pep582install.py

#!/usr/bin/env python3

# This is a small single file tool to implement PEP 582 as an external hack.
# Read https://www.python.org/dev/peps/pep-0582/ for more details.

import os
import sys
import site
import argparse


def install():
    "To install in the users site-packaes directory"

    site_path = os.path.join(site.getusersitepackages(), "pep582.py")
    site_pth = os.path.join(site.getusersitepackages(), "pep582.pth")
    data = ""
    with open(__file__) as fobj:
        data = fobj.read()

    try:
        os.makedirs(site.getusersitepackages())
    except FileExistsError:
        # This means we already have the directory in place
        pass

    with open(site_path, "w") as fobj:
        fobj.write(data)

    with open(site_pth, "w") as fobj:
        fobj.write("import pep582;pep582.enable_local_pypackages()\n")

    print(f"Successfully installed in {site_path}")


def enable_magic(pypackages_path: str):
    """Enables our __pypackages__ if exits, also tells pip where to install

    """
    major = sys.version_info.major
    minor = sys.version_info.minor
    libname = "lib"
    # On Windows the spelling is capital Lib inside of the PIP_PREFIX
    if os.name == "nt":
        libname = "Lib"
    if os.path.exists(pypackages_path):
        os.environ["VIRTUAL_ENV"] = pypackages_path
        site_packages_path = os.path.join(
            pypackages_path, libname, f"python{major}.{minor}", "site-packages"
        )
        if os.name == "nt":
            site_packages_path = os.path.join(
                pypackages_path, libname, "site-packages"
            )
        sys.path.insert(1, site_packages_path)
        if sys.argv[0] == "-m":
            # let us try to fix pip here
            os.environ["PIP_PREFIX"] = pypackages_path


def enable_local_pypackages():
    """Function to use local __pypackages__ if not running via a script.
    """
    pwd = os.getcwd()
    if sys.argv[0] == "" or sys.argv[0] == "-m":  # Means python3
        pypackages_path = os.path.join(pwd, "__pypackages__")
        # check for the existance
        enable_magic(pypackages_path)
    else:
        basedir = os.path.dirname(sys.argv[0])
        pypackages_path = os.path.join(basedir, "__pypackages__")
        # check for the existance
        enable_magic(pypackages_path)


def main():
    """The main entry point.
    """
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "--install",
        action="store_true",
        help="Install the tool to users' site-packages directory",
    )
    args = parser.parse_args()

    if args.install:
        install()


if __name__ == "__main__":
    main()