Create simple todo app with FastAPI and SQLite

- Set up project structure and FastAPI application
- Create database models with SQLAlchemy
- Set up Alembic for database migrations
- Create API endpoints for todo CRUD operations
- Add health check endpoint
- Add unit tests for API endpoints
- Configure Ruff for linting and formatting

README.md

@@ -1,3 +1,92 @@
-# FastAPI Application
+# Simple Todo App
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+This is a FastAPI-based Todo application with SQLite as the database backend. The application provides a REST API for managing todo items.
+
+## Features
+
+- Create, read, update, and delete todo items
+- SQLite database for data persistence
+- Alembic for database migrations
+- Health check endpoint
+- API documentation with Swagger UI and ReDoc
+
+## Project Structure
+
+```
+├── alembic.ini                # Alembic configuration
+├── app                        # Application package
+│   ├── api                    # API routes
+│   │   ├── api.py             # Main API router
+│   │   └── endpoints          # API endpoints
+│   │       └── todos.py       # Todo endpoints
+│   ├── core                   # Core functionality
+│   │   └── config.py          # Application configuration
+│   ├── db                     # Database related modules
+│   │   └── session.py         # Database session management
+│   ├── models                 # SQLAlchemy models
+│   │   └── todo.py            # Todo model
+│   └── schemas                # Pydantic schemas
+│       └── todo.py            # Todo schemas
+├── main.py                    # Application entry point
+├── migrations                 # Alembic migrations
+│   ├── env.py                 # Alembic environment
+│   ├── README                 # Migrations README
+│   ├── script.py.mako         # Script template
+│   └── versions               # Migration versions
+│       └── 001_create_todos_table.py  # Initial migration
+├── requirements.txt           # Project dependencies
+└── tests                      # Tests
+    └── test_api.py            # API tests
+```
+
+## Getting Started
+
+### Prerequisites
+
+- Python 3.8 or higher
+
+### Installation
+
+1. Clone the repository
+
+2. Install dependencies:
+   ```bash
+   pip install -r requirements.txt
+   ```
+
+3. Run database migrations:
+   ```bash
+   alembic upgrade head
+   ```
+
+4. Start the application:
+   ```bash
+   uvicorn main:app --reload
+   ```
+
+5. Access the API documentation:
+   - Swagger UI: http://localhost:8000/docs
+   - ReDoc: http://localhost:8000/redoc
+
+## API Endpoints
+
+| Method | Endpoint     | Description                          |
+|--------|--------------|--------------------------------------|
+| GET    | /health      | Health check endpoint                |
+| GET    | /todos       | Get all todo items                   |
+| GET    | /todos/{id}  | Get a specific todo item             |
+| POST   | /todos       | Create a new todo item               |
+| PUT    | /todos/{id}  | Update an existing todo item         |
+| DELETE | /todos/{id}  | Delete a todo item                   |
+
+## Testing
+
+Run tests with pytest:
+
+```bash
+pytest
+```
+
+## License
+
+This project is licensed under the MIT License.

alembic.ini

@@ -0,0 +1,105 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = migrations
+
+# template used to generate migration file names; The default value is %%(rev)s_%%(slug)s
+# Uncomment the line below if you want the files to be prepended with date and time
+# see https://alembic.sqlalchemy.org/en/latest/tutorial.html#editing-the-ini-file
+# for all available tokens
+# file_template = %%(year)d_%%(month).2d_%%(day).2d_%%(hour).2d%%(minute).2d-%%(rev)s_%%(slug)s
+
+# sys.path path, will be prepended to sys.path if present.
+# defaults to the current working directory.
+prepend_sys_path = .
+
+# timezone to use when rendering the date within the migration file
+# as well as the filename.
+# If specified, requires the python-dateutil library that can be
+# installed by adding `alembic[tz]` to the pip requirements
+# string value is passed to dateutil.tz.gettz()
+# leave blank for localtime
+# timezone =
+
+# max length of characters to apply to the
+# "slug" field
+# truncate_slug_length = 40
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+# set to 'true' to allow .pyc and .pyo files without
+# a source .py file to be detected as revisions in the
+# versions/ directory
+# sourceless = false
+
+# version location specification; This defaults
+# to migrations/versions.  When using multiple version
+# directories, initial revisions must be specified with --version-path.
+# The path separator used here should be the separator specified by "version_path_separator" below.
+# version_locations = %(here)s/bar:%(here)s/bat:migrations/versions
+
+# version path separator; As mentioned above, this is the character used to split
+# version_locations. The default within new alembic.ini files is "os", which uses os.pathsep.
+# If this key is omitted entirely, it falls back to the legacy behavior of splitting on spaces and/or commas.
+# Valid values for version_path_separator are:
+#
+# version_path_separator = :
+# version_path_separator = ;
+# version_path_separator = space
+version_path_separator = os  # Use os.pathsep. Default configuration used for new projects.
+
+# the output encoding used when revision files
+# are written from script.py.mako
+# output_encoding = utf-8
+
+# SQLite URL
+sqlalchemy.url = sqlite:////app/storage/db/db.sqlite
+
+[post_write_hooks]
+# post_write_hooks defines scripts or Python functions that are run
+# on newly generated revision scripts.  See the documentation for further
+# detail and examples
+
+# format using "black" - use the console_scripts runner, against the "black" entrypoint
+# hooks = black
+# black.type = console_scripts
+# black.entrypoint = black
+# black.options = -l 79 REVISION_SCRIPT_FILENAME
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S

