Commits on Nov 6, 2024

1. fix: wcow: add powershell.exe dir to default PATH …

   The current default `PATH` has been set to the most basic subset for both
   `nanoserver` and `servercore`.
   
   ```go
   const DefaultPathEnvWindows = "c:\\Windows\\System32;c:\\Windows;
   ```
   
   The path to `powershell.exe` is conspicuously missing hence breaking the
   developer experience for most workloads that depend on PS.
   
   This fix proposes to append `;C:\\Windows\\System32\\WindowsPowerShell\\v1.0`
   to that list to support PS scenarios, that make a big chunk of workloads,
   especially legacy ones, migrating from on-prem to cloud.
   
   Fixes moby#4901, microsoft/Windows-Containers#500
   Ref moby#3158
   
   Implication for nanoserver:
   ===========================
   This does not any way break the experiences for those using `nanoserver` base image,
   as much as PS and the `C:\\Windows\\System32\\WindowsPowerShell\\v1.0` path is not present
   on `nanoserver`.
   
   Transition users to using `ENV`:
   ==============================
   Users coming from classic `docker build` will need to transition from using `RUN setx /M`
   to `ENV` as a way of persisting environment variables in the images.
   
   We can take a hit on not supporting backward compatibility for `RUN setx /M`, as opposed
   to not supporting both `RUN setx /M` and `RUN powershell` as it is the case right now.
   
   Alternative considered:
   =======================
   We thought of an option to ask the Windows platform team
   to add a default `Config.Env.PATH` in the config file for the base image.
   However, this causes a regression for `RUN setx /M` on the classic `docker build`.
   There could be a couple of more people too that might be depending on `Config.Env = null`
   as it is currently. See `docker inspect mcr.microsoft.com/windows/servercore:ltsc2022`.
   
   Here is the regression details when we set `ENV` in the base image.
   
   ```
   PS> type .\Dockerfile
   FROM mcr.microsoft.com/windows/servercore:ltsc2022 AS newbase
   ENV PATH="C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Users\ContainerAdministrator\AppData\Local\Microsoft\WindowsApps"
   
   FROM newbase
   RUN setx /M PATH "C:\my\path;%PATH%"
   RUN echo %PATH%
   
   PS> docker build --no-cache -t profnandaa/servercore-path-tests .
   
   Sending build context to Docker daemon  2.048kB
   Step 1/5 : FROM mcr.microsoft.com/windows/servercore:ltsc2022 AS newbase
   ---> e64ba0f4256b
   Step 2/5 : ENV PATH="C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Users\ContainerAdministrator\AppData\Local\Microsoft\WindowsApps"
   ---> Running in ab3dc4921d7d
   ---> Removed intermediate container ab3dc4921d7d
   ---> f57b0a2d0e28
   Step 3/5 : FROM newbase
   ---> f57b0a2d0e28
   Step 4/5 : RUN setx /M PATH "%PATH%;C:\my\path;"
   ---> Running in 6ca6171334a0
   
   SUCCESS: Specified value was saved.
   ---> Removed intermediate container 6ca6171334a0
   ---> 6d2870e2f91d
   Step 5/5 : RUN echo %PATH%
   ---> Running in 785633e2a31c
   C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Users\ContainerAdministrator\AppData\Local\Microsoft\WindowsApps
      ^
      | ~~~~~~~~~ notice "C:\my\path" is missing, meaning `setx /M` is not persisting as before.
   
   ---> Removed intermediate container 785633e2a31c
   ---> ed490181b903
   Successfully built ed490181b903
   Successfully tagged profnandaa/servercore-path-tests:latest
   ```
   
   Current `RUN setx /M` behavior:
   
   ```
   PS> type .\Dockerfile
   
   FROM mcr.microsoft.com/windows/servercore:ltsc2022
   RUN setx /M PATH "%PATH%;C:\my\path;"
   RUN echo %PATH%
   
   PS> docker build --no-cache -t profnandaa/servercore-path-tests .
   
   Sending build context to Docker daemon  2.048kB
   Step 1/3 : FROM mcr.microsoft.com/windows/servercore:ltsc2022
   ---> e64ba0f4256b
   Step 2/3 : RUN setx /M PATH "C:\my\path;%PATH%"
   ---> Running in 5502dd679495
   
   SUCCESS: Specified value was saved.
   ---> Removed intermediate container 5502dd679495
   ---> 0b59f38e2da4
   Step 3/3 : RUN echo %PATH%
   ---> Running in 3bacb0b27bad
   C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Users\ContainerAdministrator\AppData\Local\Microsoft\WindowsApps;C:\my\path;
                       ^
                       |~~~~ `setx /M` persists.
   ---> Removed intermediate container 3bacb0b27bad
   ---> cda1b4cd27ff
   Successfully built cda1b4cd27ff
   Successfully tagged profnandaa/servercore-path-tests:latest
   ```
   
   `setx` vs. `ENV` has been discussed in details in moby#5445
   
   Signed-off-by: Anthony Nandaa <[email protected]>

   

   profnandaa committed Nov 6, 2024
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