🚀 Customizing Leonardo with New Gems & Ruby on Rails Extensions

By default, Leonardo runs your Rails app (llamapress-simple) as a Docker image baked into the system. To add new Gems or deeper Rails customization, you’ll need to:

Clone & modify the Rails app
Build & push a new Docker image
Update Leonardo’s Docker Compose config to use your new image
Restart services inside your Leonardo instance

All changes will persist across EC2 stops/starts because the instance root volume lives on EBS.

1. Clone the Rails app locally

git clone https://github.com/KodyKendall/LlamaPress-Simple
cd LlamaPress-Simple

2. Add new gems

Add your gem with bundle add or edit the Gemfile directly:

bundle add devise
bundle install

This updates Gemfile and Gemfile.lock. Commit these changes if you want to keep them versioned.

3. Build a new Docker image

Use Docker Buildx to build for linux/amd64 (the platform EC2 runs):

docker buildx build \
  --platform linux/amd64 \
  -t your-dockerhub-username/llamapress-simple:0.1.18 .

Push the image to Docker Hub:

docker push your-dockerhub-username/llamapress-simple:0.1.18

4. SSH into your Leonardo instance

From your local machine:

ssh ubuntu@your-instance-ip

Navigate to the Docker Compose directory:

cd ~/llamapress

5. Update `docker-compose.yml`

Open the file:

nano docker-compose.yml

Find the service for llamapress and update the image tag:

llamapress:
  image: your-dockerhub-username/llamapress-simple:0.1.18
  build: .
  ports:
    - "3000:3000"
  # other options…

Save and exit.

6. Pull & restart the container

docker compose pull llamapress
docker compose up -d llamapress

This pulls your new image and restarts the container in detached mode.

7. Verify

Check logs:

docker compose logs llamapress

Visit your Leonardo instance in the browser → your Rails app is now running with the new gems.

⚡ Notes

Changes to docker-compose.yml persist across stops/starts. (Your instance’s filesystem is preserved).
To make new users get the updated config by default, bake a new AMI with the updated compose file.
Use semantic versioning for your images (e.g., 0.1.18, 0.1.19) to avoid confusion.