VSTS CI/CD with docker and .NET Core 2.0 - Copy failed

Question

While following a couple .NET Core 2.0 Visual Studio Team Services Continuous Integration/Continuous Delivery examples I bumped into a copy error in VSTS.

Adding docker support via VS17 works great locally with a dockerfile like this.

FROM microsoft/aspnetcore:2.0
ARG source
WORKDIR /app
EXPOSE 80
COPY ${source:-obj/Docker/publish} .
ENTRYPOINT ["dotnet", "myapp.dll"]

With an MVC app and a WebAPI app it worked well with docker-compose locally.

When adding a VSTS CI build process and running it I kept hitting errors with the copy.

Building myapp Service 'myapp' failed to build: COPY failed: GetFileAttributesEx \?\C:\Windows\TEMP\docker-builder91\obj\Docker\publish: The system cannot find the path specified. C:\Program Files\Docker\docker-compose.exe failed with return code: 1

lko lko · Accepted Answer · 2017-12-04T00:53:26

The workaround that I've found is from this blog.

Note that they hit an error on a linux docker machine

COPY failed: stat /var/lib/docker/tmp/docker-builder613328056/obj/Docker/publish: no such file or directory /usr/bin/docker failed with return code: 1

Solution:

Make a Dockerfile.ci like this

FROM microsoft/aspnetcore-build:2.0 AS build-env
WORKDIR /app

# Copy csproj and restore as distinct layers
COPY *.csproj ./
RUN dotnet restore

# Copy everything else and build
COPY . ./
RUN dotnet publish -c Release -o out

# Build runtime image
FROM microsoft/aspnetcore:2.0
WORKDIR /app
COPY --from=build-env /app/out .
ENTRYPOINT ["dotnet", "SiliconValve.Vsts.DockerDemo.dll"]

It also requires modifying the .dockerignore file.

bin/
obj/
!*.dll
!obj/Docker/publish/*
!obj/Docker/empty/

This allows me to continue the CI process, however I assume there's an easier fix to the problem.

VSTS CI/CD with docker and .NET Core 2.0 - Copy failed

2 Answers