VS2013 publish Web deployment task failed The file is in use

I have found the reason why the solution at http://blogs.msdn.com/b/webdev/archive/2013/10/30/web-publishing-updates-for-app-offline-and-usechecksum.aspx did not work for the original poster, and I have a workaround.

The issue with the EnableMSDeployAppOffline approach is that it only recycles the app domain hosting the application. It does not recycle the app pool worker process (w3wp.exe) which the app domain lives in.

Tearing down and recreating the app domain will not affect the Sql Server Spatial dlls in question. Those dlls are unmanaged code which are manually loaded via interop LoadLibray calls. Therefore the dlls live outside the purview of the app domain.

In order to release the files locks, which the app pool process puts on them, you need to either recycle the app pool, or unload the dlls from memory manually.

The Microsoft.SqlServer.Types nuget package ships a class which is used to load the Spatial dlls called SqlServerTypes.Utilities. You can modify the LoadNativeAssemblies method to unload the unmanaged dlls when the app domain is unloaded. With this modification when msdeploy copys the app_offline.htm the app domain will unload and then unload the managed dlls as well.

[DllImport("kernel32.dll", SetLastError = true)]
internal extern static bool FreeLibrary(IntPtr hModule);

private static IntPtr _msvcrPtr = IntPtr.Zero;
private static IntPtr _spatialPtr = IntPtr.Zero;

public static void LoadNativeAssemblies(string rootApplicationPath)
{
    if (_msvcrPtr != IntPtr.Zero || _spatialPtr != IntPtr.Zero)
        throw new Exception("LoadNativeAssemblies already called.");

    var nativeBinaryPath = IntPtr.Size > 4
        ? Path.Combine(rootApplicationPath, @"SqlServerTypes\x64\")
        : Path.Combine(rootApplicationPath, @"SqlServerTypes\x86\");

    _msvcrPtr = LoadNativeAssembly(nativeBinaryPath, "msvcr100.dll");
    _spatialPtr = LoadNativeAssembly(nativeBinaryPath, "SqlServerSpatial110.dll");

    AppDomain.CurrentDomain.DomainUnload += (sender, e) =>
    {
        if (_msvcrPtr != IntPtr.Zero)
        {
            FreeLibrary(_msvcrPtr);
            _msvcrPtr = IntPtr.Zero;
        }

        if (_spatialPtr != IntPtr.Zero)
        {
            FreeLibrary(_spatialPtr);
            _spatialPtr = IntPtr.Zero;
         }
    };
}

There is one caveat with this approach. It assumes your application is the only one running in the worker process that is using the Spatial dlls. Since app pools can host multiple applications the file locks will not be released if another application has also loaded them. This will prevent your deploy from working with the same file locked error.

You can take you app offline during publishing which hopefully should free up the lock on the file and allow you to update it.

I blogged about this a while back. The support outlined was shipped inside of the Azure SDK and Visual Studio Update. I don't remember the exact releases but I can find out if needed. Any update dating around/after that blog post should be fine.

Prerequisites:

• VS 2012 + VS update / VS 2013 + VS Update / VS2015
• MSDeploy v3

Note: if you are publishing from a CI server the CI server will need the updates above as well

Edit the publish profile

In VS when create a Web Publish profile the settings from the dialog are stored in Properties\PublishProfiles\ as files that end with .pubxml. Note: there is also a .pubxml.user file, that file should not be modified

To take your app offline in the .pubxml file add the following property.

<EnableMSDeployAppOffline>true</EnableMSDeployAppOffline>

Notes

ASP.NET Required

The way that this has been implemented on the MSDeploy side is that an app_offline.htm file is dropped in the root of the website/app. From there the asp.net runtime will detect that and take your app offline. Because of this if your website/app doesn't have asp.net enabled this function will not work.

Cases where it may not work

The implementation of this makes it such that the app may not strictly be offline before publish starts. First the app_offline.htm file is dropped, then MSDeploy will start publishing the files. It doesn't wait for ASP.NET to detect the file and actually take it offline. Because of this you may run into cases where you still run into the file lock. By default VS enables retrys so usually the app will go offline during one of the retrys and all is good. In some cases it may take longer for ASP.NET to respond. That is a bit more tricky.

In the case that you add <EnableMSDeployAppOffline>true</EnableMSDeployAppOffline> and your app is not getting taken offline soon enough then I suggest that you take the app offline before the publish begins. There are several ways to do this remotely, but that depends on your setup. If you only have MSDeploy access you can try the following sequence:

1. Use msdeploy.exe to take your site offline by dropping app_offline.htm
2. Use msdeploy.exe to publish your app (_make sure the sync doesn't delete the app_offline.htm file_)
3. Wait some amount of time
4. Publish the site
5. Use msdeploy.exe to bring the app online by deleting app_offline.htm

I have blogged how you can do this at http://sedodream.com/2012/01/08/howtotakeyourwebappofflineduringpublishing.aspx. The only thing that is missing from that blog post is the delay to wait for the site to actually be taken offline. You can also create a script that just calls msdeploy.exe directly instead of integrating it into the project build/publish process.

There are known issues with IIS and file-locks (why they aren't solved yet i dont know).

The question i want to ask however is if you even need to re-deploy these files?

I recognize the file-names and recall them to be system-files which should either already be present on the server or simply not need to be re-deployed.

I am not very experienced when it comes to IIS but i have ran into this problem before and several of my more experienced co-workers have told me that this is as i said a known IIS-issue and i believe the answer to your question is:

1. Avoid deploying unnecessary files.
2. try again
3. Reset website
4. try again
5. iisreset