srt-game-server

Overview

srt-game-server originated as a proof of concept backend multiplayer game server with the end goal of supporting clients in web browsers via a messaging broker.

It is written in C++ and depends on the following libraries:

• Box2D v2.3.0 - 2D physics engine
• POCO C++ Libraries v1.9.0 - cross-platform C++ libraries for building network and internet-based applications
• Protocol Buffers v3.y - language-neutral, platform-neutral extensible mechanism for serializing structured data
• Qpid Proton v0.31 - AMQP v1.0 / ISO 19464:2014 messaging protocol

And has traditionally been using Apache ActiveMQ as the message broker. Original development took place in Xcode, with an unsophisticated CMake based build more recently added.

Building from scratch on Fedora 33

If you're on linux (fedora) you're going to need to install some dependencies and packages before you can build locally

Install dependant packages

sudo cp ./containerbuild/srt.repo /etc/yum.repos.d/
sudo dnf install gcc gcc-c++ cmake yaml-cpp yaml-cpp-devel Box2D-2.3.1-12.fc32.x86_64 Box2D-devel-2.3.1-12.fc32.x86_64 compat-openssl10 openssl poco-devel poco-foundation protobuf protobuf-devel gcc g++ cmake git qpid-proton-cpp qpid-proton-cpp-devel --assumeyes --verbose

Rebuild the .proto bindings

cd ./src/Proto
for i in $(ls -lC1 *.proto); do protoc $i --cpp_out=.; done;

Build with cmake

From the project root run:

mkdir build && cd build
cmake ../
cmake --build .

Start the server

After you've run the build steps above it will output a srt-game-server executable in your project root. Run this with the following arguments:

./srt-game-server --broker-uri "tcp://${BROKER_IP}:5672" -v 8 --sleep-cycle 2000

Where $BROKER_IP is the IP address of the running Artemis broker see Start Artemis Broker

Configuration options

You can configure the server either with command line arguments or in a config.yaml file. Command line args take precedence.

Command line args	config.yaml	Defaults
--broker-uri	broker-uri	"tcp://127.0.0.1:5672"
--sleep-cycle	sleep-cycle	50
--command-in	command-in	"COMMAND.IN"
--game-event-out	game-event-out	"GAME.EVENT.OUT"
--force-multiplier	force-multiplier	5000.0

Visual Studio Remote Container Support

If you have Visual Studio Code with the Remote Container extension, you are able to build, run, and debug the game server without having to install anything additional on your laptop.

The container has docker installed and mounts the hosts /var/run/docker.sock so you can run containers on the host machine

Starting up VS Code

1. Clone the git repo
2. Open Visual Studio Code in the root of repo
3. When prompted to open the folder in a container, accept the prompt

Building the code

1. Simply run the "Build" task
   • This will use cmake to create the necessary build information and then build the server

Debugging (and Running) the code

1. Open a terminal and run the Artemis broker in a container

docker run --name artemis -it --rm -p 5672:5672 \
-e AMQ_USER=admin -e AMQ_PASSWORD=admin -e AMQ_ALLOW_ANONYMOUS=true \
quay.io/artemiscloud/activemq-artemis-broker:latest

2. Go to the Debug tab
3. Click the play button for "Launch Main"
   • When prompted enter the hostname or IP address of the artemis broker and also the port number (e.g. 5672 - the default insecure AMQP port)
4. The game server should start up and connect to the broker

Containerization

In the containerbuild directory is a Fedora 33-based Dockerfile for running the srt-game-server via your favorite container runtime. Build and run testing was performed using podman on a Fedora 33 host.

You can build the container using the following command, ensuring first that you are in the root folder of this repo:

podman build -v `pwd`:/tmp/srt-game-server:Z -t localhost/redhat-gamedev/srt-game-server:latest .

Quick and Dirty Local Testing

You can run an Artemis broker locally in a container, and then connect the game server to it. Currently, the broker must be run with a root-ful container (via sudo).

Start the Artemis broker

In one terminal:

sudo podman run --name artemis -it --rm -p 5672:5672 \
-e AMQ_USER=admin -e AMQ_PASSWORD=admin -e AMQ_ALLOW_ANONYMOUS=true \
quay.io/artemiscloud/activemq-artemis-broker:latest

Start the server

In another terminal:

export BROKER_IP=`sudo podman inspect artemis | grep IPAddress | cut -d: -f2 | cut -d\" -f2`
podman run --name srt-game-server \
-e BROKER_URI="tcp://$BROKER_IP:5672" \
-it --rm quay.io/redhat-gamedev/srt-game-server:latest