For couple of years I’ve been using pip-tools for managing requirements but recently I faced with a problem of splitting requirements for dev and production environments. The problem was that if we just split requirements and compile them separately we will end up with different versions.

So next step is to use an approach from this article. The idea is to compile requirements.prod.in file first and than compile development part with requirements.prod.txt as constraints. It can be done like this:

-c requirements.prod.txt

# other requirements

This solution is also has drawbacks which I faced on the first try. I’v got unsolvable dependendencies between requirements.prod.txt and my development requirements. This conflict can be resolved manually, but it’s quite a tedious and not an elegant solution.

Next improvement is using intermediate file with all constraints, compile it and than build requirements. I found this solution in this comment to github issue. The author BTW is the same person, who wrote the article in the link above. Thank you, James Cooke.

Here my modified solution for Makefile:

## pip-compile: compile all requirements
pip-compile: prepare-constraints
	pip-compile constraints.in
	pip-compile requirements.prod.in
	pip-compile requirements.dev.in

## pip-upgrade: upgrade all requirements
pip-upgrade: prepare-constraints
	rm -f constraints.txt requirements.prod.txt requirements.dev.txt
	touch constraints.txt
	pip-compile constraints.in
	pip-compile requirements.prod.in
	pip-compile requirements.dev.in

prepare-constraints: check-pip-compile
	rm -f constraints.in
	touch constraints.txt
	cat requirements.*.in > constraints.in

## pip-sync:    sync requirements in local environment
pip-sync: check-pip-compile
	pip-sync requirements.prod.txt requirements.dev.txt

check-pip-compile:
	@which pip-compile > /dev/null

And you need to add a following string to each .in file:

-c constraints.txt

Also, here is an example of Dockerfile to build an image based on ARG:

ARG ENVIRONMENT="prod"
FROM python:3.9-buster AS app-prod
RUN pip3 install --upgrade pip
RUN useradd --no-create-home --gid root runner

WORKDIR /code

COPY requirements.prod.txt .
RUN pip3 install --no-cache-dir -r requirements.prod.txt

FROM app-prod AS app-dev
COPY requirements.dev.txt .
RUN pip3 install --no-cache-dir -r requirements.dev.txt

FROM app-${ENVIRONMENT} AS app

COPY . .

RUN chown -R runner:root /code && chmod -R g=u /code

USER runner

EXPOSE 8000

ENTRYPOINT [ "/code/docker-entrypoint.sh" ]

To create dev image, build it with argument ENVIRONMENT="dev"