venv
— Creation of virtual environments¶
Added in version 3.3.
소스 코드: Lib/venv/
The venv
module supports creating lightweight “virtual environments”,
each with their own independent set of Python packages installed in
their site
directories.
A virtual environment is created on top of an existing
Python installation, known as the virtual environment’s “base” Python, and may
optionally be isolated from the packages in the base environment,
so only those explicitly installed in the virtual environment are available.
When used from within a virtual environment, common installation tools such as pip will install Python packages into a virtual environment without needing to be told to do so explicitly.
A virtual environment is (amongst other things):
Used to contain a specific Python interpreter and software libraries and binaries which are needed to support a project (library or application). These are by default isolated from software in other virtual environments and Python interpreters and libraries installed in the operating system.
Contained in a directory, conventionally named
.venv
orvenv
in the project directory, or under a container directory for lots of virtual environments, such as~/.virtualenvs
.Not checked into source control systems such as Git.
Considered as disposable – it should be simple to delete and recreate it from scratch. You don’t place any project code in the environment.
Not considered as movable or copyable – you just recreate the same environment in the target location.
See PEP 405 for more background on Python virtual environments.
Availability: not Emscripten, not WASI.
This module does not work or is not available on WebAssembly platforms
wasm32-emscripten
and wasm32-wasi
. See
WebAssembly platforms for more information.
가상 환경 만들기¶
Virtual environments are created by executing the venv
module:
python -m venv /path/to/new/virtual/environment
This creates the target directory (including parent directories as needed)
and places a pyvenv.cfg
file in it with a home
key
pointing to the Python installation from which the command was run.
It also creates a bin
(or Scripts
on Windows) subdirectory
containing a copy or symlink of the Python executable
(as appropriate for the platform or arguments used at environment creation time).
It also creates a lib/pythonX.Y/site-packages
subdirectory
(on Windows, this is Libsite-packages
).
If an existing directory is specified, it will be re-used.
버전 3.5에서 변경: 이제 가상 환경을 만들 때 venv
를 사용하는 것이 좋습니다.
Deprecated since version 3.6, removed in version 3.8: pyvenv was the recommended tool for creating virtual environments
for Python 3.3 and 3.4, and replaced in 3.5 by executing venv
directly.
On Windows, invoke the venv
command as follows:
PS> python -m venv C:\path\to\new\virtual\environment
명령에 -h
를 사용하면 사용 가능한 옵션이 표시됩니다:
usage: venv [-h] [--system-site-packages] [--symlinks | --copies] [--clear]
[--upgrade] [--without-pip] [--prompt PROMPT] [--upgrade-deps]
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.
options:
-h, --help show this help message and exit
--system-site-packages
Give the virtual environment access to the system
site-packages dir.
--symlinks Try to use symlinks rather than copies, when
symlinks are not the default for the platform.
--copies Try to use copies rather than symlinks, even when
symlinks are the default for the platform.
--clear Delete the contents of the environment directory
if it already exists, before environment creation.
--upgrade Upgrade the environment directory to use this
version of Python, assuming Python has been
upgraded in-place.
--without-pip Skips installing or upgrading pip in the virtual
environment (pip is bootstrapped by default)
--prompt PROMPT Provides an alternative prompt prefix for this
environment.
--upgrade-deps Upgrade core dependencies (pip) to the latest
version in PyPI
Once an environment has been created, you may wish to activate it, e.g. by
sourcing an activate script in its bin directory.
버전 3.4에서 변경: Installs pip by default, added the --without-pip
and --copies
options.
버전 3.4에서 변경: 이전 버전에서는, --clear
나 --upgrade
옵션이 제공되지 않았을 때, 대상 디렉터리가 이미 존재하면 에러가 발생했습니다.
버전 3.9에서 변경: Add --upgrade-deps
option to upgrade pip + setuptools to the latest on PyPI.
버전 3.12에서 변경: setuptools
is no longer a core venv dependency.
참고
심볼릭 링크가 윈도우에서 지원되지만, 추천하지는 않습니다. 특히 파일 탐색기에서 python.exe
를 더블 클릭하면 심볼릭 링크를 열심히 따라가고(resolve) 가상 환경은 무시됩니다.
참고
마이크로소프트 윈도우에서는 사용자에 대한 실행 정책을 설정하여 Activate.ps1
스크립트를 활성화해야 할 수도 있습니다. 다음 PowerShell 명령을 실행하여 이를 수행할 수 있습니다:
PS C:\> Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
자세한 정보는 About Execution Policies를 참조하십시오.
The created pyvenv.cfg
file also includes the
include-system-site-packages
key, set to true
if venv
is
run with the --system-site-packages
option, false
otherwise.
