Create simple Todo app with FastAPI and SQLite

README.md

@@ -1,3 +1,106 @@
-# FastAPI Application
+# Simple Todo App
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+This is a simple Todo application API built with FastAPI and SQLite. It allows you to create, read, update, and delete todo items through a RESTful API.
+
+## Features
+
+- RESTful API for Todo items
+- SQLite database for persistence
+- Alembic migrations for database versioning
+- Data validation with Pydantic
+- Health check endpoint
+- API documentation with Swagger UI
+
+## Project Structure
+
+```
+.
+├── app/                    # Application package
+│   ├── api/                # API endpoints
+│   │   ├── health.py       # Health check endpoint
+│   │   └── todos.py        # Todo CRUD endpoints
+│   ├── database/           # Database configuration
+│   │   └── database.py     # SQLAlchemy setup
+│   ├── models/             # SQLAlchemy models
+│   │   └── todo.py         # Todo model
+│   └── schemas/            # Pydantic schemas
+│       └── todo.py         # Todo schemas for validation
+├── migrations/             # Alembic migrations
+│   └── versions/           # Migration scripts
+│       └── 001_create_todos_table.py # Initial migration
+├── alembic.ini             # Alembic configuration
+├── main.py                 # FastAPI application entry point
+└── requirements.txt        # Project dependencies
+```
+
+## Requirements
+
+- Python 3.8 or higher
+
+## Installation
+
+1. Clone the repository:
+
+```bash
+git clone <repository-url>
+cd <repository-directory>
+```
+
+2. Install dependencies:
+
+```bash
+pip install -r requirements.txt
+```
+
+## Running the Application
+
+To run the application in development mode:
+
+```bash
+uvicorn main:app --reload
+```
+
+The application will be available at http://localhost:8000.
+
+## API Documentation
+
+- Swagger UI documentation: http://localhost:8000/docs
+- ReDoc documentation: http://localhost:8000/redoc
+
+## API Endpoints
+
+### Health Check
+
+- `GET /health` - Check if the application is running properly
+
+### Todo Items
+
+- `GET /api/v1/todos` - List all todo items
+- `POST /api/v1/todos` - Create a new todo item
+- `GET /api/v1/todos/{todo_id}` - Get a specific todo item
+- `PUT /api/v1/todos/{todo_id}` - Update a todo item
+- `DELETE /api/v1/todos/{todo_id}` - Delete a todo item
+
+## Database Migrations
+
+The application uses Alembic for database migrations. The initial migration to create the todos table is already included.
+
+To apply migrations:
+
+```bash
+alembic upgrade head
+```
+
+## Development
+
+This project uses Ruff for linting. To run the linter:
+
+```bash
+ruff check .
+```
+
+To automatically fix issues:
+
+```bash
+ruff check --fix .
+```

alembic.ini

@@ -0,0 +1,109 @@
+# 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.
+
+# set to 'true' to search source files recursively
+# in each "version_locations" directory
+# new in Alembic version 1.10
+# recursive_version_locations = false
+
+# the output encoding used when revision files
+# are written from script.py.mako
+# output_encoding = utf-8
+
+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/health.py

@@ -0,0 +1,25 @@
+from fastapi import APIRouter, Depends
+from sqlalchemy.orm import Session
+from sqlalchemy import text
+
+from app.database.database import get_db
+
+router = APIRouter()
+
+@router.get("/health")
+def health_check(db: Session = Depends(get_db)):
+    """
+    Health check endpoint that verifies the application is running
+    and able to connect to the database
+    """
+    # Test database connection
+    try:
+        db.execute(text("SELECT 1"))
+        db_status = "healthy"
+    except Exception as e:
+        db_status = f"unhealthy: {str(e)}"
+    
+    return {
+        "status": "ok",
+        "database": db_status
+    }

app/api/todos.py

@@ -0,0 +1,58 @@
+from typing import List
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.database.database import get_db
+from app.models.todo import Todo
+from app.schemas.todo import TodoCreate, TodoResponse, TodoUpdate
+
+router = APIRouter()
+
+@router.post("/todos", response_model=TodoResponse, status_code=status.HTTP_201_CREATED)
+def create_todo(todo: TodoCreate, db: Session = Depends(get_db)):
+    """Create a new todo item"""
+    db_todo = Todo(**todo.model_dump())
+    db.add(db_todo)
+    db.commit()
+    db.refresh(db_todo)
+    return db_todo
+
+@router.get("/todos", response_model=List[TodoResponse])
+def read_todos(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
+    """Get all todo items"""
+    todos = db.query(Todo).offset(skip).limit(limit).all()
+    return todos
+
+@router.get("/todos/{todo_id}", response_model=TodoResponse)
+def read_todo(todo_id: int, db: Session = Depends(get_db)):
+    """Get 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=404, detail="Todo not found")
+    return db_todo
+
+@router.put("/todos/{todo_id}", response_model=TodoResponse)
+def update_todo(todo_id: int, todo: TodoUpdate, db: Session = Depends(get_db)):
+    """Update a todo item"""
+    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    
+    update_data = todo.model_dump(exclude_unset=True)
+    for key, value in update_data.items():
+        setattr(db_todo, key, value)
+    
+    db.commit()
+    db.refresh(db_todo)
+    return db_todo
+
+@router.delete("/todos/{todo_id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
+def delete_todo(todo_id: int, db: Session = Depends(get_db)):
+    """Delete a todo item"""
+    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    
+    db.delete(db_todo)
+    db.commit()
+    return None

