Implemented redlock for createPaymentIntent

Author: dLopes-SE

src/Common/Extensions/DependencyInjectionExtensions.cs

@@ -0,0 +1,22 @@
+using dotnet_qrshop.Common.Models;
+using RedLockNet;
+using RedLockNet.SERedis;
+using StackExchange.Redis;
+
+namespace dotnet_qrshop.Common.Extensions;
+
+public static class DependencyInjectionExtensions
+{
+  public static void AddRedisServices(this WebApplicationBuilder builder)
+  {
+    var configurationOptions = ConfigurationOptions.Parse(builder.Configuration.GetConnectionString("Redis") ?? "localhost:6379", true);
+    configurationOptions.AbortOnConnectFail = false;
+    configurationOptions.ConnectRetry = 3;
+
+    builder.Services.AddSingleton<IConnectionMultiplexer>(sp => ConnectionMultiplexer.Connect(configurationOptions));
+
+    builder.Services.Configure<RedlockSettings>(builder.Configuration.GetSection("Redlock"));
+    builder.Services.AddSingleton<IDistributedLockFactory, RedLockFactory>(_ =>
+      RedLockFactory.Create([ConnectionMultiplexer.Connect(configurationOptions)]));
+  }
+}

src/Common/Models/RedlockSettings.cs

@@ -0,0 +1,8 @@
+namespace dotnet_qrshop.Common.Models;
+
+public class RedlockSettings
+{
+  public TimeSpan Expiry { get; set; }
+  public TimeSpan Wait { get; set; }
+  public TimeSpan Retry { get; set; }
+}

src/Features/Payments/Commands/CancelPaymentIntent/CancelPaymentIntentEndpoint.cs

@@ -0,0 +1,29 @@
+using Carter;
+using dotnet_qrshop.Common.Models;
+using Microsoft.Extensions.Options;
+using RedLockNet;
+
+namespace dotnet_qrshop.Features.Payments.Commands.CancelPaymentIntent;
+
+public class CancelPaymentIntentEndpoint(
+  IDistributedLockFactory _lockFactory, 
+  IOptions<RedlockSettings> redlockOptions) : ICarterModule
+{
+  private readonly RedlockSettings _lockSettings = redlockOptions.Value;
+  public void AddRoutes(IEndpointRouteBuilder app)
+  {
+    app.MapGet("testredis", async () =>
+    {
+      using var redlock = await _lockFactory.CreateLockAsync("test", _lockSettings.Expiry, _lockSettings.Wait, _lockSettings.Retry);
+      if (redlock.IsAcquired)
+      {
+        Console.WriteLine("Acquired Lock - test Dylan");
+        await Task.Delay(10000);
+      }
+      else
+      {
+        Console.WriteLine("Didn't acquire lock");
+      }
+    });
+  }
+}

src/Features/Payments/Commands/CreatePaymentIntent/CreatePaymentIntentCommandHandler.cs

@@ -2,19 +2,32 @@
 using dotnet_qrshop.Abstractions.Authentication;
 using dotnet_qrshop.Abstractions.Messaging;
 using dotnet_qrshop.Common.Enums;
+using dotnet_qrshop.Common.Models;
 using dotnet_qrshop.Common.Results;
 using dotnet_qrshop.Infrastructure.Database.DbContext;
 using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Options;
+using RedLockNet;
 
 namespace dotnet_qrshop.Features.Payments.Commands.CreatePaymentIntent;
 
 public class CreatePaymentIntentCommandHandler(
   ApplicationDbContext _dbContext,
   IUserContext _userContext,
-  IPaymentService _paymentService) : ICommandHandler<CreatePaymentIntentCommand, string>
+  IPaymentService _paymentService,
+  IDistributedLockFactory _lockFactory,
+  IOptions<RedlockSettings> redlockOptions) : ICommandHandler<CreatePaymentIntentCommand, string>
 {
+  private readonly RedlockSettings _lockSettings = redlockOptions.Value;
   public async Task<Result<string>> Handle(CreatePaymentIntentCommand command, CancellationToken cancellationToken)
   {
+    using var redlock = await _lockFactory.CreateLockAsync("test", _lockSettings.Expiry, _lockSettings.Wait, _lockSettings.Retry);
+    if (!redlock.IsAcquired)
+    {
+      // TODO DYLAN: LOG here
+      return Result.Failure<string>(Error.Conflict("Couldn't create payment intent", "Error processing payment, please try again or contact the support"));
+    }
+
     var orderInfo = await _dbContext.Orders
       .AsNoTracking()
       .Where(o => o.UserId == _userContext.UserId && o.Id == command.OrderId)

src/Program.cs

@@ -3,6 +3,7 @@
 using dotnet_qrshop.Abstractions.Authentication;
 using dotnet_qrshop.Abstractions.Messaging;
 using dotnet_qrshop.Common.Behaviours;
+using dotnet_qrshop.Common.Extensions;
 using dotnet_qrshop.Common.Models.Identity;
 using dotnet_qrshop.Domains;
 using dotnet_qrshop.Features.Identity;
@@ -77,6 +78,9 @@
 // Authorization
 builder.Services.AddAuthorization();
 
+// Redis && Redlock
+builder.AddRedisServices();
+
 // Stripe
 StripeConfiguration.ApiKey = builder.Configuration["StripeApiKey"];
 
@@ -135,4 +139,6 @@
 
 app.MapCarter();
 
-app.Run();
+app.Run();
+
+

src/appsettings.json

@@ -5,6 +5,14 @@
       "Microsoft.AspNetCore": "Warning"
     }
   },
+  "Redis": {
+    "ConnectionString": ""
+  },
+  "Redlock": {
+    "Expiry": "00:00:30",
+    "Wait": "00:00:02",
+    "Retry":  "00:00:00.500"
+  },
   "AllowedHosts": "*",
   "ConnectionStrings": {
     "Database": "..."

src/dotnet-qrshop.csproj

@@ -83,7 +83,9 @@
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
     <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="9.0.4" />
+    <PackageReference Include="RedLock.net" Version="2.3.2" />
     <PackageReference Include="Scrutor" Version="6.0.1" />
+    <PackageReference Include="StackExchange.Redis" Version="2.9.32" />
     <PackageReference Include="Stripe.net" Version="49.0.0" />
     <PackageReference Include="Swashbuckle.AspNetCore" Version="8.1.1" />
     <PackageReference Include="System.Collections" Version="4.3.0" />