--without-pip
옵션을 주지 않는 한, 가상 환경으로 pip
을 부트스트랩 하기 위해 ensurepip
가 호출됩니다.
venv
에 여러 경로를 지정할 수 있습니다. 이때 지정된 옵션에 따라 제공된 각 경로에서 같은 가상 환경이 만들어집니다.
How venvs work¶
When a Python interpreter is running from a virtual environment,
sys.prefix
and sys.exec_prefix
point to the directories of the virtual environment,
whereas sys.base_prefix
and sys.base_exec_prefix
point to those of the base Python used to create the environment.
It is sufficient to check
sys.prefix != sys.base_prefix
to determine if the current interpreter is
running from a virtual environment.
A virtual environment may be “activated” using a script in its binary directory
(bin
on POSIX; Scripts
on Windows).
This will prepend that directory to your PATH
, so that running
python will invoke the environment’s Python interpreter
and you can run installed scripts without having to use their full path.
The invocation of the activation script is platform-specific
(<venv>
must be replaced by the path to the directory
containing the virtual environment):
플랫폼 |
셸 |
가상 환경을 활성화하는 명령 |
---|---|---|
POSIX |
bash/zsh |
|
fish |
|
|
csh/tcsh |
|
|
PowerShell |
|
|
윈도우 |
cmd.exe |
|
PowerShell |
|
Added in version 3.4: fish and csh activation scripts.
Added in version 3.8: PowerShell Core 지원을 위해 POSIX에 설치된 PowerShell 활성화 스크립트.
You don’t specifically need to activate a virtual environment, as you can just specify the full path to that environment’s Python interpreter when invoking Python. Furthermore, all scripts installed in the environment should be runnable without activating it.
In order to achieve this, scripts installed into virtual environments have
a “shebang” line which points to the environment’s Python interpreter,
#!/<path-to-venv>/bin/python
.
This means that the script will run with that interpreter regardless of the
value of PATH
. On Windows, “shebang” line processing is supported if
you have the 윈도우 용 파이썬 런처 installed. Thus, double-clicking an installed
script in a Windows Explorer window should run it with the correct interpreter
without the environment needing to be activated or on the PATH
.
When a virtual environment has been activated, the VIRTUAL_ENV
environment variable is set to the path of the environment.
Since explicitly activating a virtual environment is not required to use it,
VIRTUAL_ENV
cannot be relied upon to determine
whether a virtual environment is being used.
경고
Because scripts installed in environments should not expect the
environment to be activated, their shebang lines contain the absolute paths
to their environment’s interpreters. Because of this, environments are
inherently non-portable, in the general case. You should always have a
simple means of recreating an environment (for example, if you have a
requirements file requirements.txt
, you can invoke pip install -r
requirements.txt
using the environment’s pip
to install all of the
packages needed by the environment). If for any reason you need to move the
environment to a new location, you should recreate it at the desired
location and delete the one at the old location. If you move an environment
because you moved a parent directory of it, you should recreate the
environment in its new location. Otherwise, software installed into the
environment may not work as expected.
You can deactivate a virtual environment by typing deactivate
in your shell.
The exact mechanism is platform-specific and is an internal implementation
detail (typically, a script or shell function will be used).
API¶
위에서 설명한 고수준 메서드는 제삼자 가상 환경 작성자가 필요에 따라 환경을 사용자 정의할 수 있는 메커니즘을 제공하는 간단한 API를 사용합니다: EnvBuilder
클래스.
- class venv.EnvBuilder(system_site_packages=False, clear=False, symlinks=False, upgrade=False, with_pip=False, prompt=None, upgrade_deps=False)¶
EnvBuilder
클래스는 인스턴스를 만들 때 다음 키워드 인자를 받아들입니다:system_site_packages – a boolean value indicating that the system Python site-packages should be available to the environment (defaults to
False
).clear – a boolean value which, if true, will delete the contents of any existing target directory, before creating the environment.
symlinks – a boolean value indicating whether to attempt to symlink the Python binary rather than copying.
upgrade – a boolean value which, if true, will upgrade an existing environment with the running Python - for use when that Python has been upgraded in-place (defaults to
False
).with_pip – a boolean value which, if true, ensures pip is installed in the virtual environment. This uses
ensurepip
with the--default-pip
option.prompt – a string to be used after virtual environment is activated (defaults to
None
which means directory name of the environment would be used). If the special string"."
is provided, the basename of the current directory is used as the prompt.upgrade_deps – Update the base venv modules to the latest on PyPI
버전 3.4에서 변경:
with_pip
매개 변수 추가버전 3.6에서 변경:
prompt
매개 변수 추가버전 3.9에서 변경:
upgrade_deps
매개 변수 추가EnvBuilder
may be used as a base class.- create(env_dir)¶
가상 환경을 담을 대상 디렉터리(절대 또는 현재 디렉터리에 대한 상대)를 지정해서 가상 환경을 만듭니다.
create
메서드는 지정된 디렉터리에 환경을 만들거나 적절한 예외를 발생시킵니다.EnvBuilder
클래스의create
메서드는 서브 클래스가 사용자 정의할 수 있는 훅을 보여줍니다:def create(self, env_dir): """ Create a virtualized Python environment in a directory. env_dir is 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) self.setup_scripts(context) self.post_setup(context)
메서드
ensure_directories()
,create_configuration()
,setup_python()
,setup_scripts()
및post_setup()
각각을 재정의할 수 있습니다.
