Add poetry to dev stack

[thclark]

We need to install poetry, and pin the version.

The thing is it needs to be user specific. In slim builds the user is root:

ENV POETRY_HOME=/root/.poetry
RUN curl -sSL https://install.python-poetry.org | python -
ENV PATH "$POETRY_HOME/bin:$PATH"
RUN poetry config virtualenvs.create false

The thing is it needs to be user specific. In dev builds we need to install as the vscode user, not as root:

USER vscode
ENV POETRY_HOME=/home/vscode/.poetry
RUN curl -sSL https://install.python-poetry.org | python -
ENV PATH "$POETRY_HOME/bin:$PATH"
RUN poetry config virtualenvs.create false

EITHER

I'm not sure if a sensible thing might be to include additional stages to the build, so instead of:

• builder
• slim (which is actually both slim and dev)

We do:

• builder from ${BASE_IMAGE}
• common from ${BASE_IMAGE}
• slim from common
• dev from common

This will result in a small amount of duplicate code for the poetry installation, but will allow you to remove all the annoying if conditionals in for the dev tools.

OR

Experiment a bit and see if you can define the USER value based on a bash expression (root or vscode). Then do
ENV POETRY_HOME=$HOME/.poetry.

[thclark]

Deprecating in favour of #24