Create simple Todo app with FastAPI and SQLite

README.md

@@ -1,3 +1,78 @@
-# FastAPI Application
+# Simple Todo App
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A RESTful API for managing todo items, built with FastAPI and SQLite.
+
+## Features
+
+- Create, read, update, and delete todo items
+- SQLite database with SQLAlchemy ORM
+- Alembic for database migrations
+- Health check endpoint
+- API documentation with Swagger UI
+
+## Prerequisites
+
+- Python 3.9+
+- Pip package manager
+
+## Project Structure
+
+```
+simpletodoapp/
+├── app/
+│   ├── database/      # Database connection and session management
+│   ├── models/        # SQLAlchemy ORM models
+│   ├── routers/       # FastAPI route definitions
+│   └── schemas/       # Pydantic schemas for request/response validation
+├── migrations/        # Alembic migrations
+├── alembic.ini        # Alembic configuration
+├── main.py            # Application entry point
+├── pyproject.toml     # Project configuration
+└── requirements.txt   # Project dependencies
+```
+
+## Installation
+
+1. Clone the repository:
+```bash
+git clone <repository-url>
+cd simpletodoapp
+```
+
+2. Install the dependencies:
+```bash
+pip install -r requirements.txt
+```
+
+## Running the Application
+
+Start the application with Uvicorn:
+
+```bash
+uvicorn main:app --reload
+```
+
+The API will be available at `http://localhost:8000`.
+
+## API Documentation
+
+Once the application is running, you can access the interactive API documentation:
+
+- Swagger UI: `http://localhost:8000/docs`
+- ReDoc: `http://localhost:8000/redoc`
+
+## API Endpoints
+
+### Health Check
+- `GET /health` - Check the health of the service
+
+### Todo Operations
+- `POST /api/todos` - Create a new todo item
+- `GET /api/todos` - Get all todo items
+- `GET /api/todos/{todo_id}` - Get a specific todo item
+- `PUT /api/todos/{todo_id}` - Update a todo item
+- `DELETE /api/todos/{todo_id}` - Delete a todo item
+
+## License
+
+MIT

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/database/__init__.py

@@ -0,0 +1,3 @@
+from .database import Base, engine, get_db
+
+__all__ = ["Base", "engine", "get_db"]

app/database/database.py

@@ -0,0 +1,28 @@
+from pathlib import Path
+
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+
+# Create DB directory if it doesn't exist
+DB_DIR = Path("/app") / "storage" / "db"
+DB_DIR.mkdir(parents=True, exist_ok=True)
+
+SQLALCHEMY_DATABASE_URL = f"sqlite:///{DB_DIR}/db.sqlite"
+
+engine = create_engine(
+    SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False}
+)
+
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+Base = declarative_base()
+
+# Dependency to get DB session
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/__init__.py

@@ -0,0 +1,3 @@
+from .todo import Todo
+
+__all__ = ["Todo"]

app/models/todo.py

@@ -0,0 +1,18 @@
+from sqlalchemy import Boolean, Column, DateTime, Integer, String
+from sqlalchemy.sql import func
+
+from app.database.database import Base
+
+
+class Todo(Base):
+    """
+    SQLAlchemy model for Todo items
+    """
+    __tablename__ = "todos"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    title = Column(String, nullable=False)
+    description = Column(String, nullable=True)
+    completed = Column(Boolean, default=False)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())

app/routers/health.py

@@ -0,0 +1,30 @@
+from fastapi import APIRouter, Depends
+from sqlalchemy.orm import Session
+
+from app.database import get_db
+
+router = APIRouter()
+
+@router.get("/health", summary="Check service health")
+def health(db: Session = Depends(get_db)):
+    """
+    Checks the health of the service.
+    
+    Returns:
+        dict: A dictionary with the status of the service components
+    """
+    # Check database connection
+    try:
+        # Execute a simple query to verify database connection
+        db.execute("SELECT 1")
+        db_status = "healthy"
+    except Exception as e:
+        db_status = f"unhealthy: {str(e)}"
+    
+    return {
+        "status": "ok",
+        "components": {
+            "api": "healthy",
+            "database": db_status
+        }
+    }

app/routers/todos.py

@@ -0,0 +1,81 @@
+from typing import List
+
+from fastapi import APIRouter, Depends, HTTPException, Response, status
+from sqlalchemy.orm import Session
+
+from app.database 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: TodoCreate, db: Session = Depends(get_db)):
+    """
+    Create a new todo item
+    """
+    db_todo = Todo(
+        title=todo.title,
+        description=todo.description,
+        completed=todo.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)):
+    """
+    Retrieve 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)):
+    """
+    Retrieve 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("/{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 todo fields if provided
+    if todo.title is not None:
+        db_todo.title = todo.title
+    if todo.description is not None:
+        db_todo.description = todo.description
+    if todo.completed is not None:
+        db_todo.completed = todo.completed
+    
+    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)):
+    """
+    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 Response(status_code=status.HTTP_204_NO_CONTENT)

