Develop Reference

Checking if a package is installed specifically via pip

Checking if a particular package is available from within Python can be done via
try:
import requests
except ImportError:
available = False
else:
available = True
Additionally, I would like to know if the respective package has been installed with pip (and can hence been updated with pip install -U package_name).
Any hints?

I believe one way to figure out if a project has been installed by pip is by looking at the content of the INSTALLER text file in the distribution's dist-info directory for this project. With pkg_resources from setuptools this can be done programmatically like the following (error checking omitted):
import pkg_resources
pkg_resources.get_distribution('requests').get_metadata('INSTALLER')
This would return pip\n, in case requests was indeed installed by pip.

You said subprocess.call() is allowed, so
available = not(subprocess.call(["pip", "show", "requests"]))

No module named 'bankdate'(How to import just .py??)

Sorry that I have no idea how to describe this situation. The bigger package I like to install is "finance" (http://pydoc.net/finance/0.2502/finance.bankdate/). I downloaded it and unzipped to install using python setup.py install.
However, I cannot resolve importing another sub-module
bankdate(.py)
When I use finance module, there comes the error message, "ImportError: No module named 'bankdate'.(It is required in "__init__.py" under finance.) bankdate.py seems to be file under finance folder. How could I install "bankdate"?? Does anybody help me with this??
Thank you~!
cf) pip install bankdate, easy_install bankdate don't work in this case.

I do not know if you are working with Linux or Windows. But it would be a good start checking if the package was installed properly. You could use the following code to check installed packages and its versions:
import pip
installed_packages = pip.get_installed_distributions()
installed_packages_list = sorted(["%s==%s" % (i.key, i.version)
for i in installed_packages])
print(installed_packages_list)
By doing so packages installed using both setuptools and pip will appear in a list below. If your package does not appear in the list there you have, it was not installed.
Neverhteless try to import the module usign this:
from finance import bankdate
And see if the error continue. Hope it helps.

you can use pip install finance or you can download .whl file use pip intsall .whl
you can try

gmpy2 installs but can't find libmpc.so.3

I want to use gmpy2 with python 2.7 but when I try to import it I get:
>>> import gmpy2
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: libmpc.so.3: cannot open shared object file: No such file or directory
I installed gmpy2 using pip: pip install -user gmpy2 and the install looks ok apart from saying
Could not find .egg-info directory in install record for gmpy2
but after that it says that the install was a success.
I have installed MPC (1.0.3), GMP (6.1.1) and MPFR (3.1.4) and they all work, by which I mean I can call gcc foo.c -lmpc and gcc bar.c -lmpfr and the code compiles and works as expected. I've also got gmpy working using pip install. I think the problem will be to do with them not being installed in the default directories as I don't have sudo rights.
The directory where libmpc.so.3 is located is in the gcc call that pip spits out, I've also set CPATH and CPPFLAGS to look in my_prefix/include and LDFLAGS to look my_prefix/lib.
I don't really want to use the functionality from MPC so if there's a simple option to not install that part of gmpy2 I'd be happy with that.
I'm really confused, I've had it that pip fails to build a library and I've gone away and installed dependencies but normally once a library is passed pip it works.

I maintain gmpy2 and there are a couple of command line options that can be passed to setup.py that may help. I can't test the pip syntax right now but here are some options:
--shared=/path/to/gmp,mpfr,mpc will configure gmpy2 to load the libraries from the specified directory.
--static or --static=/path/to/gmp,mpfr,mpc will create a statically linked version of gmpy2 if the proper libraries can be found.
You can also try a build using setup.py directly. It may produce better error messages. Again, untested command:
python setup.py build_ext --static=/path/to/gmp,mpfr,mpc should compile a standalone, staticly linked gmpy2.so which will need to moved to the appropriate location.
Update
I've been able to test the options to pip.
If you are trying to use versions of GMP, MPFR, and MPC that are not those provided by the Linux distribution, you will need to specify the location of the new files to the underlying setup.py that is called by pip. For example, I have updated versions installed locally in /home/case/local. The following command will configure gmpy2 to use those versions:
pip install --install-option="--shared=/home/case/local" --user gmpy2
To compile a statically linked version (for example, to simplify distribution to other systems in cluster), you should use the following:
pip install --install-option="--static=/home/case/local" --user gmpy2
setup.py will use the specified base directory to configure the correct INCLUDE path (/home/case/local/include) and runtime library path (/home/case/local/lib).

