Add an environment variable for velocity secret

[Cubxity]

Is your feature request related to a problem?

When deploying Minecraft servers at scale, you would want to automate as much as you can. What I would like to achieve is an immutable Docker image to deploy my Minecraft server. I would like to store Bukkit, Spigot, Paper, etc config inside the Docker image. However, it is not a good idea to store sensitive information like forwarding secret inside a Docker image.

Describe the solution you'd like.

What would be ideal is to have an environment variable that can be defined at runtime, e.g. VELOCITY_FORWARDING_SECRET. This makes it easy to set in an environment like Kubernetes or Docker.

Describe alternatives you've considered.

I have considered templating paper.yml as a ConfigMap with a templating tool like Helm, but this creates an enormous ConfigMap.

Agreements

• I have searched for and ensured there isn't already an open issue regarding this.
• I have ensured the feature I'm requesting isn't already in the latest supported Paper build.

Other

No response

[MiniDigger]

ideally, we would have a full spring like value system, where every config entry can be overridden with a system property or an environment variable, rather than implementing ven vars manually

[Proximyst]

Perhaps moving to pico cli for all config options could help there, alternatively e.g. -paper-merge-config 'yaml file contents here' to merge into the YamlConfiguration before we start parsing?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[deniszitu]

Store sensitive information like forwarding secret inside a enviroment variable is a bad ideia, the correct thing is to use a file with the right permissions, like docker secret.

PaperMC/Velocity#463