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5586ba7643
This will hopefully make maintenance of venv documentation easier. For example, see commits a4f0d76af176 and 5764cc02244d. This patch has been reviewed by Vinaj Sajip, the maintainer of venv module.
410 lines
17 KiB
Python
410 lines
17 KiB
Python
"""
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Virtual environment (venv) package for Python. Based on PEP 405.
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Copyright (C) 2011-2014 Vinay Sajip.
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Licensed to the PSF under a contributor agreement.
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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 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, delete the contents of the environment directory if
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it already exists, before environment creation.
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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',
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'python%d.%d' % sys.version_info[:2],
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'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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# Issue 21197: create lib64 as a symlink to lib on 64-bit non-OS X POSIX
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if ((sys.maxsize > 2**32) and (os.name == 'posix') and
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(sys.platform != 'darwin')):
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link_path = os.path.join(env_dir, 'lib64')
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if not os.path.exists(link_path): # Issue #21643
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os.symlink('lib', link_path)
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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, relative_symlinks_ok=False):
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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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if relative_symlinks_ok:
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assert os.path.dirname(src) == os.path.dirname(dst)
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os.symlink(os.path.basename(src), dst)
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else:
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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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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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# Issue 18807: make copies if
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# symlinks are not wanted
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copier(context.env_exe, path, relative_symlinks_ok=True)
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if not os.path.islink(path):
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os.chmod(path, 0o755)
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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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if not os.path.exists(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, stderr=subprocess.STDOUT)
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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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"""Create a virtual environment in a directory."""
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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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