R36S – Persisting game saves with GitHub repositories

R36S – Persisting game saves with GitHub repositories

I purchased an R36S portable emulator recently and, after erasing everything and installing a clean distro from scratch, my first action was to persist the game saves.

Why? Because over the years, losing save games has been one of the most frustrating experiences for me. I explored a few ways to implement cloud storage solutions—like Dropbox, Google Drive, and OneDrive—but after a while, Git repositories seemed like the best option.

A Git repository allows these small files to be stored along with their different versions over time. I don’t expect the repository to grow too large, and I don’t plan to abuse it, so I’m going to use GitHub as my remote. If it grows, I can change the remote later or adjust my strategy.

Configuring the RetroArch save folders

TThe first thing I did was change the save file directory from the individual ROM folders to the global /home/ark/.config/retroarch/saves/ instead.

OOpen RetroArch and go to Settings > Directory > Save Files.

Do the same for the Save States

Don’t forget to persist your configuration file before quitting.

Then, I created two private repositories: k36-saves and k36-states.

Creating the SSH keys

After enabling Wi-Fi or LAN on your R36S, log in via SSH using your preferred method (SSH, WSL SSH, PuTTY, etc.).
In my case, I used the following command:

ssh -o PreferredAuthentications=password ark@192.168.0.12

When asked for a password, I used the default ark
Now, you can create the SSH keys:

ssh-keygen -t rsa

This creates a public/private key pair in your user’s home folder.
Copy the contents of /home/ark/.ssh/id_rsa.pub and add them to your GitHub Settings > SSH and GPG keys section.
If you have other repositories, I recommend creating a separate account since this provides full write access to your repositories.

Creating the Local Repositories

Now, let’s go to the previously mentioned saves folder and initialize the repository there:

cd /home/ark/.config/retroarch/saves/
git init
git remote add origin git@github.com:viniciusrezende/k36-saves.git
git checkout -b main

Replace the remote URL with your own repository.
Repeat the same process for the states folder.

While we’re here, let’s configure the global information for the Git user:

git config --global user.email "ark@viniciusrezende.com.br"
git config --global user.name "ArkOS k36"

Creating the Auto-Commit / Auto-Push Script

Now, let’s create the script in our home folder:

touch ~/pushgit.sh
chmod +x ~/pushgit.sh
nano ~/pushgit.sh

Then paste the following contents:

set -e
timestamp=$(date +"%Y-%m-%d %H:%M:%S")

cd /home/ark/.config/retroarch/saves
if ! git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
  exit 1
fi
if [[ -n "$(git status --porcelain)" ]]; then
  echo "Changes detected. Committing..."
  git add -A
  git commit -m "Auto commit: $timestamp"
fi
git push origin main

cd /home/ark/.config/retroarch/states
if ! git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
  exit 1
fi
if [[ -n "$(git status --porcelain)" ]]; then
  echo "Changes detected. Committing..."
  git add -A
  git commit -m "Auto commit: $timestamp"
fi
git push origin main

Adding the cron event

For the last step, open the crontab with crontab -e and add the following line:

*/5 * * * * bash /home/ark/pushgit.sh

Extra

While writing this, I had some issues taking screenshots from the R36S.
For anyone curious, I used the following command:


sudo ffmpeg -f kmsgrab -i - -frames:v 1 -vf "hwdownload,format=bgr0" screenshot.png

Git repository access control with Gitolite

Git repository access control with Gitolite

I already used other version control software like CVS and SVN in the past, but Git was one that really got me because I just felt it easy and intuitive.

Besides having a GitHub account I really don’t see the point of paying US$7/month just to have private repositories when you can roll your own VPS for less than that. Obviously, you can install something more similar to GitHub like GitLab, but, in my opinion, Gitolite is easy to use, fast and works; Keep it simple, sucker!

So, I will give the steps to install and configure on Ubuntu Server 16.04. On other distros the paths and steps may differ.

First of all, you should check existing SSH keys or generate a new set on your machine. (To be honest, if you are already using git you should have your keys)

#to check:
ls -al ~/.ssh
#to generate(linux/mac):
ssh-keygen -t rsa

On Windows machines I advise you to install cygwin with net/openssh package. I prefer that way, but you can try with other methods.

Back to our server, now we should install gitolite3 and git-core:

sudo apt-get install git-core gitolite3

Insert your public key configure gitolite. On older versions you need to create a user and run the setup by yourself, keep that in mind if you are using other distro.

Now you can ssh the gitolite user to list the repositories:

ssh gitolite3@yourdomain.com

You can add some rules and keys cloning the gitolite-admin repository.

git clone gitolite3@youtdomain.com:gitolite-admin

You can now add pub keys for other users(or machines) creating files in the keydir directory. For multiple machines you should use the name convention user@machine.pub, like nimlhug@notebook.pub. On the conf/gitolite.conf file you can add users and repositories.

Checkout the official documentation. Apart from being a non resource-intensive, gitolite is a rich and powerful software that you can make use of RegEx, groups, hooks, VREF, wild repos and much more.