Function assertBuildContainerStorage

packages/container/src/storage-driver.ts:173–258

(
  log: (message: string) => void = () => {}
)

 * No-op outside the build container.
 */
export async function assertBuildContainerStorage(
  log: (message: string) => void = () => {}
): Promise<void> {
  if (!isBuildContainer()) {
    return;
  }
  if (readString(process.env.VERCEL_VCR_DOCKER_STORAGE_DRIVER)) {
    // Operator explicitly chose a driver; don't second-guess it.
    return;
  }

  const strict = Boolean(readString(process.env.VERCEL_VCR_STRICT_STORAGE));

  let storeInfo: BuildahStoreInfo | undefined;
  try {
    storeInfo = await readBuildahStoreInfo();
  } catch (err) {
    // `buildah info` itself failing (e.g. overlay can't init on this fs) is the
    // very condition we're reporting on; surface it but don't block by default.
    const message = `Could not verify buildah storage via \`buildah info\`: ${
      (err as Error).message
    }`;
    if (strict) {
      throw new Error(message);
    }
    log(message);
    return;
  }
  if (!storeInfo) {
    const message =
      'Could not verify buildah storage: `buildah info` returned no store data.';
    if (strict) {
      throw new Error(message);
    }
    log(message);
    return;
  }

  const problems: string[] = [];
  if (storeInfo.driver !== REQUIRED_BUILD_CONTAINER_DRIVER) {
    problems.push(
      `storage driver is "${storeInfo.driver}", expected ` +
        `"${REQUIRED_BUILD_CONTAINER_DRIVER}"`
    );
  }
  if (storeInfo.graphRoot !== BUILDAH_GRAPH_ROOT) {
    problems.push(
      `graphRoot is "${storeInfo.graphRoot}", expected the mounted ` +
        `volume "${BUILDAH_GRAPH_ROOT}"`
    );
  }
  // The volume is XFS; an overlay backing fs would mean we're on the cell
  // rootfs, not the mounted volume (overlay-on-overlay).
  if (storeInfo.backingFs && storeInfo.backingFs === 'overlayfs') {
    problems.push(
      `backing filesystem is "${storeInfo.backingFs}" (the overlay rootfs), ` +
        'not the mounted volume'
    );