mc-go

Compiled Go replacement for the legacy mc fish function. Manages local Minecraft servers on laptoo.

yep this is entirely vibecoded.

Built for one homelab. This is written for and tested only on laptoo (Alpine Linux, OpenRC, my own directory layout). It can be adapted to other systems — see Portability — but it is not portable as-is, and it has no CI, no test suite and no security audit. Read the source before running it anywhere that matters.

Requirements

The binary is static, but most commands shell out to system tools:

Needed for	Dependency
everything	tmux (server process manager), pgrep, tar, ss, pkill
java / setup pickers	fzf — optional; falls back to a numbered prompt
setup … flags	$EDITOR — optional; falls back to a single-line prompt
bot	node + a bot engine (mineflayer, plus bedrock-protocol for -b) — not shipped in this repo
notifications	notify-send + paplay, and an ntfy token file — all optional

The bot engine lives outside this repo (default ~/mc/bot/index.js / index-bedrock.js + node_modules, see bot_dir); mc bot only launches it.

Usage

mc <command> [server]

  start        Start server in tmux
  stop         Stop server gracefully
  restart      Restart server gracefully
  console      Attach to server console
  logs         View logs (tail -f)
  backup       Create backup
  restore      Restore from backup
  status       Check if server is running
  check        Check server files
  rmworld      Delete world folder
  list         List all servers
  watch        Check mc-watcher status
  whitelist    Manage whitelist (list|add <player>|remove <player>)
  bot          Manage offline bots (list|join [username] [-b]|kick <username>)
  java         Configure per-server Java version (fzf picker)
  setup        Unified setup: Java + RAM + JVM flags (fzf menu)
  config       Show or edit runtime paths (~/.config/mc/config.json)

java

mc java                # check all + pick server→JVM via fzf
mc java check          # table: .java_version health + suggestions
mc java list           # installed JVMs (<jvm_root>/*/bin/java)
mc java <srv>          # pick JVM for <srv> via fzf
mc java <srv> 21       # set non-interactively (8|17|21|25 or label/path)

setup

mc setup               # pick server → interactive menu (fzf)
mc setup <srv>         # menu: Java / RAM / Flags / View / Reset
mc setup <srv> java [jvm]
mc setup <srv> ram [Xmx] [Xms]   # e.g. `mc setup survival ram 6G` or `8G 4G`
mc setup <srv> flags "[flags]"   # raw JVM flags
mc setup check         # table: Xms/Xmx + flags + java health

Build

go build -o mc .
sudo install -m 755 mc /usr/local/bin/mc

Layout

• main.go — CLI dispatch + server discovery helpers
• commands.go — per-subcommand implementations
• exec.go — tmux orchestration + stop-timeout/retry + tty keyboard prompt
• notify.go — desktop notify-send (host GUI env), paplay sound, ntfy push
• bot.go — offline bot state/kick integration (<bot_dir>/.bots/*)
• config.go — runtime config (~/.config/mc/config.json), Aikar flags, per-server .java_args
• java.go — JVM discovery (<jvm_root>/*/bin/java) + mc java checker & fzf picker
• setup.go — mc setup unified menu (Java + RAM + flags, fzf + $EDITOR fallback)

Configuration

Paths and a few layout assumptions are read from ~/.config/mc/config.json. The file is optional: if it is missing, every value falls back to the original laptoo layout, so an existing install keeps working with no config at all.

Key	Default	Meaning
server_root	~/mc	one directory per server (each must contain a .jar)
backup_dir	/mnt/HDD/mc	where backup writes and restore looks for archives
jvm_root	/usr/lib/jvm	scanned as <jvm_root>/*/bin/java
bot_dir	~/mc/bot	bot engine (index.js), .bots state and logs
sounds_dir	~/mc/library/sounds	.ogg files used by desktop notifications
tmp_dir	/var/tmp	-Djava.io.tmpdir in the built-in default JVM flags
session_prefix	mc-	tmux session name = <prefix><server>
ntfy_url	http://127.0.0.1:8989	local ntfy base URL
ntfy_token_file	/etc/sysmon/tokens/ntfy.sh	file containing NTFY_TOKEN=...

Any subset of keys may be set; empty or missing keys use the default. Values may use ~ and $VARS, and paths under $HOME are written back as ~/.... Manage it without editing JSON by hand:

mc config                 # show effective values + whether each came from the file
mc config path            # print the config file path
mc config init [--force]  # write a full default config
mc config set <key> <val> # change one key (rewrites the whole file)
mc config help            # keys + defaults

Changing tmp_dir only affects the built-in default flags. A server with its own .java_args keeps whatever -Djava.io.tmpdir= it already has.

Portability

The defaults reproduce this homelab, but the remaining OS assumptions are still real:

• services.sh in sysmon (a separate repo) is OpenRC-only, and sysmon reads Alpine's /var/log/messages — that is unrelated to mc.
• mc expects tmux, pgrep, tar, ss and pkill on PATH.
• Per-server Java is a path in .java_version; java on PATH is the fallback when no file exists.
• mc-watcher (separate repo) hardcodes ~/mc/<server> and tmux sessions named mc-<server>. If you change server_root or session_prefix, the watcher will not see those servers/sessions unless you patch it too.
• Desktop/ntfy notifications degrade quietly when notify-send, paplay or the token file are missing.

Everything in the table above is configurable without a rebuild.

Behavior notes

• Stop sends stop to the console, waits 30s, then offers a force-kill. Pressing any key jumps straight to the prompt; y force-kills. If declined it retries the 30s wait up to 3 times, then lists any surviving tmux session / java PID for manual handling.
• Jar name and java provider come from server.properties/.java_version using the Aikar flags (was $mcargs in the fish version).
• Per-server Java: ~/mc/<srv>/.java_version stores the java binary path (e.g. /usr/lib/jvm/java-21-openjdk/bin/java). mc java discovers installed JVMs via <jvm_root>/*/bin/java and shows version + suggestion based on jar name (1.7→8, 1.17→17, 26.x→25). Picker is fzf with rounded border (falls back to numbered prompt when no TTY/fzf).
• Per-server RAM/flags: ~/mc/<srv>/.java_args (also .mc_args/.jvm_args) stores raw JVM flags. Missing → built-in Aikar flags (-Xms2G -Xmx4G …). mc setup edits both .java_version and .java_args in one fzf menu: Java picker, RAM picker (fzf presets 512M→16G + custom), Flags editor ($EDITOR on temp file or single-line prompt). View shows the final java <flags> -jar <jar> --nogui command.