Refactor PolicyFactory and update SettlementDomainService

TransactionProcessor.BusinessLogic/Common/PolicyFactory.cs

@@ -14,51 +14,129 @@
 namespace TransactionProcessor.BusinessLogic.Common;
 
 [ExcludeFromCodeCoverage]
-public static class PolicyFactory{
-    public static IAsyncPolicy<Result> CreatePolicy(Int32 retryCount=5, TimeSpan? retryDelay = null, String policyTag="", Boolean withFallBack=false) {
-
-        TimeSpan retryDelayValue = retryDelay.GetValueOrDefault(TimeSpan.FromSeconds(2));
+public static class PolicyFactory
+{
+    private enum LogType
+    {
+        Retry,
+        Final
+    }
 
-        AsyncRetryPolicy<Result> retryPolicy = CreateRetryPolicy(retryCount, retryDelayValue, policyTag);
+    public static IAsyncPolicy<Result> CreatePolicy(
+        int retryCount = 5,
+        TimeSpan? retryDelay = null,
+        string policyTag = "",
+        bool withFallBack = false)
+    {
+        TimeSpan delay = retryDelay.GetValueOrDefault(TimeSpan.FromSeconds(5));
+        return CreateRetryPolicy(retryCount, delay, policyTag);
+    }
 
-        return retryPolicy;
+    public static IAsyncPolicy<Result<T>> CreatePolicy<T>(
+        int retryCount = 5,
+        TimeSpan? retryDelay = null,
+        string policyTag = "",
+        bool withFallBack = false)
+    {
+        TimeSpan delay = retryDelay.GetValueOrDefault(TimeSpan.FromSeconds(5));
+        return CreateRetryPolicy<T>(retryCount, delay, policyTag);
     }
 
-    public static async Task<Result> ExecuteWithPolicyAsync(Func<Task<Result>> action, IAsyncPolicy<Result> policy, String policyTag = "")
+    public static async Task<Result> ExecuteWithPolicyAsync(
+        Func<Task<Result>> action,
+        IAsyncPolicy<Result> policy,
+        string policyTag = "")
     {
         var context = new Context();
-        context["RetryCount"] = 0;
+        Result result = await policy.ExecuteAsync(ctx => action(), context);
 
-        Result result = await policy.ExecuteAsync((ctx) => action(), context);
-
-        int retryCount = (int)context["RetryCount"];
-        String message = result switch
-        {
-            { IsSuccess: true } => "Success",
-            { IsSuccess: false, Message: not "" } => result.Message,
-            { IsSuccess: false, Message: "", Errors: var errors } when errors.Any() => string.Join(", ", errors),
-            _ => "Unknown Error"
-        };
-        String retryMessage = retryCount > 0 ? $" after {retryCount} retries." : "";
-        // Log success if no retries were required
+        int retryCount = context.TryGetValue("RetryCount", out var retryObj) && retryObj is int r ? r : 0;
+        LogResult(policyTag, result, retryCount, LogType.Final);
 
-        Logger.LogWarning($"{policyTag} - {message} {retryMessage}");
+        return result;
+    }
+
+    public static async Task<Result<T>> ExecuteWithPolicyAsync<T>(
+        Func<Task<Result<T>>> action,
+        IAsyncPolicy<Result<T>> policy,
+        string policyTag = "")
+    {
+        var context = new Context();
+        Result<T> result = await policy.ExecuteAsync(ctx => action(), context);
+
+        int retryCount = context.TryGetValue("RetryCount", out var retryObj) && retryObj is int r ? r : 0;
+        LogResult(policyTag, result, retryCount, LogType.Final);
 
