Scale unique answer tracking

api/QuestionsApi/Program.cs

@@ -3,16 +3,21 @@ using Microsoft.AspNetCore.Diagnostics;
 using Microsoft.IdentityModel.Tokens;
 using Microsoft.OpenApi.Models;
 using QuestionsApi.Services;
+using MongoDB.Bson;
 using System.Text;
 
 var builder = WebApplication.CreateBuilder(args);
 builder.Services.AddControllers();
 
+builder.Services.AddSingleton<MongoDatabaseProvider>();
 builder.Services.AddSingleton<QuestionStore>();
 builder.Services.AddSingleton<QuestionAttemptStore>();
+builder.Services.AddSingleton<AnswerStatisticsStore>();
 builder.Services.AddSingleton<RatingStore>();
 builder.Services.AddSingleton<QuestionMediaStore>();
 builder.Services.AddSingleton<QuestionReportStore>();
+builder.Services.AddSingleton<ServiceMetrics>();
+builder.Services.AddHostedService<AnswerStatisticsMaintenanceService>();
 
 builder.Services.AddEndpointsApiExplorer();
 builder.Services.AddSwaggerGen(c =>
@@ -61,6 +66,19 @@ builder.Services.AddAuthorization();
 
 var app = builder.Build();
 
+app.Use(async (context, next) =>
+{
+    var started = System.Diagnostics.Stopwatch.StartNew();
+    try
+    {
+        await next();
+    }
+    finally
+    {
+        context.RequestServices.GetRequiredService<ServiceMetrics>().HttpRequest(started.Elapsed);
+    }
+});
+
 app.UseExceptionHandler(errorApp =>
 {
     errorApp.Run(async context =>
@@ -96,6 +114,12 @@ app.UseExceptionHandler(errorApp =>
 });
 
 app.MapGet("/healthz", () => Results.Ok("ok"));
+app.MapGet("/readyz", async (MongoDatabaseProvider mongo) =>
+{
+    await mongo.Database.RunCommandAsync<BsonDocument>(new BsonDocument("ping", 1));
+    return Results.Ok("ready");
+});
+app.MapGet("/metrics", (ServiceMetrics metrics) => Results.Text(metrics.RenderPrometheus(), "text/plain; version=0.0.4"));
 app.UseSwagger();
 app.UseSwaggerUI(o =>
 {