Multistage poetry build

[kaliif]

Gets rid of exporting requirements.txt on dependency update by adding a stage for poetry in Dockerfile. Installed packages are copied to the final stage without poetry. What do you think?

[alanbchristie]

Wow - the Dockerfile's got a lot more complex. Not sure you need 3 FROM statements, and maybe the POETRY_VERISON could be an ARG rather than an ENV? Also - wouldn't it be a lot easier to simply export to a requirements.txt file in the first image so the second image simply did a pip install as it used to? Creating a .env and copying that between images using PYTHONPATH just seems too complicated. At least we can;t forget to export but the result is a complicated Dockerfile. I like the idea but I think it could be a lot simpler - i.e. do the export in image 1 then copy the requirements to the next image?

[kaliif]

Poetry seems to be deprecating requirements.txt export, got this warning when building earlier:

Warning: poetry-plugin-export will not be installed by default in a future version of Poetry.
In order to avoid a breaking change and make your automation forward-compatible, please install poetry-plugin-export explicitly. See https://python-poetry.org/docs/plugins/#using-plugins for details on how to install a plugin.
To disable this warning run 'poetry config warnings.export false'.

Not sure which way will be simpler in the future.