🌱 update dockerfiles to just copy the code

[kannon92]

Fixes #4524

As I have worked on a few kubebuilder based projects, I always find over time that I switch to using a similar behavior for the template.

It causes quite a bit of confusion as it is usually not a common practice when you add folders that you must remember to add them to the Dockerfile also.

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[Kavinjsir]

Hey @kannon92 splitting out dependency installation steps in your Dockerfile can help Docker build cache more efficiently and usually speeds up the build process. You might also want to check out the official Docker CLI for generating a Go-specific Dockerfile—it shows exactly why copying go.mod and go.sum in separate steps is a best practice.

# Download dependencies as a separate step to take advantage of Docker's caching.
# Leverage a cache mount to /go/pkg/mod/ to speed up subsequent builds.
# Leverage bind mounts to go.sum and go.mod to avoid having to copy them into
# the container.
RUN --mount=type=cache,target=/go/pkg/mod/ \
    --mount=type=bind,source=go.mod,target=go.mod \
    go mod download -x

# This is the architecture you're building for, which is passed in by the builder.
# Placing it here allows the previous steps to be cached across architectures.
ARG TARGETARCH

# Build the application.
# Leverage a cache mount to /go/pkg/mod/ to speed up subsequent builds.
# Leverage a bind mount to the current directory to avoid having to copy the
# source code into the container.
RUN --mount=type=cache,target=/go/pkg/mod/ \
    --mount=type=bind,target=. \
    CGO_ENABLED=0 GOARCH=$TARGETARCH go build -o /bin/server ./api

[camilamacedo86]

Thank you for your contribution. 🎉

The proposed change replaces the current approach, where we only add specific paths (cmd/, api/, internal/, etc.), with COPY . ., which adds everything from the root of the project. Am I correct?

This means that unnecessary files and directories like hack/, test/, README, and other root-level files will now be included in the manager image, even if they are not required.

While this might seem convenient, however, it shows like goes against best practices by unnecessarily bloating the image. That is why we promote to explicitly copy only the paths we need to ensure a clean and optimized image, avoiding the inclusion of unrelated files. See: https://docs.docker.com/build/building/best-practices/#dont-install-unnecessary-packages

Does that make sense?

/hold

[camilamacedo86]

Could we agree to close this one?

[camilamacedo86]

Hi @kannon92

Thank you a lot for your contribution 🥇 and for looking to make kubebuilder

But as@Kavinjsir pointed out: #4525 (comment)
Also, see my comment: #4525 (comment)

What you suggested does not seem to align with Docker's best practices: https://docs.docker.com/build/building/best-practices/#dont-install-unnecessary-packages

Therefore, I do not think that we should not move forward here.
Does that make sense ?

So, I hope that you do not mind, but I am closing this one and the PR as deferred