text: #!/usr/bin/env python
  """Bootstrap setuptools installation
  
  To use setuptools in your package's setup.py, include this
  file in the same directory and add this to the top of your setup.py::
  
      from ez_setup import use_setuptools
      use_setuptools()
  
  To require a specific version of setuptools, set a download
  mirror, or use an alternate download directory, simply supply
  the appropriate options to ``use_setuptools()``.
  
  This file can also be run as a script to install or upgrade setuptools.
  """
  import os
  import shutil
  import sys
  import tempfile
  import zipfile
  import optparse
  import subprocess
  import platform
  import textwrap
  import contextlib
  
  from distutils import log
  
  try:
      from urllib.request import urlopen
  except ImportError:
      from urllib2 import urlopen
  
  try:
      from site import USER_SITE
  except ImportError:
      USER_SITE = None
  
  DEFAULT_VERSION = "12.0.4"
  DEFAULT_URL = "https://pypi.python.org/packages/source/s/setuptools/"
  
  def _python_cmd(*args):
      """
      Return True if the command succeeded.
      """
      args = (sys.executable,) + args
      return subprocess.call(args) == 0
  
  
  def _install(archive_filename, install_args=()):
      with archive_context(archive_filename):
          # installing
          log.warn('Installing Setuptools')
          if not _python_cmd('setup.py', 'install', *install_args):
              log.warn('Something went wrong during the installation.')
              log.warn('See the error message above.')
              # exitcode will be 2
              return 2
  
  
  def _build_egg(egg, archive_filename, to_dir):
      with archive_context(archive_filename):
          # building an egg
          log.warn('Building a Setuptools egg in %s', to_dir)
          _python_cmd('setup.py', '-q', 'bdist_egg', '--dist-dir', to_dir)
      # returning the result
      log.warn(egg)
      if not os.path.exists(egg):
          raise IOError('Could not build the egg.')
  
  
  class ContextualZipFile(zipfile.ZipFile):
      """
      Supplement ZipFile class to support context manager for Python 2.6
      """
  
      def __enter__(self):
          return self
  
      def __exit__(self, type, value, traceback):
          self.close()
  
      def __new__(cls, *args, **kwargs):
          """
          Construct a ZipFile or ContextualZipFile as appropriate
          """
          if hasattr(zipfile.ZipFile, '__exit__'):
              return zipfile.ZipFile(*args, **kwargs)
          return super(ContextualZipFile, cls).__new__(cls)
  
  
  @contextlib.contextmanager
  def archive_context(filename):
      # extracting the archive
      tmpdir = tempfile.mkdtemp()
      log.warn('Extracting in %s', tmpdir)
      old_wd = os.getcwd()
      try:
          os.chdir(tmpdir)
          with ContextualZipFile(filename) as archive:
              archive.extractall()
  
          # going in the directory
          subdir = os.path.join(tmpdir, os.listdir(tmpdir)[0])
          os.chdir(subdir)
          log.warn('Now working in %s', subdir)
          yield
  
      finally:
          os.chdir(old_wd)
          shutil.rmtree(tmpdir)
  
  
  def _do_download(version, download_base, to_dir, download_delay):
      egg = os.path.join(to_dir, 'setuptools-%s-py%d.%d.egg'
                         % (version, sys.version_info[0], sys.version_info[1]))
      if not os.path.exists(egg):
          archive = download_setuptools(version, download_base,
                                        to_dir, download_delay)
          _build_egg(egg, archive, to_dir)
      sys.path.insert(0, egg)
  
      # Remove previously-imported pkg_resources if present (see
      # https://bitbucket.org/pypa/setuptools/pull-request/7/ for details).
      if 'pkg_resources' in sys.modules:
          del sys.modules['pkg_resources']
  
      import setuptools
      setuptools.bootstrap_install_from = egg
  
  
  def use_setuptools(version=DEFAULT_VERSION, download_base=DEFAULT_URL,
          to_dir=os.curdir, download_delay=15):
      to_dir = os.path.abspath(to_dir)
      rep_modules = 'pkg_resources', 'setuptools'
      imported = set(sys.modules).intersection(rep_modules)
      try:
          import pkg_resources
      except ImportError:
          return _do_download(version, download_base, to_dir, download_delay)
      try:
          pkg_resources.require("setuptools>=" + version)
          return
      except pkg_resources.DistributionNotFound:
          return _do_download(version, download_base, to_dir, download_delay)
      except pkg_resources.VersionConflict as VC_err:
          if imported:
              msg = textwrap.dedent("""
                  The required version of setuptools (>={version}) is not available,
                  and can't be installed while this script is running. Please
                  install a more recent version first, using
                  'easy_install -U setuptools'.
  
