Cookiecutter-zope-instance and enviroment variables - split sensitive data in an extra file

Plone Support Deployment & hosting
2

I solved this by generating it in my custom entry point in a step like so:

./bin/python dockerinstance.py
make VENV=off VENV_FOLDER=. INSTANCE_YAML=dockerinstance.yaml instance

with dockerinstance.py a hacky script:

import os
import yaml


# prefix all environment variables like so:
# (after prefix a valid cookiecutter-zope-instance key is needed)
PREFIX = "INSTANCE_"

# load base instance.yaml
with open("instance.yaml", "r") as fio:
    instance = yaml.safe_load(fio)
cfg = instance["default_context"]

# set values from enviroment
for envkey, value in os.environ.items():
    if not envkey.startswith(PREFIX):
        continue
    key = envkey[len(PREFIX) :].lower()
    print(f"Set from env {envkey}: {key}={value}")
    cfg[key] = value


# write file
with open("dockerinstance.yaml", "w") as fio:
    yaml.dump(instance, fio)

Then I can use environment variables in my docker swarm yaml file like so:

services:
  plone:
    environment:
      INSTANCE_client_home: /data
      INSTANCE_wsgi_listen: 0.0.0.0:8080
      INSTANCE_wsgi_fast_listen: ""
      INSTANCE_wsgi_threads: 2
      INSTANCE_debug_mode: "false"
      INSTANCE_initial_user_name: ${INITIAL_USER_NAME?unset}
      INSTANCE_initial_user_password: ${INITIAL_USER_PASSWORD?unset}
      INSTANCE_db_storage: relstorage
      INSTANCE_db_blobs_mode: cache
      INSTANCE_db_cache_size: ${ZODB_CACHE_SIZE_OBJECTS?unset}
      INSTANCE_db_cache_size_bytes: ${ZODB_CACHE_SIZE_BYTES?unset}
      INSTANCE_db_relstorage: postgresql
      INSTANCE_db_relstorage_postgresql_dsn: host='db' dbname='plone' user='plone' password='${DB_PASSWORD?unset}'
      INSTANCE_db_relstorage_cache_local_mb: ${RELSTORAGE_LOCAL_MB?unset}

This is not thought all to the end, but as a rough plan something like this in an enhanced way should go into the mainline for cookiecutter-plone-starter at some point.