pip-services4-logic 0.0.5

Description:

pipservices4logic 0.0.5

Business Logic Components for Python
This module is a part of the Pip.Services polyglot microservices toolkit.
The Logic module contains standard component definitions to handle complex business transactions.
The module contains the following packages:

Cache - distributed cache
Lock - distributed lock components
State - distributed state management components

Quick links:

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Use
Install the Python package as
pip install pip_services4_logic

Example how to use caching and locking.
Here we assume that references are passed externally.
from pip_services3_commons.refer import Descriptor, References, IReferences, IReferenceable
from pip_services4_logic.cache import ICache, MemoryCache
from pip_services4_logic.lock.ILock import ILock
from pip_services4_logic.lock.MemoryLock import MemoryLock


class MyComponent(IReferenceable):
__cache: ICache
__lock: ILock

def set_references(self, references: IReferences):
self.__cache = references.get_one_required(Descriptor("*", "cache", "*", "*", "1.0"))
self.__lock = references.get_one_required(Descriptor("*", "lock", "*", "*", "1.0"))

def my_method(self, context, param1):
# First check cache for result
result = self.__cache.retrieve(context, 'mykey')

# Lock..
self.__lock.acquire_lock(context, "mykey", 1000, 1000, )

# Do processing
# ...

# Store result to cache async
self.__cache.store(context, 'mykey', result, 3600000)

# Release lock async
self.__lock.release_lock(context, 'mykey')

return result


# Use the component
my_component = MyComponent()
my_component.set_references(References.from_tuples(
Descriptor("pip-services", "cache", "memory", "default", "1.0"), MemoryCache(),
Descriptor("pip-services", "lock", "memory", "default", "1.0"), MemoryLock(),
))

result = my_component.my_method(None, param1)

If you need to create components using their locators (descriptors) implement
component factories similar to the example below.
from pip_services3_commons.refer import Descriptor
from pip_services4_components.build import Factory


class MyFactory(Factory):
my_component_descriptor = Descriptor("myservice", "mycomponent", "default", "*", "1.0")

def __init__(self):
super(MyFactory, self).__init__()

self.register_as_type(MyFactory.my_component_descriptor, MyFactory)


# Using the factory
my_factory = MyFactory()
my_component1 = my_factory.create(Descriptor("myservice", "mycomponent", "default", "myComponent1", "1.0"))
my_component2 = my_factory.create(Descriptor("myservice", "mycomponent", "default", "myComponent2", "1.0"))

...

Develop
For development you shall install the following prerequisites:

Python 3.7+
Visual Studio Code or another IDE of your choice
Docker

Install dependencies:
pip install -r requirements.txt

Run automated tests:
python test.py

Generate API documentation:
./docgen.ps1

Before committing changes run dockerized build and test as:
./build.ps1
./test.ps1
./clear.ps1

Contacts
The initial implementation is done by Sergey Seroukhov. Pip.Services team is looking for volunteers to
take ownership over Python implementation in the project.