Building a Docker image from a multi project dot net core solution

Question

I am trying to build a docker image from a visual studio solution that consists of two projects:

• one project contains common code (http methods, logging etc)

Answer 1

If you use "standard" Dockerfile template from Visual Studio, you might have issue with having your "common" project being built on your local PC (probably windows) and the "main" project being built in docker container (probably Linux). the "main" dll is referencing windows-built dll, hence the issues.

Make sure you are copying not only main project, but also the common project, so dotnet can build it in docker also.

Try out this dockerfile:

FROM microsoft/aspnetcore:2.0 AS base
WORKDIR /app
ENV ASPNETCORE_ENVIRONMENT=Production
ENV ASPNETCORE_URLS http://*:5000
EXPOSE 5000

FROM microsoft/aspnetcore-build:2.0 AS builder
ARG Configuration=Release
WORKDIR /src
COPY *.sln ./
COPY Project.Main/Project.Main.csproj Project.Main/
COPY Project.Common/Project.Common.csproj Project.Common/
RUN dotnet restore
COPY . .
WORKDIR /src/ProjectMain
RUN dotnet build -c $Configuration -o /app

FROM builder AS publish
ARG Configuration=Release
RUN dotnet publish -c $Configuration -o /app

FROM base AS final
WORKDIR /app
COPY --from=publish /app .
ENTRYPOINT ["dotnet", "Project.Main.dll"]

Although is to build the "Main" project, it's executed on the sln level.