Architecture

architecture: onion architecture

architecture image

==================   ====================
|  presentation  |   |  infrastructure  |
==================   ====================
        |                   |         | 
        ▼                   ▽         |
===============================       |
|          use case           |       |
===============================       |
        |                             |
        ▼                             ▽
=========================================
|                domain                 |
=========================================

memo. ▼ : call or use ▽ : implement

App Package Composition

<directory>       <content(layer>
presentation   -> routers (controller)
usecase        -> appservice (application_service)
 - XXX_usecase        --- applicatiion service called presentation layer
 - XXX_queryservice   --- query service interface
domain         -> domain (entity, value_object)
 |-entity           --- domain model
 |-value_object     --- value object <ex> validataion check
 |-repository   --- repository interface
infrastracture -> infrastracture
 |-queryservice   --- query service implements
 |-repository   --- repository implements
models  --- table definition 
schemas --- response schemas

CQRS repository pattern

reference doc :https://iktakahiro.dev/python-ddd-onion-architecture#heading-cqrs-pattern

• query: query service (pass domain) usecase -> usecase-queryservice(interface) -> infrastructure-queryservice(implement)
• Command: repository service usecase -> domain-repository (interface) -> infrastructure-repository(implement)

modelの操作が不要のときはシンプルにクエリーサービスを利用し、 データの保存などdomainモデルの操作が必要ならdomain層(repository)を使う

promises

• think domain center , otherwise start domain modeling
• dependence is absolutely protected

Getting start

Setting some files

Pip library install

• pipenv install

$ pipenv --python 3.10
$ pipenv install --three fastapi fastapi-sqlalchemy sqlalchemy_utils mysqlclient pytest inject pydantic alembic uvicorn sqlalchemy

Create docker/api/requirements.txt

$ pipenv requirements > docker/api/requirements.txt

Alembic init

$ cd db $ alembic init migrations -> create maigration directory

• Please edit file of "alembic.ini" "Comment out below code" sqlalchemy.url = driver://user:pass@localhost/dbname

Edit almebic/env.py

Edit "migrations/env.py" quote -> "db/samples/env.py" Please edit env.py while referring to sample/env.py and edit parts are belows. -- added code here -- -- changed code here --

Preparing seed file

cp samples/seed.py ./seed.py

Build & Start Docker container

Create docker network

$ docker network create fastapi_network

Rebuild & run api & db container

$ docker-compose build
$ docker-compose up

• try connect http://localhost:8888/docs

DB Migration

# enter api container
 $ docker-compose run api bash
  or
 $ docker ps
 $ docker exec -it XXX bash
   (*)xxx: container id
 
 $ cd /usr/src/app/db

# create maigration file
 $ alembic revision --autogenerate -m "create users, tasks"
  -> db/migrations/versions/~~~_comment
# maigrate
 $ alembic upgrade head

Insert DB with seed file.

!!! run on docker in api container

# enter api container
 $ cd /usr/src/app/db
 $ python seed.py

Access to fast-api.

• try connect http://localhost:8888/docs

Chips

how to login mysql

$ docker-compose run api bash
$ cd /usr/src/app/db  
> mysql -h"$MYSQL_HOST" -u"$MYSQL_USER" -p"$MYSQL_PASSWORD"
> use test_db

stop container running with docker-compose

$ docker ccompose down

how to use case migration methods

• the first migrate
  $ alembic upgrade head
• step by step upgrade
  $ alembic upgrade +1
• downgrade
  $ alembic downgrade -1
  if you remake migration file, delete migration file
• all reset
  $ alembic downgrade base

Reference Documents

• Fast API Router
  • https://fastapi.tiangolo.com/tutorial/bigger-applications/
• FastAPI 入門
  • https://zenn.dev/sh0nk/books/537bb028709ab9/viewer/86648d
• 参考にしたパッケージ構成
  • https://zenn.dev/yusugomori/articles/a3d5dc8baf9e386a58e5
• 参考にした考え方とソース
  • https://speakerdeck.com/iktakahiro/ddd-and-onion-architecture-in-python?slide=57
  • https://github.com/iktakahiro/dddpy