module pycode.venv_helper

Short summary

module pyquickhelper.pycode.venv_helper

Helpers for virtualenv

source on GitHub

Classes

class	truncated documentation
NotImplementedErrorFromVirtualEnvironment	Defines an exception when a function does not work in a virtual environment.
VirtualEnvError	Exception raised by the function implemented in this file.

Functions

function	truncated documentation
build_venv_cmd	Builds the command line for virtual env.
check_readme_syntax	Checks the syntax of the file readme.rst which describes a python project.
create_virtual_env	Creates a virtual environment.
is_virtual_environment	Tells if the script is run from a virtual environment.
run_base_script	Runs a script with the original intepreter even if this function is run from a virtual environment.
run_venv_script	Runs a script on a vritual environment (the script should be simple).
venv_install	Installs a package or a list of packages in a virtual environment.

Documentation

Helpers for virtualenv

source on GitHub

exception pyquickhelper.pycode.venv_helper.NotImplementedErrorFromVirtualEnvironment

Bases: NotImplementedError

Defines an exception when a function does not work in a virtual environment.

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exception pyquickhelper.pycode.venv_helper.VirtualEnvError

Bases: Exception

Exception raised by the function implemented in this file.

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pyquickhelper.pycode.venv_helper.build_venv_cmd(params, posparams)

Builds the command line for virtual env.

Parameters

• params – dictionary of parameters

• posparams – positional arguments

Returns

string

source on GitHub

pyquickhelper.pycode.venv_helper.check_readme_syntax(readme, folder, version='0.8', fLOG=None)

Checks the syntax of the file readme.rst which describes a python project.

Parameters

• readme – file to check

• folder – location for the virtual environment

• version – version of docutils

• fLOG – logging function

Returns

output or SyntaxError exception

pipy server is based on docutils ==0.8. The most simple way to check its syntax is to create a virtual environment, to install docutils==0.8 and to compile the file. This is what this function does.

Unfortunately, this functionality does not work yet from a virtual environment.

source on GitHub

pyquickhelper.pycode.venv_helper.create_virtual_env(where, symlinks=False, system_site_packages=False, clear=True, packages=None, fLOG=None, temp_folder=None, platform=None)

Creates a virtual environment.

Parameters

• where – location of this virtual environment

• symlinks – attempt to symlink rather than copy

• system_site_packages – Give the virtual environment access to the system site-packages dir

• clear – Delete the environment directory if it already exists. If not specified and the directory exists, an error is raised.

• packages – list of packages to install (it will install module pymyinstall).

• fLOG – logging function

• temp_folder – temporary folder (to download module if needed), by default <where>/download

• platform – platform to use

Returns

stand output

How to create a virtual environment?

The following example creates a virtual environment. Packages can be added by specifying the parameter package.

from pyquickhelper.pycode import create_virtual_env
fold = "my_env"
if not os.path.exists(fold):
    os.mkdir(fold)
create_virtual_env(fold)

The function does not work from a virtual environment.

source on GitHub

pyquickhelper.pycode.venv_helper.is_virtual_environment()

Tells if the script is run from a virtual environment.

Returns

boolean

source on GitHub

pyquickhelper.pycode.venv_helper.run_base_script(script, fLOG=None, file=False, is_cmd=False, skip_err_if=None, argv=None, platform=None, **kwargs)

Runs a script with the original intepreter even if this function is run from a virtual environment.

Parameters

• script – script as a string (not a file)

• fLOG – logging function

• file – is script a file or a string to execute

• is_cmd – if True, script is a command line to run (as a list) for python executable

• skip_err_if – do not pay attention to standard error if this string was found in standard output

• argv – list of arguments to add on the command line

• platform – platform (sys.platform by default)

• kwargs – others arguments for function run_cmd.

Returns

output

The function does not work from a virtual environment. The function does not raise an exception if the standard error contains something like:

----------------------------------------------------------------------
Ran 1 test in 0.281s

OK

source on GitHub

pyquickhelper.pycode.venv_helper.run_venv_script(venv, script, fLOG=None, file=False, is_cmd=False, skip_err_if=None, platform=None, **kwargs)

Runs a script on a vritual environment (the script should be simple).

Parameters

• venv – virtual environment

• script – script as a string (not a file)

• fLOG – logging function

• file – is script a file or a string to execute

• is_cmd – if True, script is a command line to run (as a list) for python executable

• skip_err_if – do not pay attention to standard error if this string was found in standard output

• platform – platform (sys.platform by default)

• kwargs – others arguments for function run_cmd.

Returns

output

The function does not work from a virtual environment.

source on GitHub

pyquickhelper.pycode.venv_helper.venv_install(venv, packages, fLOG=None, temp_folder=None, platform=None)

Installs a package or a list of packages in a virtual environment.

Parameters

• venv – location of the virtual environment

• packages – a package (str) or a list of packages(list[str])

• fLOG – logging function

• temp_folder – temporary folder (to download module if needed), by default <where>/download

• platform – platform (sys.platform by default)

Returns

standard output

The function does not work from a virtual environment.

source on GitHub