libvirt-executor

#!/usr/bin/env bash
set -o nounset -o errexit -o pipefail
readonly libvirt_default_pool_path="/var/lib/libvirt/images"

ssh() {
  command ssh \
    -i "/etc/libvirt-executor/id_ed25519" \
    -F /dev/null \
    -o ServerAliveCountMax=2 \
    -o ServerAliveInterval=15 \
    -o UserKnownHostsFile=/dev/null \
    -o StrictHostKeyChecking=off \
    "root@${1}" "${@:2}"
}

vm_name() {
  printf 'runner-%s-project-%d-pipeline-%d-job-%d\n' "${CUSTOM_ENV_CI_RUNNER_SHORT_TOKEN}" "${CUSTOM_ENV_CI_PROJECT_ID}" "${CUSTOM_ENV_CI_PIPELINE_IID}" "${CUSTOM_ENV_CI_JOB_ID}"
}

vm_ip() {
  local ip
  ip="$(virsh -q domifaddr "${1}" | awk -F'[ /]+' '{print $5}')"
  if [[ -n ${ip} ]]; then
    echo "${ip}"
    return 0
  fi
  return 1
}

wait_for_ssh() {
  for _ in {1..30}; do
    if ! ip="$(vm_ip "${1}")"; then
      echo "Waiting for network"
      sleep 1
      continue
    fi
    if ! ssh "${ip}" true; then
      echo "Waiting for SSH to be ready"
      sleep 1
      continue
    fi
    printf "%s" "${ip}"
    return 0
  done
  echo 'Waited 30 seconds for VM to start, exiting...'
  exit "${SYSTEM_FAILURE_EXIT_CODE:-1}"
}

# https://docs.gitlab.com/runner/executors/custom.html#prepare
prepare() {
  # shellcheck disable=SC2064
  trap "exit ${SYSTEM_FAILURE_EXIT_CODE:-1}" ERR
  local base_image
  base_image="$(compgen -G "${libvirt_default_pool_path}/runner-base-*.qcow2" | sort -n -t - -k3,3 | tail -n 1)"

  if [[ -z ${base_image} ]]; then
    echo 'Base image not found...'
    exit "${SYSTEM_FAILURE_EXIT_CODE:-1}"
  fi

  qemu-img create -f qcow2 -b "${base_image}" -F qcow2 "${libvirt_default_pool_path}/$(vm_name).qcow2"
  virsh define <(sed "s/\$vm_name/$(vm_name)/" /usr/local/lib/libvirt-executor/domain_template.xml)
  virsh start "$(vm_name)"

  wait_for_ssh "$(vm_name)"
}

# https://docs.gitlab.com/runner/executors/custom.html#run
run() {
  local ip
  ip="$(wait_for_ssh "$(vm_name)")"
  ssh "${ip}" bash < "${1}" || exit "${BUILD_FAILURE_EXIT_CODE:-1}"
}

# https://docs.gitlab.com/runner/executors/custom.html#cleanup
cleanup() {
  virsh destroy "$(vm_name)" || true
  rm "${libvirt_default_pool_path}/$(vm_name).qcow2"
  virsh undefine "$(vm_name)"
}

case "${1:-}" in
  prepare)
    prepare
    ;;
  run)
    run "${2}" "${3}"
    ;;
  cleanup)
    cleanup
    ;;
  *)
    echo "Error invalid command: ${1:-}"
    exit 1;
esac