app/api/api.py

@@ -0,0 +1,7 @@
+from fastapi import APIRouter
+
+from app.api.endpoints import todos
+
+api_router = APIRouter()
+
+api_router.include_router(todos.router, prefix="/todos", tags=["todos"])

app/api/endpoints/todos.py

@@ -0,0 +1,76 @@
+from typing import List
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.db.session import get_db
+from app.models.todo import Todo
+from app.schemas.todo import TodoCreate, TodoResponse, TodoUpdate
+
+router = APIRouter()
+
+
+@router.post("", response_model=TodoResponse, status_code=status.HTTP_201_CREATED)
+def create_todo(todo_in: TodoCreate, db: Session = Depends(get_db)) -> TodoResponse:
+    """Create a new todo item."""
+    db_todo = Todo(
+        title=todo_in.title,
+        description=todo_in.description,
+        completed=todo_in.completed,
+    )
+    db.add(db_todo)
+    db.commit()
+    db.refresh(db_todo)
+    return db_todo
+
+
+@router.get("", response_model=List[TodoResponse])
+def read_todos(
+    skip: int = 0,
+    limit: int = 100,
+    db: Session = Depends(get_db),
+) -> List[TodoResponse]:
+    """Read all todo items with pagination."""
+    todos = db.query(Todo).offset(skip).limit(limit).all()
+    return todos
+
+
+@router.get("/{todo_id}", response_model=TodoResponse)
+def read_todo(todo_id: int, db: Session = Depends(get_db)) -> TodoResponse:
+    """Read a specific todo item by ID."""
+    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
+    if db_todo is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Todo not found")
+    return db_todo
+
+
+@router.put("/{todo_id}", response_model=TodoResponse)
+def update_todo(
+    todo_id: int,
+    todo_in: TodoUpdate,
+    db: Session = Depends(get_db),
+) -> TodoResponse:
+    """Update a todo item."""
+    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
+    if db_todo is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Todo not found")
+
+    update_data = todo_in.model_dump(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(db_todo, field, value)
+
+    db.commit()
+    db.refresh(db_todo)
+    return db_todo
+
+
+@router.delete("/{todo_id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
+def delete_todo(todo_id: int, db: Session = Depends(get_db)) -> None:
+    """Delete a todo item."""
+    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
+    if db_todo is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Todo not found")
+
+    db.delete(db_todo)
+    db.commit()
+    return None

app/core/config.py

@@ -0,0 +1,25 @@
+from pathlib import Path
+
+from pydantic_settings import BaseSettings
+
+
+class Settings(BaseSettings):
+    """Application settings."""
+
+    APP_NAME: str = "Simple Todo App"
+    APP_VERSION: str = "0.1.0"
+    DEBUG: bool = False
+
+    class Config:
+        env_file = ".env"
+        env_file_encoding = "utf-8"
+        case_sensitive = True
+
+
+settings = Settings()
+
+# Database setup
+DB_DIR = Path("/app") / "storage" / "db"
+DB_DIR.mkdir(parents=True, exist_ok=True)
+
+SQLALCHEMY_DATABASE_URL = f"sqlite:///{DB_DIR}/db.sqlite"

app/db/session.py

@@ -0,0 +1,28 @@
+from typing import Generator
+
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import Session, sessionmaker
+
+from app.core.config import SQLALCHEMY_DATABASE_URL
+
+# Create SQLAlchemy engine
+engine = create_engine(
+    SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False},  # Needed for SQLite
+)
+
+# Create session factory
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+# Create base class for models
+Base = declarative_base()
+
+
+def get_db() -> Generator[Session, None, None]:
+    """Dependency to get database session."""
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/__init__.py

