Luanti git backups

Linux Only: This mod is specifically designed for Linux/Unix environments. It utilizes nice and ionice for process prioritization. Windows is not supported.

Introduction

A high-performance, automated snapshot system using git version control for Luanti worlds. This mod leverages git to provide lightweight, incremental backups of your world state with minimal impact on server performance.

Features

• Automated Snapshots: Periodically saves the world state (default: every 15 minutes).
• Low Impact: Uses nice and ionice to ensure backup processes don't cause lag spikes for players.
• git Hash Identification: Every snapshot is identified by its unique git hash, making rollbacks precise and tamper-proof.
• Easy Rollbacks: Revert the entire world to any previous snapshot via chat command or the in-game GUI.
• In-Game GUI: A graphical interface for browsing, committing, and reverting snapshots without typing commands.
• In-Game Log: View snapshot history with hashes, timestamps, and relative ages without leaving the game.
• Safety First: Automatic git lock cleanup, countdown broadcast, player kick, and graceful shutdown during reverts.

Requirements

1. git: Must be installed on the host system.
2. Operating System: Linux/Unix only (required for nice and ionice).
3. Permissions: Requires an insecure environment to execute system commands.

Installation

1. Clone the repository into your mods folder:

git clone https://github.com/Senal-D-A-Gunaratna/luanti_git_backups.git ~/.minetest/mods/luanti_git_backups

2. Enable the mod in your world configuration.

3. Required: Add this mod under Trusted mods using the Luanti Settings GUi

• enable Show advanced settings
• go to Developer Options → Trusted Mods
• add luanti_git_backups under Trusted Mods

Updating

cd ~/.minetest/mods/luanti_git_backups
git fetch --all
git reset --hard origin/main

Configuration

Use the Luanti Settings GUi

• go to the mods section Luanti git backups Value is in seconds. Default is 900 seconds (15 minutes)

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Usage

All commands require server privileges.

Chat Commands

Command	Alias	Description
/git commit	-c	Manually create a world snapshot.
/git log	-l	Show the last 15 snapshots with hash, timestamp, and age.
/git revert <hash>	-r <hash>	Revert the world to the specified snapshot hash and restart the server.
/git gui	-g	Open the in-game snapshot GUI.

In-Game GUI

Open with /git -g or /git gui. Requires server privileges.

The GUI provides:

• Scrollable snapshot list showing hash, timestamp, and age for up to 50 recent snapshots.
• Commit Snapshot button to manually trigger a backup.
• Revert to Selected button — select a row then click to revert. A confirmation dialog will appear showing the hash and timestamp before anything is changed.
• Refresh button to reload the snapshot list.

How Reverting Works

Whether triggered by command or GUI:

1. All players receive a warning broadcast with a 5-second countdown.
2. All connected players are kicked with a notification.
3. The world is hard-reset to the selected git commit.
4. The server shuts down automatically so the database reloads cleanly on next start.

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Technical Notes

• Snapshot Identity: Snapshots are identified by their git short hash (e.g. a3f9c1d). Both the chat command and GUI accept short hashes. This is more reliable than sequential numbers, which can shift after a revert.
• Storage Efficiency: git stores only deltas between snapshots, making it far more disk-efficient than .zip or .tar backups.
• Auto Initialisation: On first run the mod automatically runs git init in your world folder if no repository exists.
• Lock Cleanup: Stale .git/index.lock files are automatically removed before each commit to prevent backup failures.

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Credits & Licensing

• Code: Licensed under the MIT License.
• Git Logo: Original logo by Jason Long, licensed under CC BY-SA 3.0.