437 lines
18 KiB
Python
437 lines
18 KiB
Python
"""
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Virtual environment (venv) package for Python. Based on PEP 405.
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Copyright (C) 2011-2012 Vinay Sajip.
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Licensed to the PSF under a contributor agreement.
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usage: python -m venv [-h] [--system-site-packages] [--symlinks] [--clear]
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[--upgrade]
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ENV_DIR [ENV_DIR ...]
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Creates virtual Python environments in one or more target directories.
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positional arguments:
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ENV_DIR A directory to create the environment in.
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optional arguments:
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-h, --help show this help message and exit
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--system-site-packages
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Give the virtual environment access to the system
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site-packages dir.
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--symlinks Attempt to symlink rather than copy.
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--clear Delete the environment directory if it already exists.
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If not specified and the directory exists, an error is
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raised.
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--upgrade Upgrade the environment directory to use this version
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of Python, assuming Python has been upgraded in-place.
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--without-pip Skips installing or upgrading pip in the virtual
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environment (pip is bootstrapped by default)
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"""
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import logging
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import os
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import shutil
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import subprocess
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import sys
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import sysconfig
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import types
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logger = logging.getLogger(__name__)
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class EnvBuilder:
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"""
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This class exists to allow virtual environment creation to be
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customized. The constructor parameters determine the builder's
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behaviour when called upon to create a virtual environment.
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By default, the builder makes the system (global) site-packages dir
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*un*available to the created environment.
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If invoked using the Python -m option, the default is to use copying
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on Windows platforms but symlinks elsewhere. If instantiated some
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other way, the default is to *not* use symlinks.
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:param system_site_packages: If True, the system (global) site-packages
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dir is available to created environments.
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:param clear: If True and the target directory exists, it is deleted.
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Otherwise, if the target directory exists, an error is
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raised.
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:param symlinks: If True, attempt to symlink rather than copy files into
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virtual environment.
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:param upgrade: If True, upgrade an existing virtual environment.
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:param with_pip: If True, ensure pip is installed in the virtual
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environment
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"""
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def __init__(self, system_site_packages=False, clear=False,
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symlinks=False, upgrade=False, with_pip=False):
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self.system_site_packages = system_site_packages
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self.clear = clear
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self.symlinks = symlinks
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self.upgrade = upgrade
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self.with_pip = with_pip
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def create(self, env_dir):
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"""
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Create a virtual environment in a directory.
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:param env_dir: The target directory to create an environment in.
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"""
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env_dir = os.path.abspath(env_dir)
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context = self.ensure_directories(env_dir)
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self.create_configuration(context)
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self.setup_python(context)
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if self.with_pip:
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self._setup_pip(context)
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if not self.upgrade:
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self.setup_scripts(context)
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self.post_setup(context)
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def clear_directory(self, path):
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for fn in os.listdir(path):
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fn = os.path.join(path, fn)
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if os.path.islink(fn) or os.path.isfile(fn):
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os.remove(fn)
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elif os.path.isdir(fn):
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shutil.rmtree(fn)
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def ensure_directories(self, env_dir):
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"""
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Create the directories for the environment.
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Returns a context object which holds paths in the environment,
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for use by subsequent logic.
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"""
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def create_if_needed(d):
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if not os.path.exists(d):
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os.makedirs(d)
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elif os.path.islink(d) or os.path.isfile(d):
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raise ValueError('Unable to create directory %r' % d)
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if os.path.exists(env_dir) and self.clear:
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self.clear_directory(env_dir)
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context = types.SimpleNamespace()
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context.env_dir = env_dir
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context.env_name = os.path.split(env_dir)[1]
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context.prompt = '(%s) ' % context.env_name
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create_if_needed(env_dir)
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env = os.environ
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if sys.platform == 'darwin' and '__PYVENV_LAUNCHER__' in env:
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executable = os.environ['__PYVENV_LAUNCHER__']
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else:
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executable = sys.executable
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dirname, exename = os.path.split(os.path.abspath(executable))
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context.executable = executable
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context.python_dir = dirname
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context.python_exe = exename
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if sys.platform == 'win32':
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binname = 'Scripts'
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incpath = 'Include'
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libpath = os.path.join(env_dir, 'Lib', 'site-packages')
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else:
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binname = 'bin'
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incpath = 'include'
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libpath = os.path.join(env_dir, 'lib', 'python%d.%d' % sys.version_info[:2], 'site-packages')
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context.inc_path = path = os.path.join(env_dir, incpath)
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create_if_needed(path)
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create_if_needed(libpath)
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context.bin_path = binpath = os.path.join(env_dir, binname)
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context.bin_name = binname
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context.env_exe = os.path.join(binpath, exename)
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create_if_needed(binpath)
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return context
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def create_configuration(self, context):
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"""
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Create a configuration file indicating where the environment's Python
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was copied from, and whether the system site-packages should be made
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available in the environment.