@@ -0,0 +1 @@
+from app.models.todo import Todo  # noqa

app/models/todo.py

@@ -0,0 +1,21 @@
+from datetime import datetime
+
+from sqlalchemy import Boolean, Column, DateTime, Integer, String, Text
+
+from app.db.session import Base
+
+
+class Todo(Base):
+    """Todo model for database."""
+
+    __tablename__ = "todos"
+
+    id = Column(Integer, primary_key=True, index=True)
+    title = Column(String(100), nullable=False)
+    description = Column(Text, nullable=True)
+    completed = Column(Boolean, default=False)
+    created_at = Column(DateTime, default=datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+
+    def __repr__(self) -> str:
+        return f"<Todo id={self.id} title={self.title} completed={self.completed}>"

app/schemas/__init__.py

@@ -0,0 +1 @@
+from app.schemas.todo import TodoBase, TodoCreate, TodoUpdate, TodoInDB, TodoResponse  # noqa

app/schemas/todo.py

@@ -0,0 +1,43 @@
+from datetime import datetime
+from typing import Optional
+
+from pydantic import BaseModel, Field
+
+
+class TodoBase(BaseModel):
+    """Base schema for Todo."""
+
+    title: str = Field(..., min_length=1, max_length=100)
+    description: Optional[str] = None
+    completed: bool = False
+
+
+class TodoCreate(TodoBase):
+    """Schema for creating a Todo."""
+
+    pass
+
+
+class TodoUpdate(BaseModel):
+    """Schema for updating a Todo."""
+
+    title: Optional[str] = Field(None, min_length=1, max_length=100)
+    description: Optional[str] = None
+    completed: Optional[bool] = None
+
+
+class TodoInDB(TodoBase):
+    """Schema for Todo stored in DB."""
+
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+class TodoResponse(TodoInDB):
+    """Schema for Todo response."""
+
+    pass

main.py

@@ -0,0 +1,29 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.api import api_router
+from app.core.config import settings
+
+app = FastAPI(
+    title=settings.APP_NAME,
+    version=settings.APP_VERSION,
+    debug=settings.DEBUG,
+)
+
+# Configure CORS
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],  # Allows all origins
+    allow_credentials=True,
+    allow_methods=["*"],  # Allows all methods
+    allow_headers=["*"],  # Allows all headers
+)
+
+# Include API router
+app.include_router(api_router)
+
+
+@app.get("/health", tags=["Health"])
+async def health_check() -> dict[str, str]:
+    """Health check endpoint."""
+    return {"status": "ok"}

migrations/README

@@ -0,0 +1 @@
+Generic single-database configuration with SQLite.

migrations/env.py

@@ -0,0 +1,85 @@
+import os
+import sys
+from logging.config import fileConfig
+
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+
+# Add the parent directory to sys.path
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), "..")))
+
+# Import models
+from app.db.session import Base
+from app.models import Todo  # noqa
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+fileConfig(config.config_file_name)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+target_metadata = Base.metadata
+
+# other values from the config, defined by the needs of env.py,
+# can be acquired:
+# my_important_option = config.get_main_option("my_important_option")
+# ... etc.
+
+
+def run_migrations_offline():
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online():
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine
+    and associate a connection with the context.
+
+    """
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        is_sqlite = connection.dialect.name == "sqlite"
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata,
+            render_as_batch=is_sqlite,  # Required for SQLite
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

migrations/script.py.mako

@@ -0,0 +1,24 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision = ${repr(up_revision)}
+down_revision = ${repr(down_revision)}
+branch_labels = ${repr(branch_labels)}
+depends_on = ${repr(depends_on)}
+
+
+def upgrade():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

migrations/versions/001_create_todos_table.py

@@ -0,0 +1,40 @@
+"""create todos table
+
+Revision ID: 001
+Revises:
+Create Date: 2023-09-20
+
+"""
+
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = "001"
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.create_table(
+        "todos",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("title", sa.String(length=100), nullable=False),
+        sa.Column("description", sa.Text(), nullable=True),
+        sa.Column("completed", sa.Boolean(), default=False),
+        sa.Column("created_at", sa.DateTime(), default=sa.func.current_timestamp()),
+        sa.Column(
+            "updated_at",
+            sa.DateTime(),
+            default=sa.func.current_timestamp(),
+            onupdate=sa.func.current_timestamp(),
+        ),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(op.f("ix_todos_id"), "todos", ["id"], unique=False)
+
+
+def downgrade():
+    op.drop_index(op.f("ix_todos_id"), table_name="todos")
+    op.drop_table("todos")

pyproject.toml

@@ -0,0 +1,15 @@
+[tool.ruff]
+line-length = 100
+target-version = "py38"
+
+[tool.ruff.lint]
+select = ["E", "F", "B", "I", "N", "UP", "ANN", "S", "A", "COM"]
+ignore = ["ANN101", "ANN102", "S101", "B008", "ANN201", "ANN204"]
+
+[tool.ruff.lint.isort]
+known-first-party = ["app"]
+
+[tool.ruff.format]
+quote-style = "double"
+indent-style = "space"
+line-ending = "auto"

