In reviewing the generic "builder" abstraction that allows arbitrary command execution we realized this could be used to implement already existing builders (e.g., python/pip and nodejs/npm).
Rather than implement new builders for all potential package managers/languages we should abstract this by making builder generic enough to satisfy all these cases.
Just playing around:
providers:
- name: python
fields:
- name: python
type: mapping
fields:
- name: version
type: string
- name: requirements
type: "[]string"
phases:
preinstall:
- env:
PIP_WHEEL_DIR: "{{.PythonLibPrefix}}"
PIP_FIND_LINKS: "file://{{.PythonLibPrefix}}"
- copy: { sources: ["{{join .Requirements ','}}"] }
...