Hercules in Docker

A Docker setup for building and containerising the Ragnarok Online server emulator Hercules.

What is this?

This repository specifically contains everything you need to build a Hercules server with minimal effort, provided you have a working Docker installation. If you're happy to run pre-built Docker containers made using this setup, check out the "How do I run a Ragnarok Online server with this?" section further down.

If you want to know what Docker is, here is a good overview.

How does this work?

The Dockerfile is a three-stage definition for Docker:

• Step 1 (build_hercules) will bring up a Linux (Debian Bullseye, specifically) container, install all the necessary requirements for compiling Hercules, build Hercules and copy all the files required for Hercules alone into a separate distribution directory inside the container.

• Step 2 (export_build) will copy the distribution created in the build_hercules step to an empty container. This can be used to easily copy the build out of the build containers to your host machine by using the --output parameter for docker build:

  docker build --target export_build \
    --output type=tar,dest=hercules.tar
  

  will build Hercules and save the finished build in the hercules.tar archive in your current directory.

• Step 3 (build_image) will take the build produced by the build_hercules step and copy it into another Debian Bullseye container, all prepared so you can simply run the Hercules server with a single docker run command.

If you just want to run a server without making your own build, there are standard images built and published from this repository via automated builds whenever a new version of Hercules is released.

These images are always built with the current release version of Hercules, for Intel/AMD (most home computers), ARMv6 (Raspberry Pi 1), ARMv7 (Raspberry Pi 2 and equivalents) and ARM64 (Raspberry Pi 3 or 4 and equivalents) systems and available in both Classic and Renewal mode.

How do I run a Ragnarok Online server with this?

I'm making images available for both Renewal and Classic servers using both the latest packet version supported by Hercules and packet version 20180418, which matches the "Noob Pack" client download available on the Hercules forums for ease of use.

In order to run any of these images, you will of course first need to install Docker on the computer you want to run the server on.

Then, download the docker-compose.yaml file from this repository and copy it somewhere. You can just use it as is to just bring up a server, but do feel free to have a closer look at its contents. There are a number of variables you can edit to e.g. lock down database access more tightly.

To bring up your Ragnarok game server and the database it needs, open a command prompt or terminal window, navigate to where you saved the docker-compose.yaml file and simply run docker-compose up -d. Docker will download the images for the game and database servers and start them.

If you want to watch things happen, just run docker-compose up to run the services in the foreground. To exit out of this view, simply press Ctrl-C; NOTE that this will shut down the services though!

You can check the status of your services with docker ps; this should list both the database and game_servers containers as "running" once they have started. They will continue running in the background even if you close the command-line window and you should be able to create accounts and connect to the server.

How do I build Hercules with this?

I'd rather build my own Docker image

Simply run docker build . -t hercules. This will run the build and package it up in a local image tagged hercules, which you can run either with docker run hercules or using the docker-compose.yml file (above) to bring up an entire setup with its own database service and everything.

I don't want to run Hercules from a Docker image. Can I just get the build?

You can run only the first stage of the Dockerfile to build Hercules without packaging it up in an image. To just build Hercules and copy the build to your local machine, run:

docker build . -t hercules --target export_build \
  --output type=local,dest=out.tar

Note that this will be a Linux build, so if you want to run this on a Windows host you might need to put some more work in. I'd be happy to accept pull requests to make this all work with and produce Windows builds, too!

I'd rather build a Renewal server. And what about packet version [whatever]?

To build a Renewal rather than a Classic server or a specific packet version, modify your docker build command with the HERCULES_SERVER_MODE and/or HERCULES_PACKET_VERSION build arguments:

docker build . -t hercules [--target build_hercules] \
  --build-arg HERCULES_SERVER_MODE=[classic|renewal] \
  --build-arg HERCULES_PACKET_VERSION=[whatever]

I'm a developer. Can I use this with my own copy of the Hercules source code?

Sure you can! Simply remove the existing hercules directory in this repository and copy your copy of the source code there instead. Any builds created from then on will be built from this copy instead.

If you already have a git repository with the Hercules source for your modifications or plugins, you could also simply replace the submodule:

git submodule deinit hercules
rm -rf hercules
git submodule add https://github.com/me/my-hercules-repo ./hercules

Read up on git submodules for more information on how that all works.