Make sure `github` user has sudo permissions: `github ALL=(ALL) NOPASSWD: /bin/bash /home/github/redeploy.sh*`.

deploy.yml

name: deploy
on:
  push:
    branches: main
jobs:
  push:
    runs-on: ubuntu-latest
    steps:
      - name: Check out repository
        uses: actions/checkout@v4

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Build Docker image
        uses: docker/build-push-action@v6
        env:
          DOCKER_BUILD_SUMMARY: false
        with:
          load: true
          tags: myapp:latest

      - name: Prepare SSH key
        run: |
          mkdir -p ~/.ssh
          echo "${{ secrets.SSH_KEY }}" | tr -d '\r' > ~/.ssh/id_rsa
          chmod 600 ~/.ssh/id_rsa

      - name: Add SSH host to known_hosts
        run: |
          ssh-keyscan -H "${{ secrets.SSH_HOST }}" >> ~/.ssh/known_hosts

      - name: Save image
        run: docker save myapp:latest | gzip | ssh ${{ secrets.SSH_USER }}@${{ secrets.SSH_HOST }} docker load

      - name: Run redeploy script
        run: ssh ${{ secrets.SSH_USER }}@${{ secrets.SSH_HOST }} sudo /bin/bash /home/github/redeploy.sh myapp

redeploy.sh

#!/bin/bash

# Ensure script receives an argument for container name
if [ -z "$1" ]; then
  echo "Usage: $0 <container_name>"
  exit 1
fi

CONTAINER_NAME=$1
APP_DIR="/var/lib/applications/$CONTAINER_NAME"
DATA_DIR="$APP_DIR/data"
PORT_FILE="$APP_DIR/port"
ENV_FILE="$APP_DIR/environment"

# Ensure the necessary files and directories exist
if [ ! -d "$APP_DIR" ]; then
  echo "Error: Directory $APP_DIR does not exist."
  exit 1
fi

if [ ! -f "$PORT_FILE" ]; then
  echo "Error: Port file $PORT_FILE does not exist."
  exit 1
fi

if [ ! -f "$ENV_FILE" ]; then
  echo "Error: Environment file $ENV_FILE does not exist."
  exit 1
fi

# Stop the existing container if it is running
echo "Stopping existing container: $CONTAINER_NAME"
docker stop "$CONTAINER_NAME" && docker rm "$CONTAINER_NAME"

# Read the port from the port file
PORT=$(cat "$PORT_FILE")
if [ -z "$PORT" ]; then
  echo "Error: Port is not specified in $PORT_FILE."
  exit 1
fi

# Read environment variables from the environment file
ENV_VARS=""
while IFS= read -r line; do
  ENV_VARS="$ENV_VARS -e $line"
done < "$ENV_FILE"

ENV_VARS="$ENV_VARS -e PORT=$PORT"

# Run the new container with the same name, exposing the port, and mounting the data volume
echo "Starting new container: $CONTAINER_NAME"
docker run --detach \
  --name "$CONTAINER_NAME" \
  --restart always \
  --publish "$PORT:$PORT" \
  --volume "$DATA_DIR:/data" \
  $ENV_VARS \
  "$CONTAINER_NAME:latest"

echo "Deployment complete: $CONTAINER_NAME is now running on port $PORT."

docker image prune --force