pypi package installation fails without root access

[chfw]

python3 -m moban -m mobanfile
Collecting pypi-mobans-pkg
Downloading https://files.pythonhosted.org/packages/eb/ae/596498079f9036ed90ddd743e6c9e90066826ea6c510ecd71f9ac6e183e7/pypi_mobans_pkg-0.0.5-py2.py3-none-any.whl (128kB)
|████████████████████████████████| 133kB 926kB/s
Requirement already satisfied: lml in /home/python3.7/lib/python3.7/site-packages (from pypi-mobans-pkg) (0.0.9)
Installing collected packages: pypi-mobans-pkg
ERROR: Could not install packages due to an EnvironmentError: [Errno 13] Permission denied: '/usr/lib/python3.7/site-packages/pypi_mobans_pkg'
Consider using the --user option or check the permissions.

Yes, this obviously is not a bug for scenarios when people are doing everything inside a virtualenv.

So , need to try without --user first, then fallback to with --user , or ...

moban could manage its own packages inside ~/.cache/moban/packages/ and add that to the PYTHONPATH / sys.path

moremoban/moban#278

[chfw]

Had a read on: https://docs.python.org/3/install/index.html#alternate-installation-the-user-scheme

[chfw]

My reservation is: what if the package is not found, subprocess call will also fail, which then triggers an additional bound-to-fail call to install on '--user'.

[chfw]

>>> import os
>>> import subprocess
>>> import sys
>>> subprocess.check_call([sys.executable, "-m", "pip", "install", "pypi-mobans-pkgx"])
ERROR: Could not find a version that satisfies the requirement pypi-mobans-pkgx (from versions: none)
ERROR: No matching distribution found for pypi-mobans-pkgx
WARNING: You are using pip version 20.0.2; however, version 20.1 is available.
You should consider upgrading via the '/Users/jaska/github/moremoban/moban-env/bin/python -m pip install --upgrade pip' command.
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/subprocess.py", line 347, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['/Users/jaska/github/moremoban/moban-env/bin/python', '-m', 'pip', 'install', 'pypi-mobans-pkgx']' returned non-zero exit status 1.