BM-Bloggers

I have spent too long today trying to track down an intermittent “SQLite Error 5: ‘database is locked’” error in .Net Core Entity Framework.

I have read plenty of documentation and even tried swapping to use SQL Server, as opposed to SQLite, but this just resulted in the error ‘There is already an open DataReader associated with this Connection which must be closed first.’.

So everything pointed to it being a mistake I had made.

And it was, it turns out the issue was I had the dbContext.SaveChanges() call inside a foreach loop

It was

using (var dbContext = scope.ServiceProvider.GetRequiredService()) {
    var itemsToQueue = dbContext.CopyOperations.Where(o => o.RequestedStartTime < DateTime.UtcNow && o.Status == OperationStatus.Queued);
    foreach (var item in itemsToQueue) {
        item.Status = OperationStatus.StartRequested;
        item.StartTime = DateTime.UtcNow;
        dbContext.SaveChanges();
    }
}

And it should have been

 using (var dbContext = scope.ServiceProvider.GetRequiredService()) {
    var itemsToQueue = dbContext.CopyOperations.Where(o => o.RequestedStartTime < DateTime.UtcNow && o.Status == OperationStatus.Queued);
    foreach (var item in itemsToQueue) {
        item.Status = OperationStatus.StartRequested;
        item.StartTime = DateTime.UtcNow;
    }
    dbContext.SaveChanges();
}

Once this change was made my error disappeared.

There are good reasons why you might wish to move an existing Azure DevOps organisation from one region to another. The most common ones are probably:

• A new Azure DevOps region has become available since you created your organisation that is a ‘better home’ for your projects.
• New or changing national regulations require your source stored in a specific location.
• You want your repositories as close to your workers as possible, to reduce network latency.

One of these reasons meant I recently had to move an Azure DevOps organisation, so followed the documented process. This requires you to

1. Whilst logged in as the Azure DevOps organisation owner, open the Azure DevOps Virtual Support Agent
2. Select the quick action ‘Change Organization Region’
3. Follow the wizard to pick the new region and the date for the move.

You are warned that there could be a short loss of service during the move. Much of the move is done as a background process. It is only the final switch over that can interrupt service, hence this interruption being short.

I followed this process, but after the planned move date I found my organisation has not moved. In the Virtual Support Agent, I found the message.

Please note that region move requests are currently delayed due to ongoing deployments. We may not be able to perform the change at your requested time and may ask you to reschedule. We apologize for the potential delay and appreciate your patience!

I received no other emails, I suspect overly aggressive spam filters were the cause of that, but it meant I was unclear what to do next. Should I:

1. Just wait i.e. do not reschedule anything, even though the target date is now in the past
2. Reschedule the existing move request to a date in the future using the virtual assistant wizard
3. Cancel the old request and start the process again from scratch

After asking the question in the Visual Studio Developer Community Forums I was told the correct action is to cancel the old request and request a new move date. It seems that once your requested date is passed the move will not take place no matter how long you wait.

Hence, I created a new request, which all went through exactly as planned.

I was reminded recently of the hoops you have to jump through to run UWP unit tests within an Azure DevOps automated build.

The key steps you need to remember are as follows

Desktop Interaction

The build agent should not be running as a service it must be able to interact with the desktop.

If you did not set this mode during configuration this post from Donovan Brown shows how to swap the agent over without a complete reconfiguration.

Test Assemblies

The UWP unit test projects are not built as a DLL, but as an EXE.

I stupidly just made my VSTest task look for the generated EXE and run the tests they contained. This does not work generating the somewhat confusing error

Test run will use DLL(s) built for framework .NETFramework,Version=v4.0 and platform X86. Following DLL(s) do not match framework/platform settings.
BlackMarble.Spectrum.FridgeManagement.Client.OneWire.UnitTests.exe is built for Framework .NETCore,Version=v5.0 and Platform X86.

What you should search for as the entry point for the tests is the .appxrecipe file. Once tI used this my tests ran.

So my pipeline YML to run all the tests in a built solutions was

- task: VisualStudioTestPlatformInstaller@1
   inputs:
      packageFeedSelector: 'nugetOrg'
      versionSelector: 'latestPreRelease'              

- task: VSTest@2
    displayName: 'VSTest - testAssemblies'
    inputs:
       platform: 'x86'
       configuration: '$(BuildConfiguration)'
       testSelector: 'testAssemblies' 
testAssemblyVer2: | # Required when testSelector == TestAssemblies
         ***unittests.dll
        ***unittests.build.appxrecipe
         !***TestAdapter.dll
         !**obj** 
       searchFolder: '$(Build.SourcesDirectory)/src'
       resultsFolder: '$(System.DefaultWorkingDirectory)TestResults'
       runInParallel: false
       codeCoverageEnabled: true
       rerunFailedTests: false
       runTestsInIsolation: true
       runOnlyImpactedTests: false
        
- task: PublishTestResults@2
   displayName: 'Publish Test Results **/TEST-*.xml'
  condition: always()