BUILDOUT_EXTENDS: Option missing

[arky]

I noticed that it is no longer possible to extend the plone-backend docker images using the BUILDOUT_EXTENDS option. The official plone image could be extended using the following dockerfile. ``` FROM plone:5.2 COPY extended_buildout.cfg /plone/instance/ RUN buildout -c extended_buildout.cfg ```

Here is an example of extended_buildout.cfg ``` [sources] politikus.contenttypes = git https://github.com/Sinar/politikus.contenttypes popolo.contenttypes = git https://github.com/Sinar/popolo.contenttypes ocds.contenttypes = git https://github.com/Sinar/ocds.contenttypes politikus.bods = git https://github.com/Sinar/politikus.bods politikus.theme = git https://github.com/Sinar/politikus.theme collective.vocabularies.iso = git https://github.com/Sinar/collective.vocabularies.iso politikus.extractives = git https://github.com/Sinar/politikus.extractives branch=main politikus.naturalresource = git https://github.com/Sinar/politikus.naturalresource branch=main plone.app.z3cform = git https://github.com/enfold/plone.app.z3cform/ branch=3.2.2+enfold1 [buildout] extends = buildout.cfg extensions = mr.developer always-checkout = force auto-checkout = * eggs += eea.facetednavigation politikus.contenttypes popolo.contenttypes politikus.bods ocds.contenttypes politikus.theme plone.app.imagecropping politikus.extractives politikus.naturalresource collective.vocabularies.iso Products.PloneHotfix20210518 collective.relationhelpers plone.app.z3cform plone.app.locales plone.volto languages = en km environment-vars = zope_i18n_compile_mo_files true [versions] Products.PloneHotfix20210518 = 1.4 eea.faceted.vocabularies = 7.0 eea.facetednavigation = 14.6 eea.jquery = 11.2 plone.app.imagecropping = 2.2.2 plone.app.jquery = 1.11.2 politikus.contenttypes==1.0a1 popolo.contenttypes==1.0a1 collective.dexteritytextindexer = 2.4.0 politikus.theme==1.0a1 collective.themefragments = 2.12 plone.app.themingplugins = 1.1 collective.relationhelpers = 1.5 plone.app.z3cform = 3.2.2+enfold1 parts += i18ndude precompile [i18ndude] unzip = true recipe = zc.recipe.egg eggs = i18ndude [precompile] recipe = plone.recipe.precompiler eggs = ${instance:eggs} plone.app.locales extra-paths = ${buildout:directory}/locales compile-mo-files = true ```

[ericof]

@arky The new images do not use buildout, but pip-based Plone installations, this is why we do not support BUILDOUT_EXTENDS

[avoinea]

@arky As @ericof said now you can just provide a constraints.txt and/or requirements.txt files:

FROM plone/plone-backend:6.0.0a1
COPY constraints.txt requirements.txt /app/
RUN ./bin/pip install -r requirements.txt -c constraints.txt ${PIP_PARAMS}

See Plone constraints.txt and requirements.txt as examples :wink: