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Diffstat (limited to 'Lib/venv/__init__.py')
| -rw-r--r-- | Lib/venv/__init__.py | 395 |
1 files changed, 395 insertions, 0 deletions
diff --git a/Lib/venv/__init__.py b/Lib/venv/__init__.py new file mode 100644 index 0000000000..3606370e86 --- /dev/null +++ b/Lib/venv/__init__.py @@ -0,0 +1,395 @@ +""" +Virtual environment (venv) package for Python. Based on PEP 405. + +Copyright (C) 2011-2012 Vinay Sajip. +Licensed to the PSF under a contributor agreement. + +usage: python -m venv [-h] [--system-site-packages] [--symlinks] [--clear] + [--upgrade] + ENV_DIR [ENV_DIR ...] + +Creates virtual Python environments in one or more target directories. + +positional arguments: + ENV_DIR A directory to create the environment in. + +optional arguments: + -h, --help show this help message and exit + --system-site-packages + Give the virtual environment access to the system + site-packages dir. + --symlinks Attempt to symlink rather than copy. + --clear Delete the environment directory if it already exists. + If not specified and the directory exists, an error is + raised. + --upgrade Upgrade the environment directory to use this version + of Python, assuming Python has been upgraded in-place. +""" +import logging +import os +import shutil +import sys +import sysconfig +import types + +logger = logging.getLogger(__name__) + + +class EnvBuilder: + """ + This class exists to allow virtual environment creation to be + customized. The constructor parameters determine the builder's + behaviour when called upon to create a virtual environment. + + By default, the builder makes the system (global) site-packages dir + *un*available to the created environment. + + If invoked using the Python -m option, the default is to use copying + on Windows platforms but symlinks elsewhere. If instantiated some + other way, the default is to *not* use symlinks. + + :param system_site_packages: If True, the system (global) site-packages + dir is available to created environments. + :param clear: If True and the target directory exists, it is deleted. + Otherwise, if the target directory exists, an error is + raised. + :param symlinks: If True, attempt to symlink rather than copy files into + virtual environment. + :param upgrade: If True, upgrade an existing virtual environment. + """ + + def __init__(self, system_site_packages=False, clear=False, + symlinks=False, upgrade=False): + self.system_site_packages = system_site_packages + self.clear = clear + self.symlinks = symlinks + self.upgrade = upgrade + + def create(self, env_dir): + """ + Create a virtual environment in a directory. + + :param env_dir: The target directory to create an environment in. + + """ + env_dir = os.path.abspath(env_dir) + context = self.ensure_directories(env_dir) + self.create_configuration(context) + self.setup_python(context) + if not self.upgrade: + self.setup_scripts(context) + self.post_setup(context) + + def ensure_directories(self, env_dir): + """ + Create the directories for the environment. + + Returns a context object which holds paths in the environment, + for use by subsequent logic. + """ + + def create_if_needed(d): + if not os.path.exists(d): + os.makedirs(d) + + if os.path.exists(env_dir) and not (self.clear or self.upgrade): + raise ValueError('Directory exists: %s' % env_dir) + if os.path.exists(env_dir) and self.clear: + shutil.rmtree(env_dir) + context = types.SimpleNamespace() + context.env_dir = env_dir + context.env_name = os.path.split(env_dir)[1] + context.prompt = '(%s) ' % context.env_name + create_if_needed(env_dir) + env = os.environ + if sys.platform == 'darwin' and '__PYVENV_LAUNCHER__' in env: + executable = os.environ['__PYVENV_LAUNCHER__'] + else: + executable = sys.executable + dirname, exename = os.path.split(os.path.abspath(executable)) + context.executable = executable + context.python_dir = dirname + context.python_exe = exename + if sys.platform == 'win32': + binname = 'Scripts' + incpath = 'Include' + libpath = os.path.join(env_dir, 'Lib', 'site-packages') + else: + binname = 'bin' + incpath = 'include' + libpath = os.path.join(env_dir, 'lib', 'python%d.