- ensure_directories(env_dir)¶
Creates the environment directory and all necessary subdirectories that don’t already exist, and returns a context object. This context object is just a holder for attributes (such as paths) for use by the other methods. If the
EnvBuilder
is created with the argclear=True
, contents of the environment directory will be cleared and then all necessary subdirectories will be recreated.The returned context object is a
types.SimpleNamespace
with the following attributes:env_dir
- The location of the virtual environment. Used for__VENV_DIR__
in activation scripts (seeinstall_scripts()
).env_name
- The name of the virtual environment. Used for__VENV_NAME__
in activation scripts (seeinstall_scripts()
).prompt
- The prompt to be used by the activation scripts. Used for__VENV_PROMPT__
in activation scripts (seeinstall_scripts()
).executable
- The underlying Python executable used by the virtual environment. This takes into account the case where a virtual environment is created from another virtual environment.inc_path
- The include path for the virtual environment.lib_path
- The purelib path for the virtual environment.bin_path
- The script path for the virtual environment.bin_name
- The name of the script path relative to the virtual environment location. Used for__VENV_BIN_NAME__
in activation scripts (seeinstall_scripts()
).env_exe
- The name of the Python interpreter in the virtual environment. Used for__VENV_PYTHON__
in activation scripts (seeinstall_scripts()
).env_exec_cmd
- The name of the Python interpreter, taking into account filesystem redirections. This can be used to run Python in the virtual environment.
버전 3.11에서 변경: The venv sysconfig installation scheme is used to construct the paths of the created directories.
버전 3.12에서 변경: The attribute
lib_path
was added to the context, and the context object was documented.
- create_configuration(context)¶
환경에
pyvenv.cfg
구성 파일을 만듭니다.
- setup_python(context)¶
환경에 파이썬 실행 파일의 복사본이나 심볼릭 링크를 만듭니다. POSIX 시스템에서, 특정 실행 파일
python3.x
가 사용되면, 해당 이름의 파일이 이미 존재하지 않는 한python
과python3
심볼릭 링크가 해당 실행 파일을 가리키도록 만들어집니다.
- setup_scripts(context)¶
플랫폼에 적합한 활성화 스크립트를 가상 환경에 설치합니다.
- upgrade_dependencies(context)¶
Upgrades the core venv dependency packages (currently pip) in the environment. This is done by shelling out to the
pip
executable in the environment.Added in version 3.9.
버전 3.12에서 변경: setuptools is no longer a core venv dependency.
- post_setup(context)¶
제삼자 구현에서 재정의하여 가상 환경에 패키지를 사전 설치하거나 다른 생성 후 단계를 수행할 수 있는 메서드입니다.
- install_scripts(context, path)¶
This method can be called from
setup_scripts()
orpost_setup()
in subclasses to assist in installing custom scripts into the virtual environment.path is the path to a directory that should contain subdirectories
common
,posix
,nt
; each containing scripts destined for thebin
directory in the environment. The contents ofcommon
and the directory corresponding toos.name
are copied after some text replacement of placeholders:__VENV_DIR__
은 환경 디렉터리의 절대 경로로 치환됩니다.__VENV_NAME__
은 환경 이름(환경 디렉터리의 최종 경로 세그먼트)으로 치환됩니다.__VENV_PROMPT__
는 프롬프트(괄호로 묶인 환경 이름과 그 뒤의 스페이스)로 치환됩니다__VENV_BIN_NAME__
은 bin 디렉터리의 이름(bin
이나Scripts
)으로 치환됩니다.__VENV_PYTHON__
은 환경의 실행 파일의 절대 경로로 치환됩니다.
디렉터리는 존재하는 것이 허용됩니다 (기존 환경이 업그레이드될 때).
버전 3.7.2에서 변경: 윈도우는 이제 실제 바이너리를 복사하는 대신
python[w].exe
를 위한 리디렉터 스크립트를 사용합니다. 3.7.2 에서만, 소스 트리의 빌드에서 실행하지 않는 한setup_python()
아무 작업도 수행하지 않습니다.버전 3.7.3에서 변경: 윈도우는
setup_scripts()
대신setup_python()
의 일부로 리디렉터 스크립트를 복사합니다. 이것은 3.7.2는 해당하지 않습니다. 심볼릭 링크를 사용하면, 원래 실행 파일이 링크됩니다.