Try to do the following as it might me fixed in an older version:
pip install --upgrade setuptools pip
pip uninstall gmpy2
pip install gmpy2

Pip freeze does not show repository paths for requirements file

I've created an environment and added a package django-paramfield via git:
$ pip install git+https://bitbucket.org/DataGreed/django-paramfield.git
Downloading/unpacking git+https://bitbucket.org/DataGreed/django-paramfield.git
Cloning https://bitbucket.org/DataGreed/django-paramfield.git to /var/folders/9Z/9ZQZ1Q3WGMOW+JguzcBKNU+++TI/-Tmp-/pip-49Eokm-build
Unpacking objects: 100% (29/29), done.
Running setup.py egg_info for package from git+https://bitbucket.org/DataGreed/django-paramfield.git
Installing collected packages: paramfield
Running setup.py install for paramfield
Successfully installed paramfield
Cleaning up...
But when i want to create a requirements file, i see only the package name:
$ pip freeze
paramfield==0.1
wsgiref==0.1.2
How can I make it output the whole string git+https://bitbucket.org/DataGreed/django-paramfield.git instead of just a package name? The package isn't in PyPi.
UPD: perhaps, it has to do something with setup.py? Should I change it somehow to reflect repo url?
UPD2: I found quite a similar question in stackoverflow, but the author was not sure how did he manage to resolve an issue and the accepted answer doesn't give a good hint unfortunately, though judging from the author's commentary it has something to do with the setup.py file.
UPD3: I've tried to pass download_url in setup.py and installing package via pip with this url, but he problem persists.

A simple but working workaround would be to install the package with the -e flag like pip install -e git+https://bitbucket.org/DataGreed/django-paramfield.git#egg=django-paramfield.
Then pip freeze shows the full source path of the package. It's not the best way it should be fixed in pip but it's working. The trade off -e (editing flag) is that pip clones the git/hg repo into /path/to/venv/src/packagename and run python setup.py deploy instead of clone it into a temp dir and run python setup.py install and remove the temp dir after the setup of the package.

Here's a script that will do that:
#!/usr/bin/env python
from subprocess import check_output
from pkg_resources import get_distribution
def download_url(package):
dist = get_distribution(package)
for line in dist._get_metadata('PKG-INFO'):
if line.startswith('Download-URL:'):
return line.split(':', 1)[1]
def main(argv=None):
import sys
from argparse import ArgumentParser
argv = argv or sys.argv
parser = ArgumentParser(
description='show download urls for installed packages')
parser.parse_args(argv[1:])
for package in check_output(['pip', 'freeze']).splitlines():
print('{}: {}'.format(package, download_url(package) or 'UNKNOWN'))
if __name__ == '__main__':
main()

This is an old question but I have just worked through this same issue and the resolution
Simply add the path to the repo (git in my case) to the requirements fie instead of the package name
i.e.
...
celery==3.0.19
# chunkdata isn't available on PyPi
https://github.com/aaronmccall/chunkdata/zipball/master
distribute==0.6.34
...
Worked like a charm deplying on heroku

getting python module complete version with pkg_resources

I made a python package using distutils that in its setup.py file, has:
setup(name = "foo",
version = "0.2.1",
...)
when I do:
import pkg_resources
pkg_resources.get_distribution("foo").version
I get 0.2 and not 0.2.1. Why is that? how can i get the full version? thank you.

pkg_resources looks for installed distributions in your Python installation. Have you re-ran python setup.py install or python setup.py develop after you’ve changed the version?
Try inspected the object returned by get_distribution for an attribute showing where the location is located on the file system; maybe foo is not installed where you think it is, and an older version is found instead.

It looks like a bug to me. If the package was installed with distutils instead of setuptools, then pkg_resources.get_distribution() returns the oldest version installed.
The best way to fix it is to replace:
from distutils.core import setup
with:
from setuptools import setup