# ADR 0001: RCON-only Minecraft server interaction (no console, no file editing)

## Status

Accepted

## Context

The webUI needs to interact with the running Minecraft server for several operations: querying player count (dashboard), managing the whitelist, managing OPs, and managing bans. Two primary approaches exist:

1. **File editing** — Read and write `whitelist.json`, `ops.json`, `banned-players.json` directly on disk. Requires a server restart or `/reload` to apply changes.
2. **RCON** — Send commands over the RCON protocol. Changes apply immediately, no restart needed. Also enables querying server state (`/list`).
3. **Docker stdin/stdout** — Attach to the container's console. Enables log streaming and command input. Requires persistent WebSocket/SSE connection.

## Decision

We will use **RCON exclusively** for all webUI-to-server interaction:

- Player count queries via RCON `/list`
- Whitelist, OP, and ban management via RCON commands (`/whitelist add`, `/op`, `/ban`, etc.)
- No log streaming, no Docker console attachment
- No direct editing of `whitelist.json`, `ops.json`, or other server files
- RCON password is auto-generated per Instance and stored internally

## Consequences

### Positive
- Changes apply immediately without server restart
- No WebSocket or SSE infrastructure required
- No log parsing or streaming complexity
- User-facing player management is username-based (users don't need to know UUIDs or JSON structure)
- Simpler codebase: request/response pattern over TCP, not persistent connections

### Negative
- No server logs visible in the webUI — debugging crashes requires Docker CLI access (but this is a system administration concern, out of scope for the webUI)
- RCON must be enabled and reachable (`enable-rcon=true`, port exposed) for the webUI to function for live Instance operations
- If the Minecraft process crashes inside the container, RCON becomes unreachable and the webUI can only report "crashed — check Docker logs" rather than showing the error