More or less the default Dockerfile that comes from the VS 2019 template

Dockerfile

#See https://aka.ms/containerfastmode to understand how Visual Studio uses this Dockerfile to build your images for faster debugging.
# See Also: https://docker-curriculum.com/#sf-food-trucks
FROM mcr.microsoft.com/dotnet/core/aspnet:3.1-buster-slim AS base
WORKDIR /app
EXPOSE 80
EXPOSE 443

FROM mcr.microsoft.com/dotnet/core/sdk:3.1-buster AS build
WORKDIR /src
COPY ["AspNetCoreConfigExample.csproj", ""]
RUN dotnet restore "./AspNetCoreConfigExample.csproj"
COPY . .
WORKDIR "/src/."
RUN dotnet build "AspNetCoreConfigExample.csproj" -c Release -o /app/build

FROM build AS publish
RUN dotnet publish "AspNetCoreConfigExample.csproj" -c Release -o /app/publish

FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
ENV Secret:SuperDuperSecret="Artie is my friend in the Dockerfile"
ENTRYPOINT ["dotnet", "AspNetCoreConfigExample.dll"]