[Improvement idea] Create startup option for installation of ffmpeg / other packages.

[Moltey]

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Challenge:

• I need to install ffmpeg for video previews in my nextcloud container (running fpm-alpine).
• The container is running in a rootless environment (I strongly believe rootless environments will be the future of containerization due to IT Security).
• Contrary to comments of @J0WI in #1432 , it is not easy to post-install package in a rootless environment due to insufficient access privileges:

~ $ id
uid=1008(1008) gid=10080(10080)
~ $ apk update
ERROR: Unable to lock database: Permission denied
ERROR: Failed to open apk database: Permission denied

Request:

• I kindly request to add a startup-option (environment variable) to select additional packages to be installed during the spinup of the container.
• Example:

$ docker run -d \
    -e ADD_PACKAGE="ffmpeg" \
    docker.io/library/nextcloud:fpm-alpine

[PrivatePuffin]

"Rootless" means all code(!) is executed as non-root. There is simply no privilage-escalation allowed after the container is started.

So, no this cannot be done. As root also cannot magically run commands if you asked it to with an env-var either.

Remember: Anything you cannot do in a container shell, also cannot be done from the entrypoint either.

[especially-relative]

The right way to do this is a dockerfile that looks roughly like this:

FROM nextcloud:<version>
USER root
RUN apt update; apt install <packages>; apt <cleanup>
USER www-data

The user switching probably isn't needed since the nextcloud image defaults to running as root.

[FunctionDJ]

Until there's an official solution i'm using docker-compose to install ffmpeg into the container during creation, see https://github.com/nextcloud/docker/issues/1432#issuecomment-1326436158

[J0WI]

Duplicate of #820