How to create & run .net Core Console App in docker

Question

I have a .NET Core 2.1 console app. I want to run this console app in a Docker image. I'm new to Docker and just trying to figure it out.

At this time, I have a Dockerfile, which was inspired from Microsoft's Example. My file actually looks like this:

FROM microsoft/dotnet:2.1-runtime-nanoserver-1709 AS base
WORKDIR /app

FROM microsoft/dotnet:2.1-sdk-nanoserver-1709 AS build
WORKDIR /src
COPY MyConsoleApp/MyConsoleApp.csproj MyConsoleApp/
RUN dotnet restore MyConsoleApp/MyConsoleApp.csproj
COPY . .
WORKDIR /src/MyConsoleApp
RUN dotnet build MyConsoleApp.csproj -c Release -o /app

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

FROM base AS final
WORKDIR /app
COPY --from=publish /app .
ENTRYPOINT ["dotnet", "MyConsoleApp.exe"]

My question is, what is the difference between: microsoft/dotnet:2.1-runtime-nanoserver-1709, microsoft/dotnet:2.1-sdk, and microsoft/dotnet:2.1-runtime? Which one should I use for my .NET 2.1 console app? I'm confused as to if I a) build my console app then deploy it to a docker image or b) build a docker image, get the code, and build the console app on the image itself. Any help is appreciated.

Answer 1

It's a question more not about docker itself, but .net docker images

You can go to the https://hub.docker.com/r/microsoft/dotnet/ click in particular image find Dockerfile and understand what exactly software builds in this image and find the difference between different Dockerfile's

Regarding second question better to "build a docker image, get the code, and build the console app on the image itself." So you build the image, expose port, mount your code as volume, and your code executes inside the container with help of software installed in the container

Answer 2

For anyone interested in actual Dockerfile reference:

FROM microsoft/dotnet:2.2-sdk AS build
WORKDIR /app

COPY <your app>.csproj .
RUN dotnet restore <your app>.csproj

COPY . .
RUN dotnet publish -c Release -o out

FROM microsoft/dotnet:2.2-aspnetcore-runtime AS runtime
WORKDIR /app
COPY --from=build /app/out ./

ENTRYPOINT ["dotnet", "<your app>.dll"]