LazImp, The "don't wait for it..." package

LazImp is a package that allows lazy loading of python modules, packages and symboles for python 3.10+. This package allows you to load modules and packages only when the user use it. From dynamic import to "I only need this function, not the whole framework", the start-up time is speed-up and delayed over the execution of the software.

Using LazImp, you will reduce the memory usage and the start-up time of your software.

Example

First, you may have long loading or memory heavy modules to expose in your package api:

# package/heavy_module.py
print('Heavy module is loading...')
from time import sleep

sleep(10)
print('heavy_module loaded')

But instead of importing them directly, you can do a lazy import in the __init__.py:

# package/__init__.py of a package
import lazimp

math: lazimp.ModuleType
heavy_module: lazimp.ModuleType

__getattr__ = lazimp.lazy_import(
    'math',
    heavy_module='package',
)

Now, when you import the package:

# main.py
import package

print('Before access to heavy_module')
print(package.heavy_module)
print('After access to heavy_module')
print('Before access to math')
print(package.math)
print('After access to math')

And the output:

Before access to heavy_module
Heavy module is loading...
(wait 10 sec)
heavy_module loaded
<module 'heavy_module' from '...'>
After access to heavy_module
Before access to math
# math loaded
<module 'math' (built-in)>
After access to math

Without the lazy loading of heavy_module.py, the output would have been:

Heavy module is loading...
(wait 10 sec)
heavy_module loaded  # math loaded too
Before access to heavy_module
<module 'heavy_module' from '...'>
After access to heavy_module
Before access to math
<module 'math' (built-in)>
After access to math

Why this name: LazImp?

lazimp is a portmanteau of lazy and imp.

imp was the name of the module importlib before python 3.4 and its deprecation: What's new in Python 3.4: Deprecations in the Python API

The name could have been lazy_import but the imp part was preferred as a reference to the original module and because an imp with sunglasses and cocktail is cool 😎, and lazy shorten because it sounded better.