runemalm / ddd-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.

Read the user guide in the documentation to get started. You can also look at the example code of the 'shipping' context.

Star and/or follow the project to receive notifications when version 1.0.0 is released.

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(
            app_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:

You can find the latest documentation at readthedocs.

Contribution:

If you want to contribute to the code base, create a pull request on the develop branch.

Release Notes:

0.9.5 - 2022-03-13

• Added documentation.
• Moved db_service related classes.
• Moved event related classes.
• Added MemoryPostgresDbService to be able to run tests against an in-memory postgres database.
• Fixed bug: container kwarg in example main.py (thanks euri10).

0.9.4 - 2021-05-17

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

0.9.3 - 2021-03-27

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

0.9.2 - 2021-03-15

• Fixed bug: Env file wasn't loaded in certain circumstances.

0.9.1 - 2021-03-14

• Initial commit.