Install Kodi Python plugin dependencies from PyPI using pip

deps.py

# Use as
# 
#     import deps
#
#     deps.install(dict(requests="2.28.1"))
#

import json
import os
import site
import subprocess
import sys
import typing as t
from contextlib import contextmanager
from pathlib import Path

HERE = Path(__file__).parent
VENV_PREFIX = HERE / ".venv"


@contextmanager
def metadata() -> t.Iterator[dict]:
    """Load and persist metadata."""
    METADATA = HERE / ".metadata.json"

    md = json.loads(METADATA.read_text()) if METADATA.exists() else {}
    yield md
    METADATA.write_text(json.dumps(md, indent=4))


ENV = os.environ.copy()
path = ENV.get("PATH", None)

ENV["PATH"] = (
    os.pathsep.join(
        [
            str(VENV_PREFIX / "bin"),
            path,
        ]
    )
    if path is not None
    else str(VENV_PREFIX / "bin")
)


def create_venv() -> None:
    """Create a virtual environment.

    Return the environment variables required to use the virtual environment.
    """
    subprocess.run(
        [
            sys.executable,
            "-m",
            "venv",
            str(VENV_PREFIX),
        ],
        check=True,
    )

    subprocess.run(
        [
            "pip",
            "install",
            "--upgrade",
            "pip",
        ],
        check=True,
        env=ENV,
    )


def install(dependencies: t.Dict[str, str]) -> None:
    with metadata() as md:
        # Check if venv has been created
        if not md or md.get("venv") != str(VENV_PREFIX):
            create_venv()
            md["venv"] = str(VENV_PREFIX)

        # Check if dependencies need to be installed
        if not md or md.get("dependencies", {}) != dependencies:
            subprocess.run(
                [
                    # "python",
                    # "-m",
                    "pip",
                    "--disable-pip-version-check",
                    "install",
                    "--no-warn-script-location",
                    "--prefix",
                    str(VENV_PREFIX),
                    *("==".join(d) for d in dependencies.items()),
                ],
                check=True,
                env=ENV,
            )

            # Persist dependency information to avoid reinstalling next time
            md["dependencies"] = dependencies

    # Ensure that the dependency prefix is added to the path so that we can
    # import the newly installed dependencies.
    sys.path[0:0] = site.getsitepackages(prefixes=[str(VENV_PREFIX)])