he-kit 0.0.9

A project generator that bootstraps a FastAPI setup following Helicon's standards and best practices.

Helicon kit

A project generator that bootstraps a FastAPI setup following Helicon's standards and best practices.

Included tools

These are the major tools that are configured and included in the project:

• structlog
• sqlmodel
• alembic
• fastapi
• pydantic-settings
• pytest

Start a new project

Run the following commands to initialize a new project:

mkdir helicon-app
cd helicon-app
uvx he-kit init

After answering the prompts you should have a fully runnable FastAPI setup:

├── alembic.ini
├── Dockerfile
├── main.py
├── pyproject.toml
├── README.md
├── migrations
│   ├── env.py
│   ├── script.py.mako
│   └── versions
│       └── placeholder.txt
├── src
│   └── helicon_app
│       ├── app.py
│       ├── conf.py
│       ├── __init__.py
│       ├── models
│       │   └── __init__.py
│       ├── routers
│       │   └── __init__.py
│       └── schemas
│           └── __init__.py
└── tests
    └── conftest.py

You can verify that it works by running the test suite and starting the development server:

uv run pytest
uv run he-kit dev

It is recommended that you synchronize the new environment and install the supplied pre-commit hooks (mypy and ruff):

uv sync
uv run pre-commit install

Create a model and migrations

Helicon-kit uses SQLModel and Alembic. To start working with models, first create a new module in the models/ directory. We'll call it models/users.py:

from sqlmodel import Field, SQLModel


class User(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str
    email: str

We have to make sure the models are importable via your_module_name.models in order for Alembic to discover them. We do this by importing the new module in models/__init__.py:

from .users import *

Create the migrations and apply them:

uv run he-kit makemigrations "add user model"
uv run he-kit migrate

Create and register a new router

Firstly we need to define some API schemas. We'll add them in the module schemas/users.py:

from sqlmodel import SQLModel


class UserCreate(SQLModel):
    name: str
    email: str


class UserRead(SQLModel):
    id: int
    name: str
    email: str

Note: as both schemas and models are derrived from SQLModel you can of course create base classes and extend them to avoid repeating attributes.

We'll continue and a new module in the routers/ directory. We'll stay on the theme and call it routers/users.py:

from he_kit.core.db import db_session
from fastapi import APIRouter, Depends
from sqlalchemy.ext.asyncio import AsyncSession
from sqlmodel import select

from ..models.users import User
from ..schemas.users import UserCreate, UserRead

router = APIRouter()


@router.get("/", response_model=list[UserRead])
async def list_users(session: AsyncSession = Depends(db_session)):
    result = await session.execute(select(User))
    users = result.scalars().all()
    return users


@router.post("/", response_model=UserRead)
async def create_user(user: UserCreate, session: AsyncSession = Depends(db_session)):
    user = User.model_validate(user)
    session.add(user)
    await session.commit()
    await session.refresh(user)
    return user

And finally we register the router in app.py:

from he_kit.core.app import App

from .conf import settings
from .routers.users import router as user_router


def create_app():
    app = App(settings=settings)

    app.include_router(user_router, prefix="/users")

    return app


app = create_app()

Writing tests

To verify that everything works we'll create a testmodule in tests/test_user_endpoints.py:

def test_create_user(client):
    payload = {"name": "Alice", "email": "[e-mail]"}
    r = client.post("/users/", json=payload)
    assert r.status_code == 200
    data = r.json()
    assert data["name"] == "Alice"
    assert data["email"] == "[e-mail]"
    assert "id" in data


def test_list_users(client):
    payload = {"name": "Bob", "email": "[e-mail]"}
    r = client.post("/users/", json=payload)
    assert r.status_code == 200

    r = client.get("/users/")
    assert r.status_code == 200
    users = r.json()
    assert any(u["name"] == "Bob" for u in users)

Save the file and run the tests suite:

uv run pytest

Local development setup

To install he-kit from local disk to try it out during development, you can install it with pip:

mkdir test-dir
cd test-dir
uv venv
pip install -e ../path/to/he-kit
uv run he-kit ...