get the installed path of package rather than module

[zhouzaida]

I implement a helper function to get the installed path of a package rather than a module.
However, the performance is so slow.

import os.path as osp
from pkg_resources import get_distribution

def get_installed_path(package: str) -> str:
    pkg = get_distribution(package)
    possible_path = osp.join(pkg.location, package)
    if osp.exists(possible_path):
        return possible_path
    else:
        if pkg.has_metadata('top_level.txt'):
            module_name = pkg.get_metadata('top_level.txt').split('\n')[0]
            return osp.join(pkg.location, module_name)
        else:
            raise ValueError(f'can not get the installed path of {package}')

>>> get_installed_path('mysql-python')
'.../lib/python3.7/site-packages/MySQLdb'
>>> get_installed_path('python-memcached')
'.../lib/python3.7/site-packages/memcache'

[webknjaz]

Is there a question somewhere in this statement?

The only thing I'll mention is that today it's best to use importlib.metadata in most places where you'd use pkg_resources in the past.

[zhouzaida]

Thanks for your quick reply. Yet, the above code has an issue and I fixed it.

In fact, the name of a package is not always the same as its module name(https://stackoverflow.com/questions/11453866/given-the-name-of-a-python-package-what-is-the-name-of-the-module-to-import).

If we want to get the installed path of a package, we should know the module name to concatenate the pkg.location and module_name.

In addition, importlib.metadata is a new feature of python3.8 but my python is 3.6

[zhouzaida]

I provide two cases here.

I implement a helper function to get the installed path of a package rather than a module.
However, the performance is so slow.

import os.path as osp
from pkg_resources import get_distribution

def get_installed_path(package: str) -> str:
    pkg = get_distribution(package)
    possible_path = osp.join(pkg.location, package)
    if osp.exists(possible_path):
        return possible_path
    else:
        if pkg.has_metadata('top_level.txt'):
            module_name = pkg.get_metadata('top_level.txt').split('\n')[0]
            return osp.join(pkg.location, module_name)
        else:
            raise ValueError(f'can not get the installed path of {package}')

>>> get_installed_path('mysql-python')
'.../lib/python3.7/site-packages/MySQLdb'
>>> get_installed_path('python-memcached')
'.../lib/python3.7/site-packages/memcache'

[webknjaz]

If we want to get the installed path of a package, we should know the module name to concatenate the pkg.location and module_name.

True.

In addition, importlib.metadata is a new feature of python3.8 but my python is 3.6

Yes. That's why a compat project called importlib_metadata exists on PyPI. Use it as a fallback.

[zhouzaida]

Thanks very much. I have a try

[zhouzaida]

Thanks very much. It is very helpful.