python-mvenv/path/to/new/virtual/environment

PS>python-mvenvC:\path\to\new\virtual\environment

usage: venv [-h] [--system-site-packages] [--symlinks | --copies] [--clear]            [--upgrade] [--without-pip] [--prompt PROMPT] [--upgrade-deps]            [--without-scm-ignore-files]            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  --without-scm-ignore-files                        Skips adding SCM ignore files to the environment                        directory (Git is supported by default).Once an environment has been created, you may wish to activate it, e.g. bysourcing an activate script in its bin directory.

importosimportos.pathfromsubprocessimportPopen,PIPEimportsysfromthreadingimportThreadfromurllib.parseimporturlparsefromurllib.requestimporturlretrieveimportvenvclassExtendedEnvBuilder(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)defpost_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_dirifnotself.nodist:self.install_setuptools(context)# Can't install pip without setuptoolsifnotself.nopipandnotself.nodist:self.install_pip(context)defreader(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.progresswhileTrue:s=stream.readline()ifnots:breakifprogressisnotNone:progress(s,context)else:ifnotself.verbose:sys.stderr.write('.')else:sys.stderr.write(s.decode('utf-8'))sys.stderr.flush()stream.close()definstall_script(self,context,name,url):_,_,path,_,_,_=urlparse(url)fn=os.path.split(path)[-1]binpath=context.bin_pathdistpath=os.path.join(binpath,fn)# Download script into the virtual environment's binaries folderurlretrieve(url,distpath)progress=self.progressifself.verbose:term='\n'else:term=''ifprogressisnotNone:progress('Installing%s ...%s'%(name,term),'main')else:sys.stderr.write('Installing%s ...%s'%(name,term))sys.stderr.flush()# Install in the virtual environmentargs=[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()ifprogressisnotNone:progress('done.','main')else:sys.stderr.write('done.\n')# Clean up - no longer neededos.unlink(distpath)definstall_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 downloadedpred=lambdao:o.startswith('setuptools-')ando.endswith('.tar.gz')files=filter(pred,os.listdir(context.bin_path))forfinfiles:f=os.path.join(context.bin_path,f)os.unlink(f)definstall_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)defmain(args=None):importargparseparser=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.')ifos.name=='nt':use_symlinks=Falseelse:use_symlinks=Trueparser.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)ifoptions.upgradeandoptions.clear:raiseValueError('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)fordinoptions.dirs:builder.create(d)if__name__=='__main__':rc=1try:main()rc=0exceptExceptionase:print('Error:%s'%e,file=sys.stderr)sys.exit(rc)