         return result;
     }
 
-    private static AsyncRetryPolicy<Result> CreateRetryPolicy(int retryCount, TimeSpan retryDelay, String policyTag)
+    private static AsyncRetryPolicy<Result> CreateRetryPolicy(
+        int retryCount,
+        TimeSpan retryDelay,
+        string policyTag)
     {
         return Policy<Result>
-            .HandleResult(result => !result.IsSuccess && String.Join("|",result.Errors).Contains("Append failed due to WrongExpectedVersion")) // Retry if the result is not successful
-            .OrResult(result => !result.IsSuccess && String.Join("|", result.Errors).Contains("DeadlineExceeded")) // Retry if the result is not successful
-            .WaitAndRetryAsync(retryCount,
-                _ => retryDelay, // Fixed delay
-                (result, timeSpan, retryCount, context) =>
+            .HandleResult(ShouldRetry)
+            .WaitAndRetryAsync(
+                retryCount,
+                _ => retryDelay,
+                (result, timeSpan, attempt, context) =>
+                {
+                    context["RetryCount"] = attempt;
+                    LogResult(policyTag, result.Result, attempt, LogType.Retry);
+                });
+    }
+
+    private static AsyncRetryPolicy<Result<T>> CreateRetryPolicy<T>(
+        int retryCount,
+        TimeSpan retryDelay,
+        string policyTag)
+    {
+        return Policy<Result<T>>
+            .HandleResult(ShouldRetry)
+            .WaitAndRetryAsync(
+                retryCount,
+                _ => retryDelay,
+                (result, timeSpan, attempt, context) =>
                 {
-                    context["RetryCount"] = retryCount;
-                    Logger.LogWarning($"{policyTag} - Retry {retryCount} due to unsuccessful result  {String.Join(".",result.Result.Errors)}. Waiting {timeSpan} before retrying...");
+                    context["RetryCount"] = attempt;
+                    LogResult(policyTag, result.Result, attempt, LogType.Retry);
                 });
+    }
+
+    private static bool ShouldRetry(ResultBase result)
+    {
+        return !result.IsSuccess && result.Errors.Any(e =>
+            e.Contains("WrongExpectedVersion", StringComparison.OrdinalIgnoreCase) ||
+            e.Contains("DeadlineExceeded", StringComparison.OrdinalIgnoreCase) ||
+            e.Contains("Cancelled"));
+    }
+
+    private static string FormatResultMessage(ResultBase result)
+    {
+        return result switch
+        {
+            { IsSuccess: true } => "Success",
+            { IsSuccess: false, Message: not "" } => result.Message,
+            { IsSuccess: false, Errors: var errors } when errors?.Any() == true => string.Join(", ", errors),
+            _ => "Unknown Error"
+        };
+    }
+
+    private static void LogResult(string policyTag, ResultBase result, int retryCount, LogType type)
+    {
+        string message = FormatResultMessage(result);
+
+        switch (type)
+        {
+            case LogType.Retry:
+                Logger.LogWarning($"{policyTag} - Retry {retryCount} due to error: {message}. Waiting before retrying...");
+                break;
 
+            case LogType.Final:
+                string retryMessage = retryCount > 0 ? $" after {retryCount} retries." : "";
+                Logger.LogWarning($"{policyTag} - {message}{retryMessage}");
+                break;
+        }
     }
-}
+}

TransactionProcessor.BusinessLogic/Services/SettlementDomainService.cs

@@ -7,17 +7,18 @@
 
 namespace TransactionProcessor.BusinessLogic.Services
 {
-    using System;
-    using System.Collections.Generic;
-    using System.Linq;
-    using System.Threading;
-    using System.Threading.Tasks;
     using Common;
     using Models;
+    using Polly;
     using Shared.DomainDrivenDesign.EventSourcing;
     using Shared.EventStore.Aggregate;
     using Shared.Exceptions;
     using Shared.Logger;
+    using System;
+    using System.Collections.Generic;
+    using System.Linq;
+    using System.Threading;
+    using System.Threading.Tasks;
 
     public interface ISettlementDomainService
     {
@@ -98,56 +99,53 @@
         // TODO: Add in a Get Settlement 
 
         public async Task<Result<Guid>> ProcessSettlement(SettlementCommands.ProcessSettlementCommand command,
-                                                              CancellationToken cancellationToken)
-        {
-            Guid settlementAggregateId = Helpers.CalculateSettlementAggregateId(command.SettlementDate, command.MerchantId,command.EstateId);
-            List<(Guid transactionId, Guid merchantId, CalculatedFee calculatedFee)> feesToBeSettled = new();
+                                                          CancellationToken cancellationToken) {
+            IAsyncPolicy<Result<Guid>> retryPolicy = PolicyFactory.CreatePolicy<Guid>(policyTag: "SettlementDomainService - ProcessSettlement");
+
+            return await PolicyFactory.ExecuteWithPolicyAsync<Guid>(async () => {
+                Guid settlementAggregateId = Helpers.CalculateSettlementAggregateId(command.SettlementDate, command.MerchantId, command.EstateId);
+                List<(Guid transactionId, Guid merchantId, CalculatedFee calculatedFee)> feesToBeSettled = new();
+
+                Result settlementResult = await ApplySettlementUpdates(async (SettlementAggregate settlementAggregate) => {
+                    if (settlementAggregate.IsCreated == false) {
+                        Logger.LogInformation($"No pending settlement for {command.SettlementDate:yyyy-MM-dd}");
+                        // Not pending settlement for this date
+                        return Result.Success();
+                    }
+
+                    Result<MerchantAggregate> getMerchantResult = await this.AggregateService.Get<MerchantAggregate>(command.MerchantId, cancellationToken);
+                    if (getMerchantResult.IsFailed)
+                        return ResultHelpers.CreateFailure(getMerchantResult);
+
+                    MerchantAggregate merchant = getMerchantResult.Data;
+                    if (merchant.SettlementSchedule == SettlementSchedule.Immediate) {
+                        // Mark the settlement as completed
+                        settlementAggregate.StartProcessing(DateTime.Now);
+                        settlementAggregate.ManuallyComplete();
+                        Result result = await this.AggregateService.Save(settlementAggregate, cancellationToken);
+                        return result;
+                    }
+
+                    feesToBeSettled = settlementAggregate.GetFeesToBeSettled();
+
+                    if (feesToBeSettled.Any()) {
+                        // Record the process call
+                        settlementAggregate.StartProcessing(DateTime.Now);
+                        return await this.AggregateService.Save(settlementAggregate, cancellationToken);
+                    }
 
