Source code for xontrib.voxapi

"""
API for Vox, the Python virtual environment manager for xonsh.

Vox defines several events related to the life cycle of virtual environments:

* ``vox_on_create(env: str) -> None``
* ``vox_on_activate(env: str) -> None``
* ``vox_on_deactivate(env: str) -> None``
* ``vox_on_delete(env: str) -> None``
"""
import os
import sys
import shutil
import logging
import builtins
import collections.abc
import subprocess as sp


from xonsh.platform import ON_POSIX, ON_WINDOWS
from xonsh.fs import PathLike, fspath

# This is because builtins aren't globally created during testing.
# FIXME: Is there a better way?
from xonsh.events import events


events.doc(
    "vox_on_create",
    """
vox_on_create(env: str) -> None

Fired after an environment is created.
""",
)

events.doc(
    "vox_on_activate",
    """
vox_on_activate(env: str) -> None

Fired after an environment is activated.
""",
)

events.doc(
    "vox_on_deactivate",
    """
vox_on_deactivate(env: str) -> None

Fired after an environment is deactivated.
""",
)

events.doc(
    "vox_on_delete",
    """
vox_on_delete(env: str) -> None

Fired after an environment is deleted (through vox).
""",
)


VirtualEnvironment = collections.namedtuple(
    "VirtualEnvironment", ["env", "bin", "lib", "inc"]
)


def _subdir_names():
    """
    Gets the names of the special dirs in a venv.

    This is not necessarily exhaustive of all the directories that could be in a venv, and there
    may additional logic to get to useful places.
    """
    if ON_WINDOWS:
        return "Scripts", "Lib", "Include"
    elif ON_POSIX:
        return "bin", "lib", "include"
    else:
        raise OSError("This OS is not supported.")


def _mkvenv(env_dir):
    """
    Constructs a VirtualEnvironment based on the given base path.

    This only cares about the platform. No filesystem calls are made.
    """
    env_dir = os.path.normpath(env_dir)
    if ON_WINDOWS:
        binname = os.path.join(env_dir, "Scripts")
        incpath = os.path.join(env_dir, "Include")
        libpath = os.path.join(env_dir, "Lib", "site-packages")
    elif ON_POSIX:
        binname = os.path.join(env_dir, "bin")
        incpath = os.path.join(env_dir, "include")
        libpath = os.path.join(
            env_dir, "lib", "python%d.%d" % sys.version_info[:2], "site-packages"
        )
    else:
        raise OSError("This OS is not supported.")

    return VirtualEnvironment(env_dir, binname, libpath, incpath)


