nickwesselman / dotnet-docker-lock-issue

Windows Docker Hyper-V File Lock Issue

Reproducing

1. docker-compose build
2. docker-compose up -d
3. Open http://localhost:8090/ and confirm the ASP.NET Core app is running.
4. Monitor app build via docker-compose logs -f dotnet-docker-lock-issue
5. Make a change to a file in the app (e.g. add/remove whitespace from Startup.cs)

Expected

dotnet watch kills the running app, rebuilds, and runs the app again

Actual

dotnet watch is able to kill the app, but the build fails with one of two errors:

CSC : error CS2012: Cannot open 'C:\src\obj\container\Debug\net5.0\dotnet-docker-lock-issue.dll' for writing -- 'The process cannot access the file 'C:\src\obj\container\Debug\net5.0\dotnet-docker-lock-issue.dll' because it is being used by another process.' [C:\src\dotnet-docker-lock-issue.csproj]

C:\Program Files\dotnet\sdk\5.0.202\Microsoft.Common.CurrentVersion.targets(4919,5): warning MSB3026: Could not copy "C:\src\obj\container\Debug\net5.0\apphost.exe" to "C:\src/bin/container/Debug\net5.0\dotnet-docker-lock-issue.exe". Beginning retry 1 in 1000ms. The process cannot access the file 'C:\src\bin\container\Debug\net5.0\dotnet-docker-lock-issue.exe' because it is being used by another process. [C:\src\dotnet-docker-lock-issue.csproj]

Observed file locks

Following the failed build, neither the bin\ nor obj\ folders appear to have any open handles on the container itself. However the container host seems to be holding them in the Hyper-V VM process.

On the container

PS C:\> handle64 -accepteula C:\src\obj\

Nthandle v4.22 - Handle viewer
Copyright (C) 1997-2019 Mark Russinovich
Sysinternals - www.sysinternals.com

No matching handles found.

PS C:\> handle64 -accepteula C:\src\bin\

Nthandle v4.22 - Handle viewer
Copyright (C) 1997-2019 Mark Russinovich
Sysinternals - www.sysinternals.com

No matching handles found.

On the host

PS C:\> handle64.exe C:\dev\dotnet-docker-lock-issue\obj\

Nthandle v4.22 - Handle viewer
Copyright (C) 1997-2019 Mark Russinovich
Sysinternals - www.sysinternals.com

vmwp.exe           pid: 17640  type: File          35DC: C:\dev\dotnet-docker-lock-issue\obj\container\Debug\net5.0\d377a3cb-bad4-4c2d-8e66-e6a46db6ba2c_dotnet-docker-lock-issue.dll

PS C:\> handle64.exe C:\dev\dotnet-docker-lock-issue\bin

Nthandle v4.22 - Handle viewer
Copyright (C) 1997-2019 Mark Russinovich
Sysinternals - www.sysinternals.com

vmwp.exe           pid: 17640  type: File          3520: C:\dev\dotnet-docker-lock-issue\bin\container\Debug\net5.0\dotnet-docker-lock-issue.exe
vmwp.exe           pid: 17640  type: File          3524: C:\dev\dotnet-docker-lock-issue\bin\container\Debug\net5.0\dotnet-docker-lock-issue.dll
vmwp.exe           pid: 17640  type: File          3568: C:\dev\dotnet-docker-lock-issue\bin\container\Debug\net5.0\dotnet-docker-lock-issue.Views.dll