dypend

dypend Load dependent libraries dynamically.

A few days ago, I encountered many users feedback in an open source project. The Problem is they can not install the dependencies, such as execute pip install -r requirements.txt but nothing happened.

There are many problems like the wrong config of env that can cause this result and it's troublesome to check them one by one.

To solve this problem once and for all, we usually go to site-packages and put the required packages in the project root directory.

it's crude, not elegant.

So I wanted to load packages dynamically. if package do not exist, use pip to download them.

I searched Google roughly, it seems no one have mention this method, and I feel it's convenient to use, so I share it.

Although dypend is packaged for everyone to download, however that it depends on pip, which is against the intention of doing dynamic dependencies.

So I recommend using the Quick Start - Run by injecting code approach

Quick start

Run by pip install

Download the dypend package from PyPI .

pip install dypend

Freeze requirements.txt file.

pip freeze > requirements.txt

import dypend at the top of the project's entry file, without changing any other code.

import dypend

dypend will check packages in requirements.txt is available or not in your Python environment, if not, dypend will call pip to download them.

Run by injecting code

Freeze requirements.txt file.

pip freeze >  requirements.txt

Add the following code to the top of the project's entry file, without changing any other code.

import os
import re
REQUIREMENTS = os.getcwd() + '/requirements.txt'
def getDepends():
    requirements = open(REQUIREMENTS, 'r')
    libs = requirements.readlines()
    libList = []
    for lib in libs:
        try:
            name = re.search("^.+(?===)", lib).group(0)
            version = re.search("(?<===).+$", lib).group(0)
            libDict = {
                "name": name,
                "version": version
            }
            libList.append(libDict)
        except:
            continue
    return libList
def importLib():
    """Load python dependent libraries dynamically"""

    libList = getDepends()

    from pip._internal import main as pip_main
    import importlib

    def install(package):
        pip_main(['install', package])

    createVar = locals()

    for lib in libList:
        print(lib)
        try:
            createVar[lib["name"]] = importlib.import_module(lib["name"])
        except Exception as e:
            try:
                install(f'{lib["name"]}=={lib["version"]}')
                createVar[lib["name"]] = importlib.import_module(lib["name"])
            except Exception as e:
                print(e)
importLib

dypend will check packages in requirements.txt is available or not in your Python environment, if not, dypend will call pip to download them.