%d' % sys.version_info[:2], 'site-packages') + context.inc_path = path = os.path.join(env_dir, incpath) + create_if_needed(path) + create_if_needed(libpath) + context.bin_path = binpath = os.path.join(env_dir, binname) + context.bin_name = binname + context.env_exe = os.path.join(binpath, exename) + create_if_needed(binpath) + return context + + def create_configuration(self, context): + """ + Create a configuration file indicating where the environment's Python + was copied from, and whether the system site-packages should be made + available in the environment. + + :param context: The information for the environment creation request + being processed. + """ + context.cfg_path = path = os.path.join(context.env_dir, 'pyvenv.cfg') + with open(path, 'w', encoding='utf-8') as f: + f.write('home = %s\n' % context.python_dir) + if self.system_site_packages: + incl = 'true' + else: + incl = 'false' + f.write('include-system-site-packages = %s\n' % incl) + f.write('version = %d.%d.%d\n' % sys.version_info[:3]) + + if os.name == 'nt': + def include_binary(self, f): + if f.endswith(('.pyd', '.dll')): + result = True + else: + result = f.startswith('python') and f.endswith('.exe') + return result + + def symlink_or_copy(self, src, dst): + """ + Try symlinking a file, and if that fails, fall back to copying. + """ + force_copy = not self.symlinks + if not force_copy: + try: + if not os.path.islink(dst): # can't link to itself! + os.symlink(src, dst) + except Exception: # may need to use a more specific exception + logger.warning('Unable to symlink %r to %r', src, dst) + force_copy = True + if force_copy: + shutil.copyfile(src, dst) + + def setup_python(self, context): + """ + Set up a Python executable in the environment. + + :param context: The information for the environment creation request + being processed. + """ + binpath = context.bin_path + exename = context.python_exe + path = context.env_exe + copier = self.symlink_or_copy + copier(context.executable, path) + dirname = context.python_dir + if os.name != 'nt': + if not os.path.islink(path): + os.chmod(path, 0o755) + for suffix in ('python', 'python3'): + path = os.path.join(binpath, suffix) + if not os.path.exists(path): + os.symlink(exename, path) + else: + subdir = 'DLLs' + include = self.include_binary + files = [f for f in os.listdir(dirname) if include(f)] + for f in files: + src = os.path.join(dirname, f) + dst = os.path.join(binpath, f) + if dst != context.env_exe: # already done, above + copier(src, dst) + dirname = os.path.join(dirname, subdir) + if os.path.isdir(dirname): + files = [f for f in os.listdir(dirname) if include(f)] + for f in files: + src = os.path.join(dirname, f) + dst = os.path.join(binpath, f) + copier(src, dst) + # copy init.tcl over + for root, dirs, files in os.walk(context.python_dir): + if 'init.tcl' in files: + tcldir = os.path.basename(root) + tcldir = os.path.join(context.env_dir, 'Lib', tcldir) + os.makedirs(tcldir) + src = os.path.join(root, 'init.tcl') + dst = os.path.join(tcldir, 'init.tcl') + shutil.copyfile(src, dst) + break + + def setup_scripts(self, context): + """ + Set up scripts into the created environment from a directory. + + This method installs the default scripts into the environment + being created. You can prevent the default installation by overriding + this method if you really need to, or if you need to specify + a different location for the scripts to install. By default, the + 'scripts' directory in the venv package is used as the source of + scripts to install. + """ + path = os.path.abspath(os.path.dirname(__file__)) + path = os.path.join(path, 'scripts') + self.install_scripts(context, path) + + def post_setup(self, context): + """ + Hook for post-setup modification of the venv. Subclasses may install + additional packages or scripts here, add activation shell scripts, etc. + + :param context: The information for the environment creation request + being processed. + """ + pass + + def replace_variables(self, text, context): + """ + Replace variable placeholders in script text with context-specific + variables. + + Return the text passed in , but with variables replaced. + + :param text: The text in which to replace placeholder variables. + :param context: The information for the environment creation request + being processed. + """ + text = text.replace('__VENV_DIR__', context.env_dir) + text = text.replace('__VENV_NAME__', context.prompt) + text = text.replace('__VENV_BIN_NAME__', context.bin_name) + text = text.replace('__VENV_PYTHON__', context.env_exe) + return text + + def install_scripts(self, context, path): + """ + Install scripts into the