Update Docker integration guide to prefer COPY over ADD for simple cases

[MatthijsKok]

Summary

Docker best practices recommend to use COPY when the additional functionality of ADD is not used.

See:

• https://docs.docker.com/build/building/best-practices/#add-or-copy
• https://www.docker.com/blog/docker-best-practices-understanding-the-differences-between-add-and-copy-instructions-in-dockerfiles/

Test Plan

Docs only change

[zanieb]

I'm fine with using COPY but I'd rather not change the ordering of the working directory as well. I find it less clear to COPY . .

[zanieb]

Can you revert this change too please?

[MatthijsKok]

The first example was the only one that did not start with the WORKDIR, so I thought I'd align them.
But whatever you prefer :) I can see how this is simpler in a way.

Reverted.

[zanieb]

Ah I didn't notice that, I presume we need it earlier in the other ones because we're relying on it for the cache mounts. I'm not quite sure how I feel about it.

[MatthijsKok]

The cache mounts all target the absolute path /root/.cache/uv, so they are not impacted by WORKDIR.

[MatthijsKok]

Personally I always start my dockerfiles with a WORKDIR, so I moved it without too much thought haha.

It's not that important :) The current situation is perfectly fine

[zanieb]

hm?

uv/docs/guides/integration/docker.md

Lines 408 to 412 in e7af583

	# Install dependencies
	RUN --mount=type=cache,target=/root/.cache/uv \
	--mount=type=bind,source=uv.lock,target=uv.lock \
	--mount=type=bind,source=pyproject.toml,target=pyproject.toml \
	uv sync --locked --no-install-project

[zanieb]

Sorry, "bind mounts" :)

[MatthijsKok]

ahhh. ok that makes a lot more sense!

I think the dilemma can be summed up as

• "WORKDIR statement before first time it's used" vs
• "WORKDIR statement at the start of the file" (potentially 'far away')

whatever you think is best <3

[MatthijsKok]

thought: with only 1 statement making use of the WORKDIR you could even

RUN uv --directory=app sync --locked