[docs]class EnvironmentInUse(Exception): """The given environment is currently activated, and the operation cannot be performed."""
[docs]class NoEnvironmentActive(Exception): """No environment is currently activated, and the operation cannot be performed."""
[docs]class Vox(collections.abc.Mapping): """API access to Vox and virtual environments, in a dict-like format. Makes use of the VirtualEnvironment namedtuple: 1. ``env``: The full path to the environment 2. ``bin``: The full path to the bin/Scripts directory of the environment """ def __init__(self): if not builtins.__xonsh__.env.get("VIRTUALENV_HOME"): home_path = os.path.expanduser("~") self.venvdir = os.path.join(home_path, ".virtualenvs") builtins.__xonsh__.env["VIRTUALENV_HOME"] = self.venvdir else: self.venvdir = builtins.__xonsh__.env["VIRTUALENV_HOME"]
[docs] def create( self, name, interpreter=None, system_site_packages=False, symlinks=False, with_pip=True, ): """Create a virtual environment in $VIRTUALENV_HOME with python3's ``venv``. Parameters ---------- name : str Virtual environment name interpreter: str Python interpreter used to create the virtual environment. system_site_packages : bool If True, the system (global) site-packages dir is available to created environments. symlinks : bool If True, attempt to symlink rather than copy files into virtual environment. with_pip : bool If True, ensure pip is installed in the virtual environment. (Default is True) """ interpreter = ( _get_vox_default_interpreter() if interpreter is None else interpreter ) # NOTE: clear=True is the same as delete then create. # NOTE: upgrade=True is its own method if isinstance(name, PathLike): env_path = fspath(name) else: env_path = os.path.join(self.venvdir, name) if not self._check_reserved(env_path): raise ValueError( "venv can't contain reserved names ({})".format( ", ".join(_subdir_names()) ) ) self._create(env_path, interpreter, symlinks=symlinks, with_pip=with_pip) events.vox_on_create.fire(name=name)
[docs] def upgrade(self, name, symlinks=False, with_pip=True, interpreter=None): """Create a virtual environment in $VIRTUALENV_HOME with python3's ``venv``. WARNING: If a virtual environment was created with symlinks or without PIP, you must specify these options again on upgrade. Parameters ---------- name : str Virtual environment name interpreter: str The Python interpreter used to create the virtualenv symlinks : bool If True, attempt to symlink rather than copy files into virtual environment. with_pip : bool If True, ensure pip is installed in the virtual environment. """ interpreter = ( _get_vox_default_interpreter() if interpreter is None else interpreter ) # venv doesn't reload this, so we have to do it ourselves. # Is there a bug for this in Python? There should be. env_path, bin_path = self[name] cfgfile = os.path.join(env_path, "pyvenv.cfg") cfgops = {} with open(cfgfile) as cfgfile: for l in cfgfile: l = l.strip() if "=" not in l: continue k, v = l.split("=", 1) cfgops[k.strip()] = v.strip() flags = { "system_site_packages": cfgops["include-system-site-packages"] == "true", "symlinks": symlinks, "with_pip": with_pip, } # END things we shouldn't be doing. # Ok, do what we came here to do. self._create(env_path, interpreter, upgrade=True, **flags)
@staticmethod def _create( env_path, interpreter, system_site_packages=False, symlinks=False, with_pip=True, upgrade=False, ): version_output = sp.check_output( [interpreter, "--version"], stderr=sp.STDOUT, universal_newlines=True ) interpreter_major_version = int(version_output.split()[-1].split(".")[0]) module = "venv" if interpreter_major_version >= 3 else "virtualenv" system_site_packages = "--system-site-packages" if system_site_packages else "" symlinks = "--symlinks" if symlinks and interpreter_major_version >= 3 else "" with_pip = "" if with_pip else "--without-pip" upgrade = "--upgrade" if upgrade else "" cmd = [ interpreter, "-m", module, env_path, system_site_packages, symlinks, with_pip, upgrade, ] cmd = [arg for arg in cmd if arg] # remove empty args logging.debug(cmd) return_code = sp.call(cmd) if return_code != 0: raise SystemExit(return_code) @staticmethod def _check_reserved(name): return ( os.path.basename(name) not in _subdir_names() ) # FIXME: Check the middle components, too def __getitem__(self, name): """Get information about a virtual environment. Parameters ---------- name : str or Ellipsis Virtual environment name or absolute path. If ... is given, return the current one (throws a KeyError if there isn't one). """ if name is ...: env_paths = [builtins.__xonsh__.env["VIRTUAL_ENV"]] elif isinstance(name, PathLike): env_paths = [fspath(name)] else: if not self._check_reserved(name): # Don't allow a venv that could be a venv special dir raise KeyError() env_paths = [] if os.path.isdir(name): env_paths += [name] env_paths += [os.path.join(self.venvdir, name)] for ep in env_paths: ve = _mkvenv(ep) # Actually check if this is an actual venv or just a organizational directory # eg, if 'spam/eggs' is a venv, reject 'spam' if not os.path.exists(ve.bin): continue return ve else: raise KeyError() def __contains__(self, name): # For some reason, MutableMapping seems to do this against iter, which is just silly. try: self[name] except KeyError: return False else: return True def __iter__(self): """List available virtual environments found in $VIRTUALENV_HOME. """ bin_, lib, inc = _subdir_names() for dirpath, dirnames, filenames in os.walk(self.venvdir): python_exec = os.path.join(dirpath, bin_, "python") if ON_WINDOWS: python_exec += ".exe" if os.access(python_exec, os.X_OK): yield dirpath[len(self.venvdir) + 1 :] # +1 is to remove the separator dirnames.clear() def __len__(self): """Counts known virtual environments, using the same rules as iter(). """ l = 0 for _ in self: l += 1 return l
[docs] def active(self): """Get the name of the active virtual environment. You can use this as a key to get further information. Returns None if no environment is active. """ if "VIRTUAL_ENV" not in builtins.__xonsh__.env: return env_path = builtins.__xonsh__.env["VIRTUAL_ENV"] if env_path.startswith(self.venvdir): name = env_path[len(self.venvdir) :] if name[0] in "/\\": name = name[1:] return name else: return env_path
[docs] def activate(self, name): """ Activate a virtual environment. Parameters ---------- name : str Virtual environment name or absolute path. """ env = builtins.__xonsh__.env ve = self[name] if "VIRTUAL_ENV" in env: self.deactivate() type(self).oldvars = {"PATH": list(env["PATH"])} env["PATH"].insert(0, ve.bin) env["VIRTUAL_ENV"] = ve.env if "PYTHONHOME" in env: type(self).oldvars["PYTHONHOME"] = env.pop("PYTHONHOME") events.vox_on_activate.fire(name=name)
[docs] def deactivate(self): """ Deactivate the active virtual environment. Returns its name. """ env = builtins.__xonsh__.env if "VIRTUAL_ENV" not in env: raise NoEnvironmentActive("No environment currently active.") env_name = self.active() if hasattr(type(self), "oldvars"): for k, v in type(self).oldvars.items(): env[k] = v del type(self).oldvars env.pop("VIRTUAL_ENV") events.vox_on_deactivate.fire(name=env_name) return env_name
def __delitem__(self, name): """ Permanently deletes a virtual environment. Parameters ---------- name : str Virtual environment name or absolute path. """ env_path = self[name].env try: if self[...].env == env_path: raise EnvironmentInUse( 'The "%s" environment is currently active.' % name ) except KeyError: # No current venv, ... fails pass shutil.rmtree(env_path) events.vox_on_delete.fire(name=name)
def _get_vox_default_interpreter(): """Return the interpreter set by the $VOX_DEFAULT_INTERPRETER if set else sys.executable""" return builtins.__xonsh__.env.get("VOX_DEFAULT_INTERPRETER", sys.executable)