script to check for optical drive changes and update docker-compose files

update-mkv.sh

#!/bin/sh

# Path to the Docker Compose file
DOCKER_COMPOSE_FILE="/volume2/mkv/makemkv-docker/docker-compose.yml"

find_device_paths_from_compose() {
    echo "Searching for device paths in the Docker Compose file..."
    device_path_sr=$(grep -o '/dev/sr[^:"]*' "$DOCKER_COMPOSE_FILE" | head -n1)
    device_path_sg=$(grep -o '/dev/sg[^:"]*' "$DOCKER_COMPOSE_FILE" | head -n1)

    # Ensure empty results are handled
    device_path_sr=${device_path_sr:-""}
    device_path_sg=${device_path_sg:-""}
}

restart_container() {
    echo "Restarting container..."
    docker-compose -f "$DOCKER_COMPOSE_FILE" down
    docker-compose -f "$DOCKER_COMPOSE_FILE" up -d
}

find_device_paths_from_compose
echo "docker device paths:      sr=$device_path_sr sg=$device_path_sg"

# Determine the actual paths of /dev/sr* and /dev/sg*
new_path_sr=""
new_path_sg=""

for device in /dev/sr*; do
    if [ "$device" != "/dev/sr*" ]; then
        new_path_sr="$device"
        chmod 666 $device
        break
    fi
done

for device in /dev/sg*; do
    if [ "$device" != "/dev/sg*" ]; then
        new_path_sg="$device"
        chmod 666 $device
        break
    fi
done

echo "host devices path:        sr=$new_path_sr sg=$new_path_sg"

# Check if the paths have changed
if ([ -n "$new_path_sr" ] && [ "$new_path_sr" != "$device_path_sr" ]) || \
   ([ -n "$new_path_sg" ] && [ "$new_path_sg" != "$device_path_sg" ]); then
    echo "New drive paths found. Updating Docker Compose file..."

    # Run `sed` only if the variables are not empty
    if [ -n "$new_path_sr" ] && [ -n "$device_path_sr" ]; then
        sed -i "s|/dev/sr[0-9]:/dev/sr[0-9]|$new_path_sr:$new_path_sr|"  "$DOCKER_COMPOSE_FILE"
    fi
    if [ -n "$new_path_sg" ] && [ -n "$device_path_sg" ]; then
        sed -i "s|/dev/sg[0-9]:/dev/sg[0-9]|$new_path_sg:$new_path_sg|"  "$DOCKER_COMPOSE_FILE"
    fi

    restart_container
else
    echo "drive paths are matching those defined in the docker compose file"
    docker-compose -f "$DOCKER_COMPOSE_FILE" up -d
fi