모듈 수준의 편리 함수도 있습니다:
- venv.create(env_dir, system_site_packages=False, clear=False, symlinks=False, with_pip=False, prompt=None, upgrade_deps=False)¶
주어진 키워드 인자로
EnvBuilder
를 만들고, env_dir 인자로create()
메서드를 호출합니다.Added in version 3.3.
버전 3.4에서 변경: Added the with_pip parameter
버전 3.6에서 변경: Added the prompt parameter
버전 3.9에서 변경: Added the upgrade_deps parameter
EnvBuilder
확장 예제¶
다음 스크립트는 생성된 가상 환경에 setuptools 와 pip을 설치하는 서브 클래스를 구현하여 EnvBuilder
를 확장하는 방법을 보여줍니다:
import os
import os.path
from subprocess import Popen, PIPE
import sys
from threading import Thread
from urllib.parse import urlparse
from urllib.request import urlretrieve
import venv
class ExtendedEnvBuilder(venv.EnvBuilder):
"""
This builder installs setuptools and pip so that you can pip or
easy_install other packages into the created virtual environment.
:param nodist: If true, setuptools and pip are not installed into the
created virtual environment.
:param nopip: If true, pip is not installed into the created
virtual environment.
:param progress: If setuptools or pip are 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 the app.
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.nopip = kwargs.pop('nopip', False)
self.progress = kwargs.pop('progress', None)
self.verbose = kwargs.pop('verbose', False)
super().__init__(*args, **kwargs)
def post_setup(self, context):
"""
Set up any packages which need to be pre-installed into the
virtual environment being created.
:param context: The information for the virtual environment
creation request being processed.
"""
os.environ['VIRTUAL_ENV'] = context.env_dir
if not self.nodist:
self.install_setuptools(context)
# Can't install pip without setuptools
if not self.nopip and not self.nodist:
self.install_pip(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:
if not self.verbose:
sys.stderr.write('.')
else:
sys.stderr.write(s.decode('utf-8'))
sys.stderr.flush()
stream.close()
def install_script(self, context, name, url):
_, _, path, _, _, _ = urlparse(url)
fn = os.path.split(path)[-1]
binpath = context.bin_path
distpath = os.path.join(binpath, fn)
# Download script into the virtual environment's binaries folder
urlretrieve(url, distpath)
progress = self.progress
if self.verbose:
term = '\n'
else:
term = ''
if progress is not None:
progress('Installing %s ...%s' % (name, term), 'main')
else:
sys.stderr.write('Installing %s ...%s' % (name, term))
sys.stderr.flush()
# Install in the virtual environment
args = [context.env_exe, fn]
p = Popen(args, stdout=PIPE, stderr=PIPE, cwd=binpath)
t1 = Thread(target=self.reader, args=(p.stdout, 'stdout'))
t1.start()
t2 = 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 install_setuptools(self, context):
"""
Install setuptools in the virtual environment.
:param context: The information for the virtual environment
creation request being processed.
"""
url = "https://bootstrap.pypa.io/ez_setup.py"
self.install_script(context, 'setuptools', url)
# clear up the setuptools archive which gets downloaded
pred = lambda o: o.startswith('setuptools-') and o.endswith('.tar.gz')
files = filter(pred, os.listdir(context.bin_path))
for f in files:
f = os.path.join(context.bin_path, f)
os.unlink(f)
def install_pip(self, context):
"""
Install pip in the virtual environment.
:param context: The information for the virtual environment
creation request being processed.
"""
url = 'https://bootstrap.pypa.io/get-pip.py'
self.install_script(context, 'pip', url)
def main(args=None):
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 in which to create the '
'virtual environment.')
parser.add_argument('--no-setuptools', default=False,
action='store_true', dest='nodist',
help="Don't install setuptools or pip in the "
"virtual environment.")
parser.add_argument('--no-pip', default=False,
action='store_true', dest='nopip',
help="Don't install pip 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':
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 contents of the '
'virtual environment '
'directory if it already '
'exists, before virtual '
'environment creation.')
parser.add_argument('--upgrade', default=False, action='store_true',
dest='upgrade', help='Upgrade the virtual '
'environment directory to '
'use this version of '
'Python, assuming Python '
'has been upgraded '
'in-place.')
parser.add_argument('--verbose', default=False, action='store_true',
dest='verbose', help='Display the output '
'from the scripts which '
'install setuptools and pip.')
options = parser.parse_args(args)
if options.upgrade and options.clear:
raise ValueError('you cannot supply --upgrade and --clear together.')
builder = ExtendedEnvBuilder(system_site_packages=options.system_site,
clear=options.clear,
symlinks=options.symlinks,
upgrade=options.upgrade,
nodist=options.nodist,
nopip=options.nopip,
verbose=options.verbose)
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)
이 스크립트는 온라인에서 내려받을 수도 있습니다.