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:param context: The information for the environment creation request
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being processed.
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"""
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context.cfg_path = path = os.path.join(context.env_dir, 'pyvenv.cfg')
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with open(path, 'w', encoding='utf-8') as f:
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f.write('home = %s\n' % context.python_dir)
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if self.system_site_packages:
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incl = 'true'
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else:
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incl = 'false'
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f.write('include-system-site-packages = %s\n' % incl)
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f.write('version = %d.%d.%d\n' % sys.version_info[:3])
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if os.name == 'nt':
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def include_binary(self, f):
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if f.endswith(('.pyd', '.dll')):
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result = True
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else:
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result = f.startswith('python') and f.endswith('.exe')
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return result
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def symlink_or_copy(self, src, dst):
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"""
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Try symlinking a file, and if that fails, fall back to copying.
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"""
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force_copy = not self.symlinks
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if not force_copy:
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try:
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if not os.path.islink(dst): # can't link to itself!
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os.symlink(src, dst)
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except Exception: # may need to use a more specific exception
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logger.warning('Unable to symlink %r to %r', src, dst)
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force_copy = True
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if force_copy:
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shutil.copyfile(src, dst)
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def setup_python(self, context):
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"""
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Set up a Python executable in the environment.
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:param context: The information for the environment creation request
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being processed.
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"""
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binpath = context.bin_path
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exename = context.python_exe
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path = context.env_exe
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copier = self.symlink_or_copy
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copier(context.executable, path)
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dirname = context.python_dir
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if os.name != 'nt':
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if not os.path.islink(path):
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os.chmod(path, 0o755)
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for suffix in ('python', 'python3'):
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path = os.path.join(binpath, suffix)
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if not os.path.exists(path):
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os.symlink(exename, path)
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else:
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subdir = 'DLLs'
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include = self.include_binary
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files = [f for f in os.listdir(dirname) if include(f)]
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for f in files:
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src = os.path.join(dirname, f)
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dst = os.path.join(binpath, f)
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if dst != context.env_exe: # already done, above
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copier(src, dst)
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dirname = os.path.join(dirname, subdir)
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if os.path.isdir(dirname):
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files = [f for f in os.listdir(dirname) if include(f)]
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for f in files:
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src = os.path.join(dirname, f)
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dst = os.path.join(binpath, f)
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copier(src, dst)
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# copy init.tcl over
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for root, dirs, files in os.walk(context.python_dir):
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if 'init.tcl' in files:
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tcldir = os.path.basename(root)
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tcldir = os.path.join(context.env_dir, 'Lib', tcldir)
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os.makedirs(tcldir)
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src = os.path.join(root, 'init.tcl')
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dst = os.path.join(tcldir, 'init.tcl')
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shutil.copyfile(src, dst)
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break
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def _setup_pip(self, context):
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"""Installs or upgrades pip in a virtual environment"""
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# We run ensurepip in isolated mode to avoid side effects from
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# environment vars, the current directory and anything else
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# intended for the global Python environment
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cmd = [context.env_exe, '-Im', 'ensurepip', '--upgrade',
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'--default-pip']
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subprocess.check_output(cmd)
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def setup_scripts(self, context):
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"""
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Set up scripts into the created environment from a directory.
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This method installs the default scripts into the environment
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being created. You can prevent the default installation by overriding
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this method if you really need to, or if you need to specify
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a different location for the scripts to install. By default, the
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'scripts' directory in the venv package is used as the source of
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scripts to install.
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"""
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path = os.path.abspath(os.path.dirname(__file__))
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path = os.path.join(path, 'scripts')
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self.install_scripts(context, path)
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def post_setup(self, context):
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"""
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Hook for post-setup modification of the venv. Subclasses may install
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additional packages or scripts here, add activation shell scripts, etc.
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:param context: The information for the environment creation request
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being processed.
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"""
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pass
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def replace_variables(self, text, context):
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"""
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Replace variable placeholders in script text with context-specific
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variables.
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Return the text passed in , but with variables replaced.
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:param text: The text in which to replace placeholder variables.
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:param context: The information for the environment creation request
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being processed.
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"""
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text = text.replace('__VENV_DIR__', context.env_dir)
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text = text.replace('__VENV_NAME__', context.env_name)
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text = text.replace('__VENV_PROMPT__', context.prompt)
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text = text.replace('__VENV_BIN_NAME__', context.bin_name)
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text = text.replace('__VENV_PYTHON__', context.env_exe)
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return text
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def install_scripts(self, context, path):
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"""
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Install scripts into the created environment from a directory.
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:param context: The information for the environment creation request
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being processed.
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:param path: Absolute pathname of a directory containing script.