-            Result settlementResult = await ApplySettlementUpdates(async (SettlementAggregate settlementAggregate) => {
-                if (settlementAggregate.IsCreated == false)
-                {
-                    Logger.LogInformation($"No pending settlement for {command.SettlementDate:yyyy-MM-dd}");
-                    // Not pending settlement for this date
                     return Result.Success();
-                }
 
-                Result<MerchantAggregate> getMerchantResult = await this.AggregateService.Get<MerchantAggregate>(command.MerchantId, cancellationToken);
-                if (getMerchantResult.IsFailed)
-                    return ResultHelpers.CreateFailure(getMerchantResult);
-
-                MerchantAggregate merchant = getMerchantResult.Data;
-                if (merchant.SettlementSchedule == SettlementSchedule.Immediate)
-                {
-                    // Mark the settlement as completed
-                    settlementAggregate.StartProcessing(DateTime.Now);
-                    settlementAggregate.ManuallyComplete();
-                    Result result = await this.AggregateService.Save(settlementAggregate, cancellationToken);
-                    return result;
-                }
+                }, settlementAggregateId, cancellationToken);
 
-                feesToBeSettled = settlementAggregate.GetFeesToBeSettled();
-
-                if (feesToBeSettled.Any())
-                {
-                    // Record the process call
-                    settlementAggregate.StartProcessing(DateTime.Now);
-                    return await this.AggregateService.Save(settlementAggregate, cancellationToken);
-                }
+                if (settlementResult.IsFailed)
+                    return settlementResult;
 
-                return Result.Success();
-
-            }, settlementAggregateId, cancellationToken);
-
-            if (settlementResult.IsFailed)
-                return settlementResult;
-
-            List<Result> failedResults = new();
-            foreach ((Guid transactionId, Guid merchantId, CalculatedFee calculatedFee) feeToSettle in feesToBeSettled) {
-                Result transactionResult = await ApplyTransactionUpdates(
-                    async (TransactionAggregate transactionAggregate) => {
+                List<Result> failedResults = new();
+                foreach ((Guid transactionId, Guid merchantId, CalculatedFee calculatedFee) feeToSettle in feesToBeSettled) {
+                    Result transactionResult = await ApplyTransactionUpdates(async (TransactionAggregate transactionAggregate) => {
                         try {
-                            transactionAggregate.AddSettledFee(feeToSettle.calculatedFee, command.SettlementDate,
-                                settlementAggregateId);
+                            transactionAggregate.AddSettledFee(feeToSettle.calculatedFee, command.SettlementDate, settlementAggregateId);
                             return Result.Success();
                         }
                         catch (Exception ex) {
@@ -156,15 +154,17 @@
                         }
                     }, feeToSettle.transactionId, cancellationToken);
 
-                if (transactionResult.IsFailed) {
-                    failedResults.Add(transactionResult);
+                    if (transactionResult.IsFailed) {
+                        failedResults.Add(transactionResult);
+                    }
                 }
-            }
 
-            if (failedResults.Any()) {
-                return Result.Failure($"Not all fees were processed successfully {failedResults.Count} have failed");
-            }
-            return Result.Success(settlementAggregateId);
+                if (failedResults.Any()) {
+                    return Result.Failure($"Not all fees were processed successfully {failedResults.Count} have failed");
+                }
+
+                return Result.Success(settlementAggregateId);
+            }, retryPolicy, "SettlementDomainService - ProcessSettlement");
         }
 
         public async Task<Result> AddMerchantFeePendingSettlement(SettlementCommands.AddMerchantFeePendingSettlementCommand command,