docs: def serve(opts):
      """
      Run a light-weight HTTP server hosting previously mirrored resources
      """
      resources = _load(opts.resources, opts.output_dir)
      opts.output_dir = resources.output_dir  # allow resources.yaml to set default output_dir
      if not os.path.exists(opts.output_dir):
          sys.stderr.write("Resources dir '{}' not found.  Did you fetch?\n".format(opts.output_dir))
          return 1
      backend.PyPIResource.build_pypi_indexes(opts.output_dir)
      os.chdir(opts.output_dir)
  
      HTTPServer.allow_reuse_address = True
      httpd = HTTPServer((opts.host, opts.port), SimpleHTTPRequestHandler)
  
      if opts.ssl_cert:
          httpd.socket = ssl.wrap_socket(httpd.socket, certfile=opts.ssl_cert, server_side=True)
  
      print("Serving at: http{}://{}:{}/".format(
          's' if opts.ssl_cert else '', socket.gethostname(), opts.port))
      httpd.serve_forever()