Function assertDockerAvailable

packages/container/src/dev.ts:341–365

* Verify the Docker daemon is installed and reachable before doing any build * or run work, so the user gets one clear message instead of a cryptic exit * code from whichever Docker command happened to run first. `docker info` * connects to the daemon and exits non-zero (125) when it can't.

(out: DevOutput)

 * connects to the daemon and exits non-zero (125) when it can't.
 */
async function assertDockerAvailable(out: DevOutput): Promise<void> {
  try {
    await runForwarded(
      'docker',
      ['info', '--format', '{{.ServerVersion}}'],
      out,
      {
        quiet: true,
      }
    );
  } catch (err) {
    const message = (err as Error).message ?? '';
    if (/command not found/i.test(message)) {
      throw new Error(
        'Docker is required for `vercel dev` with containers, but the ' +
          '`docker` command was not found. Install Docker and ensure it is ' +
          'on your PATH.'
      );
    }
    throw new Error(
      'Could not connect to the Docker daemon. Start Docker (e.g. open ' +
        'Docker Desktop) and run `vercel dev` again.'
    );
  }
}

/**
 * Build a helpful error for a `docker run` that exited before the container