Wrench

A small little program used to tell if Project Zomboid needs to restart due to a workshop update. It's designed to be used in any server setup.

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How do I use this?

Here's a small guide

Setup

Wrench requires some initial environment variables to work, you can read the most up to date ones by doing wrench -help.

Required:

• STEAM_WEB_KEY:xyz You need to create a steam web api key and pass it here, you can create one here. This is used to query steam's api for the latest workshop status
• ACF:path_to_file You must provide a path to the server's steam workshop acf file. The file sits in steam's workshop folder. The file for Project Zomboid should be called appworkshop_108600.acf. This is used to parse what mods are actively used on the server. You should never manually edit this file.

Optional:

• DISCORD_WEB_KEY You can provide a discord web hook here. The program will send a small message to said channel with a timestamp to next restart (currently 5 mins) and the list of mods that have updated (NOTE: Only past everything after https://discord.com/api/webhooks, this was to keep the env less bloated)
• USER_AGENT Is required if DISCORD_WEB_KEY is provided. This is attached to a request when scraping the changelog from steam. The format should include an email, and the programs name (example: Wrench - Changelog fetcher - your@email.com).

How does it work?

Key things to know:

• It parses the acf file to get a collection of mods
• It queries steam (in one call) with all the mods, and compares the timestamp from the acf to the latest version.
• Print's the mod(s) name that need to be updated in terminal (can be captured to be used elsewhere)
• It will return two different types of exit/term codes depending on the result.

Exit codes

• 0 Means the server should restart, there's an update
• 1 and higher means there's no update/error/crash/oh-god-run

Why use exit codes

I just wanted something that worked without having to over-engineer it

Might get changed in the future, but it's good enough for now, and can be paired with bash in useful ways (e.g. && or || based on if its successful or not)

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Example bash script with wrench integration

This is a simple bash script on how to use wrench, and how you could handle an update.

#!/bin/bash

export STEAM_WEB_KEY=abcdef
export ACF=/home/pz/workshop/appworkshop_108600.acf 
export DISCORD_WEB_KEY=1236712/abcade
export USER_AGENT="test@test.com"
 
while true; do 
    sleep 30
    # && means only run on successful exit (e.g. no error code 1 or higher)
    ./wrench && (sleep 5m; tmux kill-session -t pz; ./start_pz)
done;

How do I compile?

• Install rust (https://www.rust-lang.org/tools/install)
• Make sure you have nightly installed (for simd support when fetching changelogs)
• cargo build --release. The executable will be placed into a new folder called target/release