ddd-for-python 0.9.4

A domain-driven design (DDD) framework for Python.

DDD for Python

This is a framework for developing apps based on domain-driven design. The design is inspired by Vaughn Vernon's reference implementation of DDD in Java. A little bit of inspiration also comes from django.

Purpose:

The goal of this project is to provide a complete framework for implementing DDD bounded contexts in Python.

Full documentation will be available in version 1.0.0. There's a code example for a 'shipping' context in the 'examples' folder you can look at meanwhile.

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Design:

The design is based on these patterns:

• DDD (collection of patterns)
• Hexagonal Architecture
• Near-infinite Scalability ("Entity" concept)
• xUnit (for testing)

Theory:

The following sources are recommended:

• Domain-Driven Design: Tackling Complexity in the Heart of Software - Eric Evans
• Implementing Domain-Driven Design - Vaughn Vernon
• Hexagonal Architecture - Alistair Cockburn
• Life Beyond Distributed Transactions - Pat Helland
• xUnit - Wikipedia

Supported Python Versions:

• Tested with python 3.8.5.
• Should work with any version >= 3.8.0 (not tested).

Installation:

$ pip install ddd-for-python

Example:

# This is the "main.py" file that
# starts the bounded context in a container.

from ddd.application.config import Config
from ddd.infrastructure.container import Container

from shipping.utils.dep_mgr import DependencyManager
from shipping.application.shipping_application_service import \
    ShippingApplicationService


if __name__ == "__main__":
    """
    This is the container entry point.    
    Creates the application service and runs it in the container.
    """

    # Config
    config = Config()

    # Dependency manager
    dep_mgr = \
        DependencyManager(
            config=config,
        )

    # Application service
    service = \
        ShippingApplicationService(
            customer_repository=dep_mgr.get_customer_repository(),
            db_service=dep_mgr.get_db_service(),
            domain_adapter=dep_mgr.get_domain_adapter(),
            domain_publisher=dep_mgr.get_domain_publisher(),
            event_repository=dep_mgr.get_event_repository(),
            interchange_adapter=dep_mgr.get_interchange_adapter(),
            interchange_publisher=dep_mgr.get_interchange_publisher(),
            job_adapter=dep_mgr.get_job_adapter(),
            job_service=dep_mgr.get_job_service(),
            log_service=dep_mgr.get_log_service(),
            scheduler_adapter=dep_mgr.get_scheduler_adapter(),
            shipment_repository=dep_mgr.get_shipment_repository(),
            max_concurrent_actions=config.max_concurrent_actions,
            loop=config.loop.instance,
        )

    # ..register
    dep_mgr.set_service(service)

    # Container
    container = \
        Container(
            service=service,
            log_service=dep_mgr.get_log_service(),
        )

    # ..run
    loop = config.loop.instance
    loop.run_until_complete(container.run())
    loop.close()

For the full code, see: "examples/webshop/shipping".

Documentation:

The documentation is coming shortly.

Release Notes:

0.9.4 - 2021-05-17

• Add 'context' to log service's log messages.
• Move record filtering methods to base repository class.
• Add 'uses_service' to Task class. Deprecate 'makes_requests'.

0.9.3 - 2021-03-27

• Search env file from cwd by default in tests, (when no path specified).
• Refactor Task class to make it more simple.
• Refactor the configuration solution by adding a Config class.
• Add example code for 'shipping' context of a webshop application.
• Add get_all_jobs() and get_job_count() to scheduler adapter & service.
• Add missing call to _migrate() in a couple of Repository class functions.

0.9.2 - 2021-03-15

• Fix a bug where env file wasn't loaded in certain circumstances.

0.9.1 - 2021-03-14

• First release.