DockBridge

DockBridge

Velocity plugin to auto-register Docker-backed servers (e.g., Limbo) and check for updates on Modrinth.

Features

- Auto-discovery: Containers with label `net.uebliche.dockbridge.autoregister=true` are registered as Velocity servers. Host from container name, port from label `net.uebliche.dockbridge.server_port` (fallback: first exposed port, else 25565). - Name collisions: Default `suffix` → append short container id (`basename-abcdef`). Alternative `overwrite` → keep basename, last writer wins. - `/dockbridge` command (permission `dockbridge.command`): Shows label filter, duplicate strategy, last scan stats, and registered servers (no sensitive data). - Modrinth update check on proxy start; login hint for players with permission `dockbridge.update.notify`.

Installation

1) Download the latest DockBridge release from Modrinth (jar file). 2) Place the jar into your Velocity `plugins/` folder. 3) (Optional) If Velocity runs in Docker, mount `/var/run/docker.sock` into the Velocity container so DockBridge can discover containers. 4) Start Velocity. On first start, the config file `dockbridge.conf` is created in the Velocity data folder; adjust settings and restart. 5) Permissions: - `dockbridge.command` for `/dockbridge` - `dockbridge.update.notify` for update hints on login

Configuration

`dockbridge.conf` (created in the Velocity data folder on first start): ``` docker.endpoint=unix:///var/run/docker.sock docker.poll_interval_seconds=30 filters.proxy_group=default docker.autoregister.label_key=net.uebliche.dockbridge.autoregister docker.autoregister.label_value=true docker.autoregister.name_label=net.uebliche.dockbridge.server_name docker.autoregister.port_label=net.uebliche.dockbridge.server_port docker.autoregister.duplicate_strategy=suffix # suffix | overwrite ```

Docker labels (example)

``` net.uebliche.dockbridge.autoregister=true net.uebliche.dockbridge.server_name=limbo net.uebliche.dockbridge.server_port=30000 ```

Local testing

Gradle run

``` ./gradlew runVelocity ``` Downloads Velocity, builds the plugin (shadowJar), and starts the proxy with the plugin loaded.

Docker Compose (Limbo set)

``` docker compose up --build # or: docker compose -f docker-compose.limbo.yml up --build ``` Includes three Limbo backends (ports 30000/30001/30002) and Velocity on host port 26678. Velocity runs via `runVelocity` inside the container and mounts your sources/config.

Commands & permissions

- `/dockbridge` (permission `dockbridge.command`): Status and registered servers. - Update hint on login: permission `dockbridge.update.notify`.

Troubleshooting

- No servers registered? - Ensure your containers have the label `net.uebliche.dockbridge.autoregister=true` and a valid `net.uebliche.dockbridge.server_port`. - Make sure Velocity can reach Docker: mount `/var/run/docker.sock` (or set `docker.endpoint` to a reachable TCP endpoint). - Check `/dockbridge` output for last scan count and registered servers. - Port mismatch or forwarding errors? - Verify the Limbo (or other backend) port matches the label and the server properties. - For Velocity forwarding, ensure forwarding secret/mode match on both ends. - Duplicate names? - Default strategy is `suffix`. Switch to `overwrite` via `docker.autoregister.duplicate_strategy` if you want last-writer-wins.

Build

``` ./gradlew build ``` Produces the shaded jar at `build/libs/DockBridge-<version>.jar`.

Contributing

- Fork & PRs welcome. Keep code comments minimal but purposeful. - Default Java 21, Gradle Kotlin DSL, Velocity API 3.4.0-SNAPSHOT for run task; 3.1.1 for compileOnly/annotationProcessor. - Run `./gradlew build` before submitting; Docker-based tests are optional.