ez_setup.py
70d781bd
 #!/usr/bin/env python
 
 """
 Setuptools bootstrapping installer.
 
 Run this 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
 import warnings
 
 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 = "12.0.5"
 DEFAULT_URL = "https://pypi.python.org/packages/source/s/setuptools/"
 
 
 def _python_cmd(*args):
     """
     Execute a command.
 
     Return True if the command succeeded.
     """
     args = (sys.executable,) + args
     return subprocess.call(args) == 0
 
 
 def _install(archive_filename, install_args=()):
     """Install Setuptools."""
     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):
     """Build Setuptools egg."""
     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):
     """
     Unzip filename to a temporary directory, set to the cwd.
 
     The unzipped target is cleaned up after.
     """
     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):
     """Download Setuptools."""
     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):
     """
     *deprecated* Download, install, and import Setuptools.
 
     Return None.
     """
     warnings.warn(
         "`use_setuptools` is deprecated. To enforce a specific "
         "version of setuptools, use `pkg_resources.require`.",
         DeprecationWarning,
     )
     to_dir = os.path.abspath(to_dir)
     rep_modules = 'pkg_resources', 'setuptools'
     imported = set(sys.modules).intersection(rep_modules)
     conflict_tmpl = 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})
         """)
     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 = conflict_tmpl.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.
 
     Powershell 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():
     """Determine if Powershell is available."""
     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, without connection authentication."""
     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.
 
     Returns list of command line arguments.
     """
     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())