dynamic-factory 0.1.9

This module contain dynamic implementations of factory pattern

Table of content

• Table of content
• Overview
• Installation
• Usage tutorial
  • Setup
  • Quick start
  • Groups
  • Functions with arguments
  • Aliases
• Limitations
• ToDo

Overview

dynamic_factory is package for dynamic implementations of factory pattern. Currently it has implemented only one class. FuncFactory that is designed to work with functions. Project repo can be found on github page and package can be found on pypi page.

Installation

Via pip:

pip install dynamic-factory

Via poetry:

poetry add dynamic-factory

Usage tutorial

Setup

Lets define two python files ./src1.py and ./src2.py

# ./src1.py
def func1():
    print("greetings from src1 func1")


def func2(arg):
    print(f"greetings from src1 func2 with arg {arg}")


def func12():
    print("greetings from src1 func12")


def unregistered_func(arg):
    print(f"greetings from src1 unregistered_func with arg {arg}")
    
# ./src2.py
def func1():
    print("greetings from src2 func1")

def func2(arg):
    print(f"greetings from src2 func2 with arg {arg}")

Quick start

If you want to register those functions in factory, decorate them with @FuncFactory.register() method.
It has two arguments

• alias optional identifier that you can use instead of function name to execute function from factory level
• group help distinguish which factory should register which function. If you use only one factory, don't have to change it. After that functions will be visible from factory.

# ./src1.py
from dynamic_factory import FuncFactory


@FuncFactory.register()
def func1():
    print("greetings from src1 func1")


@FuncFactory.register(group="TWO")
def func2(arg):
    print(f"greetings from src1 func2 with arg {arg}")


@FuncFactory.register()
@FuncFactory.register(group="TWO")
def func12():
    print("greetings from src1 func12")


def unregistered_func(arg):
    print(f"greetings from src1 unregistered_func with arg {arg}")
    
# ./src2.py
from dynamic_factory import FuncFactory


@FuncFactory.register(alias="src2_func1")
def func1():
    print("greetings from src2 func1")

@FuncFactory.register(alias="func_two", group="TWO")
def func2(arg):
    print(f"greetings from src2 func2 with arg {arg}")

To create factory simply initialize FuncFactory object.

from dynamic_factory import FuncFactory
import src1
import src2


base_factory = FuncFactory([src1])
print(
    "base factory registered aliases:", 
    *base_factory.registered_aliases
)

for alias in base_factory.registered_aliases:
    base_factory.execute(alias)

base factory registered aliases: func1 func12
greetings from src1 func1
greetings from src1 func12

Note that base_factory don't recorded functions from src2, thats happened because scr2 was not passed as argument in initialization. To fix that just extend modules list:

func1_factory = FuncFactory([src1, src2])
print(
    "func1 factory registered aliases:", 
    *func1_factory.registered_aliases
)

for alias in func1_factory.registered_aliases:
    func1_factory.execute(alias)

func1 factory registered aliases: func1 func12 src2_func1
greetings from src1 func1
greetings from src1 func12
greetings from src2 func1

Groups

Factories only register functions that belong to the same group as factory. If you want create more factories it may be good practice to define new groups. To define new group simply pass new unique string in register decorator. If you wish to create single function that belong to two group simply add two decorators like in ./src1.py:func12 example.

func2_factory = FuncFactory([src1, src2], group="TWO")
print(
    "func2 factory registered aliases:", 
    *func2_factory.registered_aliases
)

func2_factory.execute("func12")

func2 factory registered aliases: func12 func2 func_two
greetings from src1 func12

Functions with arguments

If you want execute functions with arguments pass them to FuncFactory.execute function as args and kwargs

func2_factory.execute("func2", "argument")
func2_factory.execute("func_two", arg=123)

greetings from src1 func2 with arg argument
greetings from src2 func2 with arg 123

Aliases

Default alias for function is its name. but if you prefer it is possible to change it during registration process with alias param. Sometimes it is necessary like in ./src2.py:func1 because it has the same name as ./src1.py:func1, so without alias those functions would overwrite each other.

Limitations

Current implementation is adding field to functions that store record metadata, keep it in mind if you would do some advanced function manipulations like iteration trough func.__dict__

ToDo

• Warn user if he have the same alias for two different functions.
• implement __getitem__ that will access to factory function by alias.