GCP App Engine, Docker for windows, asp.net core and Cloudstore NoSQL

I have an app engine instance running on GCP and a sample app which I can run directly from Visual studio (Windows) and I can update the cloudstore db. I can also deploy the app to GCP.

I need an authentication key to access the service account in GCP from docker, so I've added it to the project in SweepstakesLinux/Keys so the so it gets copied to docker by the dockerfile.

However when I try to run it in Docker, I get this error

: 'Error reading credential file from location /app/SweepstakesLinux/Keys/KEY_NAME.json: Could not find file '/app/SweepstakesLinux/Keys/KEY_NAME.json'.

My Dockerfile looks like this

FROM gcr.io/google-appengine/aspnetcore:2.1
COPY . /app
WORKDIR /app

# Environment Variables
ENV GOOGLE_APPLICATION_CREDENTIALS /app/SweepstakesLinux/Keys/KEY_NAME.json


ENTRYPOINT ["dotnet", "SweepstakesLinux.dll"]

I can connect to the docker image using

docker run -it --entrypoint sh sweepstakeslinux:dev

and I can see the file exists in the directory.



If I run $GOOGLE_APPLICATION_CREDENTIALS from the docker container, it seems to find the file, but not the fields in it


and if I run grep vi $GOOGLE_APPLICATION_CREDENTIALS it can open the file but some of the key value pairs seem to be missing:


I've also tried mounting a local folder from my PC to access and copy the key from there by running

docker run -v C:\Users\Phil\Keys:/keys --entrypoint sh sweepstakeslinux:dev

but it just results in this error:

No executable found matching command "dotnet-SweepstakesLinux.dll"

Any ideas?