requirements.txt

@@ -0,0 +1,10 @@
+fastapi>=0.103.1
+uvicorn>=0.23.2
+sqlalchemy>=2.0.20
+alembic>=1.12.0
+pydantic>=2.3.0
+pydantic-settings>=2.0.3
+python-dotenv>=1.0.0
+ruff>=0.0.290
+pytest>=7.4.2
+httpx>=0.24.1

tests/test_api.py

@@ -0,0 +1,158 @@
+from fastapi.testclient import TestClient
+
+from app.db.session import Base, engine
+from main import app
+
+# Create test client
+client = TestClient(app)
+
+
+def test_health_check():
+    """Test health check endpoint."""
+    response = client.get("/health")
+    assert response.status_code == 200
+    assert response.json() == {"status": "ok"}
+
+
+def test_create_todo():
+    """Test creating a todo item."""
+    # Create test database tables
+    Base.metadata.create_all(bind=engine)
+
+    # Define test data
+    test_todo = {
+        "title": "Test Todo",
+        "description": "This is a test todo",
+        "completed": False,
+    }
+
+    # Send POST request
+    response = client.post("/todos", json=test_todo)
+
+    # Check response
+    assert response.status_code == 201
+    data = response.json()
+    assert data["title"] == test_todo["title"]
+    assert data["description"] == test_todo["description"]
+    assert data["completed"] == test_todo["completed"]
+    assert "id" in data
+    assert "created_at" in data
+    assert "updated_at" in data
+
+    # Cleanup test data
+    client.delete(f"/todos/{data['id']}")
+
+
+def test_read_todos():
+    """Test reading all todo items."""
+    # Create test database tables
+    Base.metadata.create_all(bind=engine)
+
+    # Create a test todo item
+    test_todo = {
+        "title": "Test Todo for Reading",
+        "description": "This is a test todo for reading",
+        "completed": False,
+    }
+    create_response = client.post("/todos", json=test_todo)
+    created_todo = create_response.json()
+
+    # Send GET request
+    response = client.get("/todos")
+
+    # Check response
+    assert response.status_code == 200
+    assert isinstance(response.json(), list)
+
+    # Cleanup test data
+    client.delete(f"/todos/{created_todo['id']}")
+
+
+def test_read_todo():
+    """Test reading a specific todo item."""
+    # Create test database tables
+    Base.metadata.create_all(bind=engine)
+
+    # Create a test todo item
+    test_todo = {
+        "title": "Test Todo for Reading One",
+        "description": "This is a test todo for reading one",
+        "completed": False,
+    }
+    create_response = client.post("/todos", json=test_todo)
+    created_todo = create_response.json()
+
+    # Send GET request
+    response = client.get(f"/todos/{created_todo['id']}")
+
+    # Check response
+    assert response.status_code == 200
+    data = response.json()
+    assert data["id"] == created_todo["id"]
+    assert data["title"] == test_todo["title"]
+    assert data["description"] == test_todo["description"]
+    assert data["completed"] == test_todo["completed"]
+
+    # Cleanup test data
+    client.delete(f"/todos/{created_todo['id']}")
+
+
+def test_update_todo():
+    """Test updating a todo item."""
+    # Create test database tables
+    Base.metadata.create_all(bind=engine)
+
+    # Create a test todo item
+    test_todo = {
+        "title": "Test Todo for Updating",
+        "description": "This is a test todo for updating",
+        "completed": False,
+    }
+    create_response = client.post("/todos", json=test_todo)
+    created_todo = create_response.json()
+
+    # Define update data
+    update_data = {
+        "title": "Updated Test Todo",
+        "completed": True,
+    }
+
+    # Send PUT request
+    response = client.put(f"/todos/{created_todo['id']}", json=update_data)
+
+    # Check response
+    assert response.status_code == 200
+    data = response.json()
+    assert data["id"] == created_todo["id"]
+    assert data["title"] == update_data["title"]
+    assert data["description"] == test_todo["description"]  # Should remain unchanged
+    assert data["completed"] == update_data["completed"]
+
+    # Cleanup test data
+    client.delete(f"/todos/{created_todo['id']}")
+
+
+def test_delete_todo():
+    """Test deleting a todo item."""
+    # Create test database tables
+    Base.metadata.create_all(bind=engine)
+
+    # Create a test todo item
+    test_todo = {
+        "title": "Test Todo for Deleting",
+        "description": "This is a test todo for deleting",
+        "completed": False,
+    }
+    create_response = client.post("/todos", json=test_todo)
+    created_todo = create_response.json()
+
+    # Send DELETE request
+    response = client.delete(f"/todos/{created_todo['id']}")
+
+    # Check response
+    assert response.status_code == 204
+    assert response.content == b""  # No content should be returned
+
+    # Verify the todo is deleted
+    get_response = client.get(f"/todos/{created_todo['id']}")
+    assert get_response.status_code == 404