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Scripts in the 'common' subdirectory of this directory,
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and those in the directory named for the platform
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being run on, are installed in the created environment.
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Placeholder variables are replaced with environment-
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specific values.
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"""
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binpath = context.bin_path
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plen = len(path)
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for root, dirs, files in os.walk(path):
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if root == path: # at top-level, remove irrelevant dirs
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for d in dirs[:]:
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if d not in ('common', os.name):
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dirs.remove(d)
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continue # ignore files in top level
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for f in files:
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srcfile = os.path.join(root, f)
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suffix = root[plen:].split(os.sep)[2:]
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if not suffix:
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dstdir = binpath
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else:
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dstdir = os.path.join(binpath, *suffix)
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if not os.path.exists(dstdir):
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os.makedirs(dstdir)
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dstfile = os.path.join(dstdir, f)
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with open(srcfile, 'rb') as f:
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data = f.read()
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if srcfile.endswith('.exe'):
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mode = 'wb'
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else:
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mode = 'w'
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try:
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data = data.decode('utf-8')
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data = self.replace_variables(data, context)
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except UnicodeDecodeError as e:
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data = None
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logger.warning('unable to copy script %r, '
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'may be binary: %s', srcfile, e)
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if data is not None:
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with open(dstfile, mode) as f:
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f.write(data)
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shutil.copymode(srcfile, dstfile)
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def create(env_dir, system_site_packages=False, clear=False,
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symlinks=False, with_pip=False):
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"""
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Create a virtual environment in a directory.
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By default, makes the system (global) site-packages dir *un*available to
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the created environment, and uses copying rather than symlinking for files
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obtained from the source Python installation.
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:param env_dir: The target directory to create an environment in.
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:param system_site_packages: If True, the system (global) site-packages
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dir is available to the environment.
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:param clear: If True and the target directory exists, it is deleted.
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Otherwise, if the target directory exists, an error is
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raised.
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:param symlinks: If True, attempt to symlink rather than copy files into
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virtual environment.
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:param with_pip: If True, ensure pip is installed in the virtual
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environment
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"""
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builder = EnvBuilder(system_site_packages=system_site_packages,
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clear=clear, symlinks=symlinks, with_pip=with_pip)
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builder.create(env_dir)
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def main(args=None):
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compatible = True
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if sys.version_info < (3, 3):
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compatible = False
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elif not hasattr(sys, 'base_prefix'):
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compatible = False
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if not compatible:
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raise ValueError('This script is only for use with Python >= 3.3')
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else:
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import argparse
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parser = argparse.ArgumentParser(prog=__name__,
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description='Creates virtual Python '
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'environments in one or '
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'more target '
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'directories.',
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epilog='Once an environment has been '
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'created, you may wish to '
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'activate it, e.g. by '
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'sourcing an activate script '
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'in its bin directory.')
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parser.add_argument('dirs', metavar='ENV_DIR', nargs='+',
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help='A directory to create the environment in.')
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parser.add_argument('--system-site-packages', default=False,
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action='store_true', dest='system_site',
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help='Give the virtual environment access to the '
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'system site-packages dir.')
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if os.name == 'nt':
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use_symlinks = False
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else:
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use_symlinks = True
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group = parser.add_mutually_exclusive_group()
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group.add_argument('--symlinks', default=use_symlinks,
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action='store_true', dest='symlinks',
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help='Try to use symlinks rather than copies, '
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'when symlinks are not the default for '
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'the platform.')
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group.add_argument('--copies', default=not use_symlinks,
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action='store_false', dest='symlinks',
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help='Try to use copies rather than symlinks, '
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'even when symlinks are the default for '
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'the platform.')
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parser.add_argument('--clear', default=False, action='store_true',
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dest='clear', help='Delete the contents of the '
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'environment directory if it '
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'already exists, before '
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'environment creation.')
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parser.add_argument('--upgrade', default=False, action='store_true',
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dest='upgrade', help='Upgrade the environment '
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'directory to use this version '
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'of Python, assuming Python '
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'has been upgraded in-place.')
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parser.add_argument('--without-pip', dest='with_pip',
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default=True, action='store_false',
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help='Skips installing or upgrading pip in the '
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'virtual environment (pip is bootstrapped '
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'by default)')
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options = parser.parse_args(args)
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if options.upgrade and options.clear:
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raise ValueError('you cannot supply --upgrade and --clear together.')
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builder = EnvBuilder(system_site_packages=options.system_site,
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clear=options.clear,
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symlinks=options.symlinks,
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upgrade=options.upgrade,
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with_pip=options.with_pip)
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for d in options.dirs:
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builder.create(d)
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if __name__ == '__main__':
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rc = 1
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try:
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main()
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rc = 0
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except Exception as e:
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print('Error: %s' % e, file=sys.stderr)
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sys.exit(rc)
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