Automatically set directory ownership when using NEXTCLOUD_DATA_DIR

I'm using the nextcloud docker image (nc version 20.0.6.1). It seems to have support for setting NEXTCLOUD_DATA_DIR, but there are issues.

Snippet of my docker-compose file:

  app:
    image: nextcloud:fpm-alpine
    restart: unless-stopped
    volumes:
      - nextcloud:/var/www/html
      - nc_data:/opt/nextcloud/data
    environment:
      - MYSQL_HOST=db
      - REDIS_HOST=redis
      - OVERWRITEWEBROOT=/nextcloud
      - NEXTCLOUD_DATA_DIR=/opt/nextcloud/data
    env_file:
      - db.env
    depends_on:
      - db
      - redis

Issue 1: Permissions on NEXTCLOUD_DATA_DIR are not set

If you try this, nextcloud installation (with browser button 'Install') does not work, because 'www-data:root' has no permission to write to /opt/nextcloud/data.

Workaround

Before starting the installation process in the browser, log into the container and fix the permissions, i.e.

$ podman exec -it <nextcloud-container-id> sh
/var/www/html # chown -R www-data:root /opt/nextcloud/data/

It would be great if the /entrypoint.sh script would set the permissions appropriate.

Issue 2: appdata directory at NEXTCLOUD_DATA_DIR location must be served

If I use the workaround above to complete the installation process, I could log in, but there are missing resources. This is because after the install, my NEXTCLOUD_DATA_DIR (/opt/nextcloud/data) looks like this:

# ls -l /opt/nextcloud/data/
total 12
drwxr-xr-x    4 www-data www-data        32 Feb  7 08:18 admin
drwxr-xr-x    8 www-data www-data        89 Feb  7 08:18 appdata_ocvkg7lyrl56
-rw-r--r--    1 www-data www-data         0 Feb  7 08:17 index.html
-rw-r-----    1 www-data www-data      9736 Feb  7 08:18 nextcloud.log

# ls -l /opt/nextcloud/data/appdata_ocvkg7lyrl56/
total 0
drwxr-xr-x    2 www-data www-data        23 Feb  7 08:17 appstore
drwxr-xr-x    3 www-data www-data        19 Feb  7 08:18 avatar
drwxr-xr-x   11 www-data www-data       147 Feb  7 08:43 css
drwxr-xr-x    3 www-data www-data        19 Feb  7 08:18 dashboard
drwxr-xr-x    4 www-data www-data        34 Feb  7 08:18 js
drwxr-xr-x    8 www-data www-data        60 Feb  7 08:18 preview

# ls -l /opt/nextcloud/data/appdata_ocvkg7lyrl56/css/
total 0
drwxr-xr-x    2 www-data www-data        97 Feb  7 08:18 activity
drwxr-xr-x    2 www-data www-data       215 Feb  7 08:18 core
drwxr-xr-x    2 www-data www-data       109 Feb  7 08:18 dashboard
drwxr-xr-x    2 www-data www-data        55 Feb  7 08:18 icons
drwxr-xr-x    2 www-data www-data       100 Feb  7 08:18 notifications
drwxr-xr-x    2 www-data www-data       106 Feb  7 08:43 settings
drwxr-xr-x    2 www-data www-data        97 Feb  7 08:18 text
drwxr-xr-x    2 www-data www-data       103 Feb  7 08:18 theming
drwxr-xr-x    2 www-data www-data       130 Feb  7 08:18 user_status

# ls -l /opt/nextcloud/data/appdata_ocvkg7lyrl56/js
total 0
drwxr-xr-x    2 www-data www-data        97 Feb  7 08:18 activity
drwxr-xr-x    2 www-data www-data       118 Feb  7 08:18 core

There are a bunch of files inside /opt/nextcloud/data/appdata_ocvkg7lyrl56 that needs to be served by the web server (i.e. nginx in my case). However, the whole idea of using NEXTCLOUD_DATA_DIR is to harden the installation (with better protecting user data).

Perhaps it is possible to move stuff under /opt/nextcloud/data/appdata_<random_id> to the nextcloud directory (/var/www/html for nextcloud-docker) in the /entrypoint.sh script?

Start by reading /entrypoint.sh and trace how NEXTCLOUD_DATA_DIR is handled during container startup and installation. Reproduce the docker-compose setup with the mounted data volume, then verify ownership and whether appdata resources remain usable when the data directory is outside /var/www/html. Done means both reported installation and missing-resource cases are addressed without requiring the manual chown workaround.