Consumer API: Starting multiple sync runs in parallel leads to an internal server error

[NikolaVetnic]

Readiness checklist

• I added/updated unit tests.
• I added/updated integration tests.
• I ensured that the PR title is good enough for the changelog.
• I labeled the PR.

Description

Due to the concurrency involved in the sync runs, the test results were not consistent between the runs. However, by setting the breakpoints at Backbone.Modules.Synchronization.Application.SyncRuns.Commands.StartSyncRun.Handler (lines 129 and 137) the relevant exception was caught and examined. The catch block was previously implemented like so:

        catch (DbUpdateException ex)
        {
            if (ex.HasReason(DbUpdateExceptionReason.DuplicateIndex))
                throw new OperationFailedException(ApplicationErrors.SyncRuns.CannotStartSyncRunWhenAnotherSyncRunIsRunning());

            throw;
        }

The problem with the tests was that some of the DbUpdateException instances were not being caught by the if check. Code examination of DbUpdateException yields the following condition:

            case DbUpdateExceptionReason.DuplicateIndex:
                return ex.Message.Contains("Index") || ex.InnerException != null && ex.InnerException.Message.Contains("UNIQUE");

Examination of the exception caught previously revealed the following values:

{
   "ex":{
      "Message":"An error occurred while saving the entity changes. See the inner exception for details.",
      "InnerException":{
         "Message":"23505: duplicate key value violates unique constraint 'IX_SyncRuns_CreatedBy_Index' \nDETAIL: Detail redacted as it may contain sensitive data. Specify 'Include Error Detail' in the connection string to include this information.",
         "SqlState":23505
      }
   }
}

In other words, no criteria defined for the DuplicateIndex variety of the DbUpdateExceptionReason was met. On the other hand, the exception matched the UniqueKeyViolation variety well:

            case DbUpdateExceptionReason.UniqueKeyViolation:
                return ex.GetBaseException() is SqlException { Number: 2627 } // SqlServer
                    or Npgsql.PostgresException { SqlState: "23505" };

For that reason the check in the catch block was updated as follows:

        catch (DbUpdateException ex)
        {
            if (ex.HasReason(DbUpdateExceptionReason.DuplicateIndex) || ex.HasReason(DbUpdateExceptionReason.UniqueKeyViolation))
                throw new OperationFailedException(ApplicationErrors.SyncRuns.CannotStartSyncRunWhenAnotherSyncRunIsRunning());

            throw;
        }

The tests now pass as expected.

Summary by CodeRabbit

• Bug Fixes
  • Improved error handling for synchronization processes by specifically addressing unique key violation scenarios.

[tnotheis]

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Walkthrough

The modification in the Handler.cs file within the synchronization application introduces an enhanced error handling mechanism. It specifically targets the scenario where a UniqueKeyViolation exception occurs, providing a more nuanced response to this particular error type during the synchronization run process.

Changes

File Path	Change Summary
.../SyncRuns/Commands/StartSyncRun/Handler.cs	Added handling for UniqueKeyViolation exception in CreateNewSyncRun method.

🐇✨
In the code where bytes dance and twirl,
A rabbit hops through the digital swirl.
With a tweak here and there, no error unfurled,
Making sync runs smoother in the virtual world.
🚀🐾

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Review Status

Actionable comments generated: 0

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Commits

Files that changed from the base of the PR and between 759679f and 14b589a.

Files selected for processing (1)

• Modules/Synchronization/src/Synchronization.Application/SyncRuns/Commands/StartSyncRun/Handler.cs (1 hunks)

Additional comments: 1

Modules/Synchronization/src/Synchronization.Application/SyncRuns/Commands/StartSyncRun/Handler.cs (1)

• 136-136: The update to the catch block in the CreateNewSyncRun method to include UniqueKeyViolation alongside DuplicateIndex when handling DbUpdateException is a crucial improvement. This change ensures that exceptions caused by unique constraint violations, which indicate an attempt to start a new sync run when another is already in progress, are properly caught and handled. This adjustment aligns with the PR's objective to enhance the reliability and consistency of synchronization operations by preventing multiple concurrent sync runs through improved error detection and handling.