Function execExtension

packages/cli/src/util/extension/exec.ts:20–91

(
  client: Client,
  name: string,
  args: string[],
  cwd: string
)

 * error is thrown.
 */
export async function execExtension(
  client: Client,
  name: string,
  args: string[],
  cwd: string
): Promise<number> {
  const { debug, error } = output;
  const extensionCommand = `vercel-${name}`;

  const { packageJsonPath, lockfilePath } = await scanParentDirs(cwd);
  const baseFile = lockfilePath || packageJsonPath;
  let extensionPath: string | null = null;

  if (baseFile) {
    // Scan `node_modules/.bin` works for npm / pnpm / yarn v1
    // TOOD: add support for Yarn PnP
    extensionPath = await walkParentDirs({
      base: dirname(baseFile),
      start: cwd,
      filename: `node_modules/.bin/${extensionCommand}`,
    });
  }

  if (!extensionPath) {
    // Attempt global `$PATH` lookup
    extensionPath = which.sync(extensionCommand, { nothrow: true });
  }

  if (!extensionPath) {
    debug(`failed to find extension command with name "${extensionCommand}"`);
    throw new ENOENT(extensionCommand);
  }

  debug(`invoking extension: ${extensionPath}`);

  const proxy = createProxy(client);
  proxy.once('close', () => {
    debug(`extension proxy server shut down`);
  });

  const proxyUrl = await listen(proxy, { port: 0, host: '127.0.0.1' });
  const VERCEL_API = proxyUrl.href.replace(/\/$/, '');
  debug(`extension proxy server listening at ${VERCEL_API}`);
  let exitCode = 0;

  try {
    const result = await execa(extensionPath, args, {
      cwd,
      stdio: 'inherit',
      reject: false,
      env: {
        ...process.env,
        VERCEL_API,
        // TODO:
        //   VERCEL_SCOPE
        //   VERCEL_DEBUG
        //   VERCEL_HELP
      },