feat: cron job for pruning docker images

[VinneyJ]

Description

This change introduces a scheduled cron job on the Dev server to automatically prune unused Docker images every 4 hours. The main objective is to manage disk space efficiently by removing old and unused Docker images, thus preventing potential space-related issues that can cause PRs to fail. This maintenance task ensures that the development environment remains clean and that only relevant Docker images are retained.

Fixes # (issue)

• Fixes disk space issues caused by the accumulation of old Docker images on the DEV instance(s).
• Resolves PR failures due to insufficient disk space.

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation

[kilemensi]

👍🏽

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1. Name should include prune I think e.g. docker-prune-cron, etc.
2. Should we prune everything?

[kilemensi]

Normally you don't want scripts laying around in a home folder. You usually put them in say ~/.local/bin, etc.

But since we're going to develop this further to be part of Dokku plugin ecosystem, I guess we can leave it here for now.

[thepsalmist]

🚀 mostly LGTM. I agree with @kilemensi , since docker system prune gives you a --volumes option, no need to have them as two separate commands

-f, --force Do not prompt for confirmation
--volumes Prune anonymous volumes

I've learnt its never a good idea to have sudo within scripts; you can have a check if script is being run as a user with sudo privileges.

[VinneyJ]

I've learnt its never a good idea to have sudo within scripts; you can have a check if script is being run as a user with sudo privileges.

I have realized that running the script directly with sudo, like sudo ./docker_prune_cron.sh, doesn't seem to work. Our options are to either modify the sudoers file or add user to the docker group. I'm not sure if everyone is comfortable with any of these approaches in the dev server. @thepsalmist

[thepsalmist]

I've learnt its never a good idea to have sudo within scripts; you can have a check if script is being run as a user with sudo privileges.

I have realized that running the script directly with sudo, like sudo ./docker_prune_cron.sh, doesn't seem to work. Our options are to either modify the sudoers file or add user to the docker group. I'm not sure if everyone is comfortable with any of these approaches in the dev server. @thepsalmist

@VinneyJ why would this not work, any error logs?

[VinneyJ]

No stdout log at all, @thepsalmist. Nothing appears even in the logs file.