I need to install a package from PyPi straight within my script. Maybe there’s some module or distutils (distribute, pip etc.) feature which allows me to just execute something like pypi.install('requests') and requests will be installed into my virtualenv.

The officially recommended way to install packages from a script is by calling pip’s command-line interface via a subprocess. Most other answers presented here are not supported by pip. Furthermore since pip v10, all code has been moved to pip._internal precisely in order to make it clear to users that programmatic use of pip is not allowed.

Use sys.executable to ensure that you will call the same pip associated with the current runtime.

import subprocess
import sys

def install(package):
    subprocess.check_call([sys.executable, "-m", "pip", "install", package])

You can also use something like:

import pip

def install(package):
    if hasattr(pip, 'main'):
        pip.main(['install', package])
    else:
        pip._internal.main(['install', package])

# Example
if __name__ == '__main__':
    install('argh')

If you want to use pip to install required package and import it after installation, you can use this code:

def install_and_import(package):
    import importlib
    try:
        importlib.import_module(package)
    except ImportError:
        import pip
        pip.main(['install', package])
    finally:
        globals()[package] = importlib.import_module(package)


install_and_import('transliterate')

If you installed a package as a user you can encounter the problem that you cannot just import the package. See How to refresh sys.path? for additional information.

This should work:

import subprocess

def install(name):
    subprocess.call(['pip', 'install', name])

i added some exception handling to @Aaron’s answer.

import subprocess
import sys

try:
    import pandas as pd
except ImportError:
    subprocess.check_call([sys.executable, "-m", "pip", "install", 'pandas'])
finally:
    import pandas as pd

You define the dependent module inside the setup.py of your own package with the “install_requires” option.

If your package needs to have some console script generated then you can use the “console_scripts” entry point in order to generate a wrapper script that will be placed within the ‘bin’ folder (e.g. of your virtualenv environment).