apt remove in Docker layers will no twork

[peponi]

Hi Sören

https://github.com/X9Developers/XSN/blob/7fe0dae12f747e4b157a72b5f1123cd61c2c95ba/Dockerfile#L39

this will not work, if you want to save image sizes because Docker images are composed in layers

every RUN command is one layer and will be safed (like in git)

you need to COPY first and merge the RUN commands in to one big command then you can apt remove the packages as last (all in the same Docker layer)

SECOND OPTION (better)

install and compile all in an build layer

https://docs.docker.com/develop/develop-images/multistage-build/#use-multi-stage-builds

notice COPY --from=0 /go/src/github.com/alexellis/href-counter/app .

you will copy the compiled files to a clean new image and the build layer will be erased

CLI TOOLS TO RESCUE

• https://github.com/wagoodman/dive - to inspect docker layer to shrink image size
• https://github.com/hadolint/hadolint - Dockerfile linter

[peponi]

ah

and try to take debian:stretch-slim this will safe also some MB

and http://download.oracle.com/berkeley-db/db-4.8.30.tar.gz should not be hard coded

move the url in a variable

ARG BERKLY_PKG_URL=http://download.oracle.com/berkeley-db/db-4.8.30.tar.gz

# Install Berkeley DB 4.8
RUN curl -L $BERKLY_PKG_URL | tar -xz -C /tmp && \

you can pass parameters to the docker build command via --build-arg

docker build -t xsn-test-build --build-arg BERKLY_PKG_URL=http://download.oracle.com/berkeley-db/db-4.8.30.tar.gz .

[peponi]

PR open

https://github.com/X9Developers/XSN/pull/149