Add ez_setup.py (from setuptools 18.3.2)

+#!/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 = "18.3.2"
+DEFAULT_URL = "https://pypi.python.org/packages/source/s/setuptools/"
+DEFAULT_SAVE_DIR = os.curdir
+
+
+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=DEFAULT_SAVE_DIR, download_delay=15):
+    """
+    Ensure that a setuptools version is installed.
+
+    Return None. Raise SystemExit if the requested version
+    or later cannot be installed.
+    """
+    to_dir = os.path.abspath(to_dir)
+
+    # prior to importing, capture the module state for
+    # representative modules.
+    rep_modules = 'pkg_resources', 'setuptools'
+    imported = set(sys.modules).intersection(rep_modules)
+
+    try:
+        import pkg_resources
+        pkg_resources.require("setuptools>=" + version)
+        # a suitable version is already installed
+        return
+    except ImportError:
+        # pkg_resources not available; setuptools is not installed; download
+        pass
+    except pkg_resources.DistributionNotFound:
+        # no version of setuptools was found; allow download
+        pass
+    except pkg_resources.VersionConflict as VC_err:
+        if imported:
+            _conflict_bail(VC_err, version)
+
+        # otherwise, unload pkg_resources to allow the downloaded version to
+        #  take precedence.
+        del pkg_resources
+        _unload_pkg_resources()
+
+    return _do_download(version, download_base, to_dir, download_delay)
+
+
+def _conflict_bail(VC_err, version):
+    """
+    Setuptools was imported prior to invocation, so it is
+    unsafe to unload it. Bail out.
+    """
+    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})
+        """)
+    msg = conflict_tmpl.format(**locals())
+    sys.stderr.write(msg)
+    sys.exit(2)
+
+
+def _unload_pkg_resources():
+    del_modules = [
+        name for name in sys.modules
+        if name.startswith('pkg_resources')
+    ]
+    for mod_name in del_modules:
+        del sys.modules[mod_name]
+
+
+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=DEFAULT_SAVE_DIR, 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,
+    )
+    parser.add_option(
+    	'--to-dir',
+    	help="Directory to save (and re-use) package",
+    	default=DEFAULT_SAVE_DIR,
+    )
+    options, args = parser.parse_args()
+    # positional arguments are ignored
+    return options
+
+
+def _download_args(options):
+	"""Return args for download_setuptools function from cmdline args."""
+	return dict(
+		version=options.version,
+		download_base=options.download_base,
+		downloader_factory=options.downloader_factory,
+		to_dir=options.to_dir,
+	)
+
+
+def main():
+    """Install or upgrade setuptools and EasyInstall."""
+    options = _parse_args()
+    archive = download_setuptools(**_download_args(options))
+    return _install(archive, _build_install_args(options))
+
+if __name__ == '__main__':
+    sys.exit(main())