allow for pre/post/error script hooks after any option

[ffariajr]

Description

Allows custom scripts to be run before or after an LGSM command runs. Also in case of error.
I use this to open ports in my firewall.

Fixes #2764

Type of change

• Bug fix (a change which fixes an issue).
• New feature (a change which adds functionality).
• New Server (new server added).
• Refactor (restructures existing code).
• Comment update (typo, spelling, explanation, examples, etc).

Checklist

PR will not be merged until all steps are complete.

• This pull request links to an issue.
• This pull request uses the develop branch as its base.
• This pull request subject follows the Conventional Commits standard.
• This code follows the style guidelines of this project.
• I have performed a self-review of my code.
• I have checked that this code is commented where required.
• I have provided a detailed enough description of this PR.
• I have checked if documentation needs updating.

Documentation

If documentation does need updating either update it by creating a PR (preferred) or request a documentation update.

• User docs: https://github.com/GameServerManagers/LinuxGSM-Docs
• Dev docs: https://github.com/GameServerManagers/LinuxGSM-Dev-Docs

Thank you for your Pull Request!

[ffariajr]

Wrong linked issue, the correct issue is #2764

[ffariajr]

accompanying documentation PR GameServerManagers/LinuxGSM-Docs#96

[dgibbs64]

What an interesting idea. I would love to know a few more cases that people might do with it. Opening ports is a really good idea.

[ffariajr]

The user in #2764, although it was 3 years ago, said that there was a bug in SteamCMD with installing mods that are > 1GiB in size, and he wanted to download it using the script instead on Post-Update or Pre-Start.

Off the top of my head, I used to run a small Minecraft server and I wrote a wrapper script to shut off the anti-virus while the server was running to save on resources.

Or Post-Backup it uploads the backup to a service and deletes the local backup.

[ncraig419]

could a single hook be added at the very beginning of linuxgsm.sh?
I have a dockerized instance of linuxgsm that take a minute for the network to init before calls for DNS can be made. I would love a way to have a hooked sh wait for the network to respond before allowing any calls to github or steam to fire.
A Normal system boot would prevent this with systemd network needed in the service unit files

LinuxGSM/linuxgsm.sh

Lines 341 to 344 in 8dfed10

	# LinuxGSM installer mode.
	if [ "${shortname}" == "core" ]; then
	# Download the latest serverlist. This is the complete list of all supported servers.
	fn_bootstrap_fetch_file_github "lgsm/data" "serverlist.csv" "${datadir}" "nochmodx" "norun" "forcedl" "nomd5"