created environment from a directory. + + :param context: The information for the environment creation request + being processed. + :param path: Absolute pathname of a directory containing script. + Scripts in the 'common' subdirectory of this directory, + and those in the directory named for the platform + being run on, are installed in the created environment. + Placeholder variables are replaced with environment- + specific values. + """ + binpath = context.bin_path + plen = len(path) + for root, dirs, files in os.walk(path): + if root == path: # at top-level, remove irrelevant dirs + for d in dirs[:]: + if d not in ('common', os.name): + dirs.remove(d) + continue # ignore files in top level + for f in files: + srcfile = os.path.join(root, f) + suffix = root[plen:].split(os.sep)[2:] + if not suffix: + dstdir = binpath + else: + dstdir = os.path.join(binpath, *suffix) + if not os.path.exists(dstdir): + os.makedirs(dstdir) + dstfile = os.path.join(dstdir, f) + with open(srcfile, 'rb') as f: + data = f.read() + if srcfile.endswith('.exe'): + mode = 'wb' + else: + mode = 'w' + try: + data = data.decode('utf-8') + data = self.replace_variables(data, context) + except UnicodeDecodeError as e: + data = None + logger.warning('unable to copy script %r, ' + 'may be binary: %s', srcfile, e) + if data is not None: + with open(dstfile, mode) as f: + f.write(data) + shutil.copymode(srcfile, dstfile) + + +def create(env_dir, system_site_packages=False, clear=False, symlinks=False): + """ + Create a virtual environment in a directory. + + By default, makes the system (global) site-packages dir *un*available to + the created environment, and uses copying rather than symlinking for files + obtained from the source Python installation. + + :param env_dir: The target directory to create an environment in. + :param system_site_packages: If True, the system (global) site-packages + dir is available to the environment. + :param clear: If True and the target directory exists, it is deleted. + Otherwise, if the target directory exists, an error is + raised. + :param symlinks: If True, attempt to symlink rather than copy files into + virtual environment. + """ + builder = EnvBuilder(system_site_packages=system_site_packages, + clear=clear, symlinks=symlinks) + builder.create(env_dir) + +def main(args=None): + compatible = True + if sys.version_info < (3, 3): + compatible = False + elif not hasattr(sys, 'base_prefix'): + compatible = False + if not compatible: + raise ValueError('This script is only for use with Python >= 3.3') + else: + import argparse + + parser = argparse.ArgumentParser(prog=__name__, + description='Creates virtual Python ' + 'environments in one or ' + 'more target ' + 'directories.', + epilog='Once an environment has been ' + 'created, you may wish to ' + 'activate it, e.g. by ' + 'sourcing an activate script ' + 'in its bin directory.') + parser.add_argument('dirs', metavar='ENV_DIR', nargs='+', + help='A directory to create the environment in.') + parser.add_argument('--system-site-packages', default=False, + action='store_true', dest='system_site', + help='Give the virtual environment access to the ' + 'system site-packages dir.') + if os.name == 'nt': + use_symlinks = False + else: + use_symlinks = True + parser.add_argument('--symlinks', default=use_symlinks, + action='store_true', dest='symlinks', + help='Try to use symlinks rather than copies, ' + 'when symlinks are not the default for ' + 'the platform.') + parser.add_argument('--clear', default=False, action='store_true', + dest='clear', help='Delete the environment ' + 'directory if it already ' + 'exists. If not specified and ' + 'the directory exists, an error' + ' is raised.') + parser.add_argument('--upgrade', default=False, action='store_true', + dest='upgrade', help='Upgrade the environment ' + 'directory to use this version ' + 'of Python, assuming Python ' + 'has been upgraded in-place.') + options = parser.parse_args(args) + if options.upgrade and options.clear: + raise ValueError('you cannot supply --upgrade and --clear together.') + builder = EnvBuilder(system_site_packages=options.system_site, + clear=options.clear, symlinks=options.symlinks, + upgrade=options.upgrade) + for d in options.dirs: + builder.create(d) + +if __name__ == '__main__': + rc = 1 + try: + main() + rc = 0 + except Exception as e: + print('Error: %s' % e, file=sys.stderr) + sys.exit(rc) |