Docker RUN dotnet Build always cached resulting in consecutive fault-CodePudding

I am currently struggling with Docker builds for .net Core 3.1 where RUN steps are cached, which they should not as this should always be executed:

#10 [build 4/4] RUN dotnet publish "WKIS Solution.sln" -c UserManagementFrontendRelease -p:version=1.2.4 -o /app/publish --configfile FrontendWebApplication.UserManagement.Cicd/nuget.config
#10 sha256:e8aeefc43305f5ab93d8c8fb78658174bdaa14d42c560daf9d764848da7f251c
#10 CACHED

Which is most likely the cause for the following step to fail: ERROR: "/app/publish" not found: not found:

#14 [final 2/2] COPY --from=base /app/publish .
#14 sha256:4a30ee4113a62bfd40731cdb0cd3a498eaee357df5736019ebd0629bd07f178e
#14 ERROR: "/app/publish" not found: not found

I updated the Docker Desktop on Windows to version 20.10.11, build dea9396, the output of the result looks slightly different, but the same result:

=> CACHED [base 2/2] WORKDIR /app                                                                                 0.0s
=> CACHED [build 2/4] WORKDIR /src                                                                                0.0s
=> CACHED [build 3/4] COPY . .                                                                                    0.0s
=> CACHED [build 4/4] RUN dotnet publish "WKIS Solution.sln" -c UserManagementFrontendRelease -p:version=1.2.4 -  0.0s

The docker file is quite simple:

FROM registry.intranet.company/ubi8/dotnet-31-runtime AS base

WORKDIR /app
EXPOSE 80

FROM registry.intranet.company/ubi8/dotnet-31 AS build

WORKDIR /src
USER root
COPY . .

RUN dotnet publish "WKIS Solution.sln" -c UserManagementFrontendRelease -p:version=1.2.4 -o /app/publish --configfile FrontendWebApplication.UserManagement.Cicd/nuget.config

USER default
FROM build AS final

WORKDIR /app
COPY --from=base /app/publish .
ENTRYPOINT ["dotnet", "FrontendWebApplication.UserManagement.dll"]

I've already tried the following to solve the issue:

Prune all in docker
Stop and start Docker Desktop
Calling docker build --no-cache
Adding the --no-cache option in the RUN statement inside the Dockerfile, like so: RUN dotnet publish "WKIS Solution.sln" -c UserManagementFrontendRelease -p:version=1.2.4 -o /app/publish --configfile FrontendWebApplication.UserManagement.Cicd/nuget.config --no-cache

I am not 100% sure if the cache is responsible for the folder which can't be found, so the reason might be something complete different, but as I couldn't find a way to to disable the cache, I simply don't know and it's the best guess I have.

CodePudding user response：

The last copy command should be from build, not from base, you are publishing into the build payer but then creating final from the base layer. Caching isn't the issue.

COPY --from=build /app/publish .