                  (Currently using {VC_err.args[0]!r})
                  """).format(VC_err=VC_err, version=version)
              sys.stderr.write(msg)
              sys.exit(2)
  
          # otherwise, reload ok
          del pkg_resources, sys.modules['pkg_resources']
          return _do_download(version, download_base, to_dir, download_delay)
  
  def _clean_check(cmd, target):
      """
      Run the command to download target. If the command fails, clean up before
      re-raising the error.
      """
      try:
          subprocess.check_call(cmd)
      except subprocess.CalledProcessError:
          if os.access(target, os.F_OK):
              os.unlink(target)
          raise
  
  def download_file_powershell(url, target):
      """
      Download the file at url to target using Powershell (which will validate
      trust). Raise an exception if the command cannot complete.
      """
      target = os.path.abspath(target)
      ps_cmd = (
          "[System.Net.WebRequest]::DefaultWebProxy.Credentials = "
          "[System.Net.CredentialCache]::DefaultCredentials; "
          "(new-object System.Net.WebClient).DownloadFile(%(url)r, %(target)r)"
          % vars()
      )
      cmd = [
          'powershell',
          '-Command',
          ps_cmd,
      ]
      _clean_check(cmd, target)
  
  def has_powershell():
      if platform.system() != 'Windows':
          return False
      cmd = ['powershell', '-Command', 'echo test']
      with open(os.path.devnull, 'wb') as devnull:
          try:
              subprocess.check_call(cmd, stdout=devnull, stderr=devnull)
          except Exception:
              return False
      return True
  
  download_file_powershell.viable = has_powershell
  
  def download_file_curl(url, target):
      cmd = ['curl', url, '--silent', '--output', target]
      _clean_check(cmd, target)
  
  def has_curl():
      cmd = ['curl', '--version']
      with open(os.path.devnull, 'wb') as devnull:
          try:
              subprocess.check_call(cmd, stdout=devnull, stderr=devnull)
          except Exception:
              return False
      return True
  
  download_file_curl.viable = has_curl
  
  def download_file_wget(url, target):
      cmd = ['wget', url, '--quiet', '--output-document', target]
      _clean_check(cmd, target)
  
  def has_wget():
      cmd = ['wget', '--version']
      with open(os.path.devnull, 'wb') as devnull:
          try:
              subprocess.check_call(cmd, stdout=devnull, stderr=devnull)
          except Exception:
              return False
      return True
  
  download_file_wget.viable = has_wget
  
  def download_file_insecure(url, target):
      """
      Use Python to download the file, even though it cannot authenticate the
      connection.
      """
      src = urlopen(url)
      try:
          # Read all the data in one block.
          data = src.read()
      finally:
          src.close()
  
      # Write all the data in one block to avoid creating a partial file.
      with open(target, "wb") as dst:
          dst.write(data)
  
  download_file_insecure.viable = lambda: True
  
  def get_best_downloader():
      downloaders = (
          download_file_powershell,
          download_file_curl,
          download_file_wget,
          download_file_insecure,
      )
      viable_downloaders = (dl for dl in downloaders if dl.viable())
      return next(viable_downloaders, None)
  
  def download_setuptools(version=DEFAULT_VERSION, download_base=DEFAULT_URL,
          to_dir=os.curdir, delay=15, downloader_factory=get_best_downloader):
      """
      Download setuptools from a specified location and return its filename
  
      `version` should be a valid setuptools version number that is available
      as an sdist for download under the `download_base` URL (which should end
      with a '/'). `to_dir` is the directory where the egg will be downloaded.
      `delay` is the number of seconds to pause before an actual download
      attempt.
  
      ``downloader_factory`` should be a function taking no arguments and
      returning a function for downloading a URL to a target.
      """
      # making sure we use the absolute path
      to_dir = os.path.abspath(to_dir)
      zip_name = "setuptools-%s.zip" % version
      url = download_base + zip_name
      saveto = os.path.join(to_dir, zip_name)
      if not os.path.exists(saveto):  # Avoid repeated downloads
          log.warn("Downloading %s", url)
          downloader = downloader_factory()
          downloader(url, saveto)
      return os.path.realpath(saveto)
  
  def _build_install_args(options):
      """
      Build the arguments to 'python setup.py install' on the setuptools package
      """
      return ['--user'] if options.user_install else []
  
  def _parse_args():
      """
      Parse the command line for options
      """
      parser = optparse.OptionParser()
      parser.add_option(
          '--user', dest='user_install', action='store_true', default=False,
          help='install in user site package (requires Python 2.6 or later)')
      parser.add_option(
          '--download-base', dest='download_base', metavar="URL",
          default=DEFAULT_URL,
          help='alternative URL from where to download the setuptools package')
      parser.add_option(
          '--insecure', dest='downloader_factory', action='store_const',
          const=lambda: download_file_insecure, default=get_best_downloader,
          help='Use internal, non-validating downloader'
      )
      parser.add_option(
          '--version', help="Specify which version to download",
          default=DEFAULT_VERSION,
      )
      options, args = parser.parse_args()
      # positional arguments are ignored
      return options
  
  def main():
      """Install or upgrade setuptools and EasyInstall"""
      options = _parse_args()
      archive = download_setuptools(
          version=options.version,
          download_base=options.download_base,
          downloader_factory=options.downloader_factory,
      )
      return _install(archive, _build_install_args(options))
  
  if __name__ == '__main__':
      sys.exit(main())