cpython/Lib/venv/__init__.py

511 lines
20 KiB
Python

"""
Virtual environment (venv) package for Python. Based on PEP 405.
Copyright (C) 20011-2012 Vinay Sajip. All Rights Reserved.
usage: python -m venv [-h] [--no-distribute] [--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
--no-distribute Don't install Distribute in the virtual environment.*
--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.
*Note: Distribute support will be available during the alpha phase to
facilitate testing third-party packages with venvs created using this package.
This support will be removed after the alpha phase.
"""
import base64
import io
import logging
import os
import os.path
import shutil
import sys
try:
import threading
except ImportError:
threading = None
import zipfile
logger = logging.getLogger(__name__)
class Context:
"""
Holds information about a current venv creation/upgrade request.
"""
pass
class EnvBuilder:
"""
This class exists to allow virtual environment creation to be
customised. 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
available to the created environment.
By default, the creation process uses symlinks wherever possible.
: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.
"""
if (self.symlinks and
sys.platform == 'darwin' and
'Library/Framework' in sys.base_prefix):
# Symlinking the stub executable in an OSX framework build will
# result in a broken virtual environment.
raise ValueError(
"Symlinking is not supported on OSX framework Python.")
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 = Context()
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 '__PYTHONV_LAUNCHER__' in env:
executable = os.environ['__PYTHONV_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)
path = os.path.join(binpath, 'python')
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'
data = data.decode('utf-8')
data = self.replace_variables(data, context)
with open(dstfile, mode) as f:
f.write(data)
os.chmod(dstfile, 0o755)
# This class will not be included in Python core; it's here for now to
# facilitate experimentation and testing, and as proof-of-concept of what could
# be done by external extension tools.
class DistributeEnvBuilder(EnvBuilder):
"""
By default, this builder installs Distribute so that you can pip or
easy_install other packages into the created environment.
:param nodist: If True, Distribute is not installed into the created
environment.
:param progress: If Distribute is installed, the progress of the
installation can be monitored by passing a progress
callable. If specified, it is called with two
arguments: a string indicating some progress, and a
context indicating where the string is coming from.
The context argument can have one of three values:
'main', indicating that it is called from virtualize()
itself, and 'stdout' and 'stderr', which are obtained
by reading lines from the output streams of a subprocess
which is used to install Distribute.
If a callable is not specified, default progress
information is output to sys.stderr.
"""
def __init__(self, *args, **kwargs):
self.nodist = kwargs.pop("nodist", False)
self.progress = kwargs.pop("progress", None)
super().__init__(*args, **kwargs)
def post_setup(self, context):
"""
Set up any packages which need to be pre-installed into the
environment being created.
:param context: The information for the environment creation request
being processed.
"""
if not self.nodist:
if threading:
self.install_distribute(context)
def reader(self, stream, context):
"""
Read lines from a subprocess' output stream and either pass to a progress
callable (if specified) or write progress information to sys.stderr.
"""
progress = self.progress
while True:
s = stream.readline()
if not s:
break
if progress is not None:
progress(s, context)
else:
sys.stderr.write('.')
#sys.stderr.write(s.decode('utf-8'))
sys.stderr.flush()
stream.close()
def install_distribute(self, context):
"""
Install Distribute in the environment.
:param context: The information for the environment creation request
being processed.
"""
from subprocess import Popen, PIPE
from urllib.request import urlretrieve
url = 'http://python-distribute.org/distribute_setup.py'
binpath = context.bin_path
distpath = os.path.join(binpath, 'distribute_setup.py')
# Download Distribute in the env
urlretrieve(url, distpath)
progress = self.progress
if progress is not None:
progress('Installing distribute', 'main')
else:
sys.stderr.write('Installing distribute ')
sys.stderr.flush()
# Install Distribute in the env
args = [context.env_exe, 'distribute_setup.py']
p = Popen(args, stdout=PIPE, stderr=PIPE, cwd=binpath)
t1 = threading.Thread(target=self.reader, args=(p.stdout, 'stdout'))
t1.start()
t2 = threading.Thread(target=self.reader, args=(p.stderr, 'stderr'))
t2.start()
p.wait()
t1.join()
t2.join()
if progress is not None:
progress('done.', 'main')
else:
sys.stderr.write('done.\n')
# Clean up - no longer needed
os.unlink(distpath)
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 available to
the created environment.
: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.
"""
# XXX This should be changed to EnvBuilder.
builder = DistributeEnvBuilder(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 (pythonv variant)')
else:
import argparse
parser = argparse.ArgumentParser(prog=__name__,
description='Creates virtual Python '
'environments in one or '
'more target '
'directories.')
parser.add_argument('dirs', metavar='ENV_DIR', nargs='+',
help='A directory to create the environment in.')
# XXX This option will be removed.
parser.add_argument('--no-distribute', default=False,
action='store_true', dest='nodist',
help="Don't install Distribute in the virtual "
"environment.")
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' or (sys.platform == 'darwin' and
'Library/Framework' in sys.base_prefix):
use_symlinks = False
else:
use_symlinks = True
parser.add_argument('--symlinks', default=use_symlinks,
action='store_true', dest='symlinks',
help="Attempt to symlink rather than copy.")
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.')
# XXX This will be changed to EnvBuilder
builder = DistributeEnvBuilder(system_site_packages=options.system_site,
clear=options.clear,
symlinks=options.symlinks,
upgrade=options.upgrade,
nodist=options.nodist)
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)