Run pip programmatically

pip_prog.py

from contextlib import contextmanager
from contextlib import redirect_stdout as r_stdout
from contextlib import redirect_stderr as r_stderr
from io import StringIO

import pip


def pip_exec(*args):
    with StringIO() as stdout, StringIO() as stderr:
        with r_stdout(stdout), r_stderr(stderr):
            code = pip.main(list(args))
        return code, stdout.getvalue(), stderr.getvalue()


def raise_on_nonzero(code, stdout, stderr, exc=RuntimeError):
    if code:
        raise exc("pip failed", code, stdout, stderr)
    else:
        return code, stdout, stderr


@contextmanager
def pip_install(*args):
    raise_on_nonzero(*pip_exec("install", *args))
    yield


if __name__ == "__main__":
    with pip_install("requests", "pyzmq"):
        import requests
        import zmq