "GitHub API Key",
+                   tags: ["github", "api-key"]
+                );
+
+        service.AddMemoryCache();
     }
 
     private static IAsyncPolicy<HttpResponseMessage> GetDiscourseRetryPolicy(IServiceProvider sp)