app/database/database.py

@@ -0,0 +1,35 @@
+from pathlib import Path
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+
+# Create database directory if it doesn't exist
+DB_DIR = Path("/app") / "storage" / "db"
+DB_DIR.mkdir(parents=True, exist_ok=True)
+
+# Database URL for SQLite
+SQLALCHEMY_DATABASE_URL = f"sqlite:///{DB_DIR}/db.sqlite"
+
+# Create SQLAlchemy engine
+engine = create_engine(
+    SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False}
+)
+
+# Create sessionmaker
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+# Create base class for models
+Base = declarative_base()
+
+# Dependency to get DB session
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+# Function to create tables
+def create_tables():
+    Base.metadata.create_all(bind=engine)

app/models/todo.py

@@ -0,0 +1,13 @@
+import datetime
+from sqlalchemy import Column, Integer, String, Boolean, DateTime
+from app.database.database import Base
+
+class Todo(Base):
+    __tablename__ = "todos"
+
+    id = Column(Integer, primary_key=True, index=True)
+    title = Column(String, index=True)
+    description = Column(String, nullable=True)
+    completed = Column(Boolean, default=False)
+    created_at = Column(DateTime, default=datetime.datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.datetime.utcnow, onupdate=datetime.datetime.utcnow)

app/schemas/todo.py

@@ -0,0 +1,24 @@
+from datetime import datetime
+from typing import Optional
+from pydantic import BaseModel, Field
+
+class TodoBase(BaseModel):
+    title: str = Field(..., min_length=1, max_length=100)
+    description: Optional[str] = Field(None, max_length=500)
+    completed: bool = False
+
+class TodoCreate(TodoBase):
+    pass
+
+class TodoUpdate(BaseModel):
+    title: Optional[str] = Field(None, min_length=1, max_length=100)
+    description: Optional[str] = Field(None, max_length=500)
+    completed: Optional[bool] = None
+
+class TodoResponse(TodoBase):
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True

main.py

@@ -0,0 +1,32 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+from app.api import todos, health
+from app.database.database import create_tables
+
+app = FastAPI(
+    title="Todo App API",
+    description="A simple Todo app API built with FastAPI",
+    version="0.1.0",
+)
+
+# Add CORS middleware
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],  # For production, restrict this to specific domains
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Create database tables when app starts
+@app.on_event("startup")
+async def startup_event():
+    create_tables()
+
+# Include routers
+app.include_router(todos.router, prefix="/api/v1", tags=["todos"])
+app.include_router(health.router, tags=["health"])
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

migrations/env.py

@@ -0,0 +1,76 @@
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+from app.models.todo import Todo  # noqa
+from app.database.database import Base
+
+# 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.
+if config.config_file_name is not None:
+    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() -> None:
+    """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() -> None:
+    """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:
+        # For SQLite, use batch mode
+        is_sqlite = connection.dialect.name == 'sqlite'
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata,
+            render_as_batch=is_sqlite,  # Key configuration for SQLite
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()

migrations/script.py.mako

@@ -0,0 +1,26 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision: str = ${repr(up_revision)}
+down_revision: Union[str, None] = ${repr(down_revision)}
+branch_labels: Union[str, Sequence[str], None] = ${repr(branch_labels)}
+depends_on: Union[str, Sequence[str], None] = ${repr(depends_on)}
+
+
+def upgrade() -> None:
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    ${downgrades if downgrades else "pass"}

migrations/versions/001_create_todos_table.py

@@ -0,0 +1,42 @@
+"""Create todos table
+
+Revision ID: 001
+Revises: 
+Create Date: 2023-12-18
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = '001'
+down_revision: Union[str, None] = None
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # Create todos table
+    op.create_table(
+        'todos',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('title', sa.String(), nullable=False),
+        sa.Column('description', sa.String(), 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')
+    )
+    # Create index on title
+    op.create_index(op.f('ix_todos_id'), 'todos', ['id'], unique=False)
+    op.create_index(op.f('ix_todos_title'), 'todos', ['title'], unique=False)
+
+
+def downgrade() -> None:
+    # Drop todos table
+    op.drop_index(op.f('ix_todos_title'), table_name='todos')
+    op.drop_index(op.f('ix_todos_id'), table_name='todos')
+    op.drop_table('todos')

requirements.txt

@@ -0,0 +1,7 @@
+fastapi>=0.105.0
+uvicorn>=0.25.0
+sqlalchemy>=2.0.0
+pydantic>=2.5.0
+alembic>=1.13.0
+python-dotenv>=1.0.0
+ruff>=0.1.6