terraform libvirt pci passthrough provisioning + simple python utility

libvirt_pci.tf

variable "instance_name" {}
variable "image_path" {}
variable "libvirt_uri" {}
variable "pci_devices" {
  type    = list(string)
  default = []
}

provider "libvirt" {
  uri = var.libvirt_uri
}

resource "libvirt_domain" "domain" {
  name   = var.instance_name
  memory = "1024"
  disk {
    volume_id = libvirt_volume.volume.id
  }

  dynamic "host_device" {
    for_each = var.pci_devices
    content {
      source = host_device.value
    }
  }
}

resource "libvirt_volume" "volume" {
  name   = "${var.instance_name}_volume"
  pool   = "default"
  source = var.image_path
  format = "qcow2"
}

tf_wrapper.py

import click
import os
import subprocess
import logging

@click.group()
def cli():
    pass

@click.command()
@click.option('--instance-name', prompt=True, help='The name of the instance.')
@click.option('--image-path', default='/var/lib/libvirt/images/', help='The path to the image directory.')
@click.option('--disk-size', prompt=True, help='The size of the disk in GB. If 0, no disk will be created.')
@click.option('--tf-path', prompt=True, help='The path to the Terraform script.')
@click.option('--libvirt-uri', envvar='LIBVIRT_URI', default='qemu:///system', help='The libvirt URI.')
@click.option('--pci-devices', help='Comma-separated list of PCI devices to pass through to the guest.')
def provision(instance_name, image_path, disk_size, tf_path, libvirt_uri, pci_devices):
    """Provision a VM instance using Terraform and libvirt."""

    # Set environment variables for Terraform
    os.environ['TF_VAR_instance_name'] = instance_name
    os.environ['TF_VAR_image_path'] = image_path + instance_name + '.qcow2'
    os.environ['TF_VAR_libvirt_uri'] = libvirt_uri
    os.environ['TF_VAR_pci_devices'] = pci_devices.split(',') if pci_devices else []

    # Create disk image if disk size is not 0
    if disk_size != '0':
        try:
            subprocess.run(['qemu-img', 'create', '-f', 'qcow2', os.environ['TF_VAR_image_path'], disk_size + 'G'], check=True)
        except subprocess.CalledProcessError as e:
            logging.error(f'qemu-img command failed with exit code {e.returncode}')
            return

    # Call Terraform script
    try:
        subprocess.run(['terraform', 'init', tf_path], check=True)
        subprocess.run(['terraform', 'apply', '-auto-approve', tf_path], check=True)
    except subprocess.CalledProcessError as e:
        logging.error(f'Terraform command failed with exit code {e.returncode}')
        return

cli.add_command(provision)

if __name__ == '__main__':
    cli()