app/schemas/__init__.py

@@ -0,0 +1,3 @@
+from .todo import TodoBase, TodoCreate, TodoResponse, TodoUpdate
+
+__all__ = ["TodoBase", "TodoCreate", "TodoUpdate", "TodoResponse"]

app/schemas/todo.py

@@ -0,0 +1,38 @@
+from datetime import datetime
+from typing import Optional
+
+from pydantic import BaseModel, Field
+
+
+class TodoBase(BaseModel):
+    """
+    Base schema for Todo items
+    """
+    title: str = Field(..., min_length=1, max_length=100)
+    description: Optional[str] = Field(None, max_length=500)
+    completed: bool = False
+
+class TodoCreate(TodoBase):
+    """
+    Schema for creating a new Todo item
+    """
+    pass
+
+class TodoUpdate(BaseModel):
+    """
+    Schema for updating a Todo item
+    """
+    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):
+    """
+    Schema for Todo response that includes database fields
+    """
+    id: int
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+    
+    class Config:
+        from_attributes = True

main.py

@@ -0,0 +1,22 @@
+
+from fastapi import FastAPI
+
+from app.database import Base, engine
+from app.routers import health, todos
+
+# Create tables
+Base.metadata.create_all(bind=engine)
+
+app = FastAPI(
+    title="SimpleTodoApp",
+    description="A simple Todo application with FastAPI",
+    version="0.1.0"
+)
+
+# Include routers
+app.include_router(todos.router, tags=["todos"], prefix="/api/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/README

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

migrations/env.py

@@ -0,0 +1,86 @@
+# isort: skip_file
+# ruff: noqa: E402
+from logging.config import fileConfig
+
+from alembic import context
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+# Import Base and models
+from app.database.database import Base
+# Need to import Todo to ensure it's registered with the metadata
+import app.models.todo  # noqa: F401
+
+# 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:
+        is_sqlite = connection.dialect.name == 'sqlite'
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata,
+            render_as_batch=is_sqlite,  # Key configuration for SQLite
+            compare_type=True
+        )
+
+        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() -> None:
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    ${downgrades if downgrades else "pass"}

migrations/versions/initial_migration.py

@@ -0,0 +1,43 @@
+"""Initial migration
+# isort: skip_file
+# ruff: noqa: I001
+
+Revision ID: a1b2c3d4e5f6
+Revises: 
+Create Date: 2023-10-11 12:00:00.000000
+
+"""
+from alembic import op  # noqa: I001
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'a1b2c3d4e5f6'
+down_revision = None
+branch_labels = None
+depends_on = 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(), nullable=True),
+        sa.Column(
+            'created_at', 
+            sa.DateTime(timezone=True), 
+            server_default=sa.text('(CURRENT_TIMESTAMP)'), 
+            nullable=True
+        ),
+        sa.Column('updated_at', sa.DateTime(timezone=True), nullable=True),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_todos_id'), 'todos', ['id'], unique=False)
+
+
+def downgrade() -> None:
+    # Drop todos table
+    op.drop_index(op.f('ix_todos_id'), table_name='todos')
+    op.drop_table('todos')

pyproject.toml

@@ -0,0 +1,31 @@
+[tool.ruff]
+# Enable linting rules
+line-length = 88
+target-version = "py39"
+
+[tool.ruff.lint]
+select = ["E", "F", "B", "I"]
+
+# Exclude a variety of commonly ignored directories.
+exclude = [
+    ".git",
+    ".mypy_cache",
+    ".ruff_cache",
+    ".venv",
+    "__pypackages__",
+    "migrations",
+    "dist",
+]
+
+# Allow unused variables when underscore-prefixed.
+dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"
+
+# Ignore some errors for endpoint dependency injection
+ignore = ["B008"] # Allow Depends() function call in parameters
+
+[tool.ruff.lint.mccabe]
+# Unlike Flake8, default to a complexity level of 10.
+max-complexity = 10
+
+[tool.ruff.lint.isort]
+known-third-party = ["fastapi", "pydantic", "sqlalchemy", "alembic"]

requirements.txt

@@ -0,0 +1,7 @@
+fastapi>=0.104.0
+uvicorn>=0.23.2
+sqlalchemy>=2.0.22
+alembic>=1.12.0
+pydantic>=2.4.2
+python-dotenv>=1.0.0
+ruff>=0.1.3