Create Todo Application with FastAPI and SQLite

- Set up project structure with FastAPI
- Create Todo database model with SQLAlchemy
- Add Alembic migrations
- Implement CRUD API endpoints for todos
- Add health endpoint for application monitoring
- Add README with documentation

generated with BackendIM... (backend.im)

README.md

@@ -1,3 +1,62 @@
-# FastAPI Application
+# Todo Application API
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+This is a RESTful API for managing todo items built with FastAPI and SQLite.
+
+## Features
+
+- Create, read, update, and delete todo items
+- SQLAlchemy ORM for database interactions
+- Alembic migrations for database versioning
+- Health endpoint for monitoring
+- API documentation with Swagger UI and ReDoc
+
+## Project Structure
+
+```
+todo-application/
+├── app/
+│   ├── api/                 # API endpoints
+│   │   └── v1/              # API version 1
+│   ├── core/                # Core configuration
+│   ├── db/                  # Database setup and sessions
+│   ├── models/              # SQLAlchemy models
+│   └── schemas/             # Pydantic schemas
+├── migrations/              # Alembic migrations
+├── alembic.ini              # Alembic configuration
+├── main.py                  # Application entry point
+└── requirements.txt         # Dependencies
+```
+
+## API Endpoints
+
+- `GET /api/v1/todos`: List all todos
+- `POST /api/v1/todos`: Create a new todo
+- `GET /api/v1/todos/{todo_id}`: Get a specific todo
+- `PUT /api/v1/todos/{todo_id}`: Update a specific todo
+- `DELETE /api/v1/todos/{todo_id}`: Delete a specific todo
+- `GET /health`: Health check endpoint
+
+## Documentation
+
+API documentation is available at:
+- Swagger UI: `/docs`
+- ReDoc: `/redoc`
+
+## Running the Application
+
+```bash
+uvicorn main:app --reload
+```
+
+The application will be available at http://localhost:8000.
+
+## Development
+
+### Requirements
+
+- Python 3.8+
+- FastAPI
+- SQLAlchemy
+- Alembic
+- Uvicorn
+- Ruff (for linting)

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
+
+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/v1/api.py

@@ -0,0 +1,6 @@
+from fastapi import APIRouter
+
+from app.api.v1.endpoints import todos
+
+api_router = APIRouter()
+api_router.include_router(todos.router, prefix="/todos", tags=["todos"])

app/api/v1/endpoints/todos.py

@@ -0,0 +1,94 @@
+from typing import List, Any, Optional
+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, TodoUpdate, Todo as TodoSchema
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[TodoSchema])
+def read_todos(
+    skip: int = 0, limit: int = 100, db: Session = Depends(get_db)
+) -> Any:
+    """
+    Retrieve todos.
+    """
+    todos = db.query(Todo).offset(skip).limit(limit).all()
+    return todos
+
+
+@router.post("/", response_model=TodoSchema, status_code=status.HTTP_201_CREATED)
+def create_todo(*, db: Session = Depends(get_db), todo_in: TodoCreate) -> Any:
+    """
+    Create new todo.
+    """
+    todo = Todo(
+        title=todo_in.title,
+        description=todo_in.description,
+        completed=todo_in.completed
+    )
+    db.add(todo)
+    db.commit()
+    db.refresh(todo)
+    return todo
+
+
+@router.get("/{todo_id}", response_model=TodoSchema)
+def read_todo(*, db: Session = Depends(get_db), todo_id: int) -> Any:
+    """
+    Get todo by ID.
+    """
+    todo = db.query(Todo).filter(Todo.id == todo_id).first()
+    if not todo:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Todo not found"
+        )
+    return todo
+
+
+@router.put("/{todo_id}", response_model=TodoSchema)
+def update_todo(
+    *,
+    db: Session = Depends(get_db),
+    todo_id: int,
+    todo_in: TodoUpdate,
+) -> Any:
+    """
+    Update a todo.
+    """
+    todo = db.query(Todo).filter(Todo.id == todo_id).first()
+    if not todo:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Todo not found"
+        )
+    
+    update_data = todo_in.dict(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(todo, field, value)
+    
+    db.add(todo)
+    db.commit()
+    db.refresh(todo)
+    return todo
+
+
+@router.delete("/{todo_id}", status_code=status.HTTP_204_NO_CONTENT)
+def delete_todo(*, db: Session = Depends(get_db), todo_id: int) -> Any:
+    """
+    Delete a todo.
+    """
+    todo = db.query(Todo).filter(Todo.id == todo_id).first()
+    if not todo:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Todo not found"
+        )
+    
+    db.delete(todo)
+    db.commit()
+    return None

app/core/config.py

@@ -0,0 +1,16 @@
+from pydantic_settings import BaseSettings
+from pathlib import Path
+
+
+class Settings(BaseSettings):
+    PROJECT_NAME: str = "Todo Application"
+    VERSION: str = "0.1.0"
+    API_V1_STR: str = "/api/v1"
+
+    # Database
+    DB_DIR = Path("/app") / "storage" / "db"
+    DB_DIR.mkdir(parents=True, exist_ok=True)
+    SQLALCHEMY_DATABASE_URL: str = f"sqlite:///{DB_DIR}/db.sqlite"
+
+
+settings = Settings()

app/db/session.py

@@ -0,0 +1,32 @@
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+from pathlib import Path
+
+from app.core.config import settings
+
+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()
+
+
+def create_db_and_tables():
+    Base.metadata.create_all(bind=engine)
+
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/todo.py

@@ -0,0 +1,14 @@
+from sqlalchemy import Column, Integer, String, Boolean, DateTime, func
+from sqlalchemy.ext.declarative import declarative_base
+from app.db.session 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=func.now())
+    updated_at = Column(DateTime, default=func.now(), onupdate=func.now())

app/schemas/todo.py

@@ -0,0 +1,32 @@
+from pydantic import BaseModel
+from datetime import datetime
+from typing import Optional
+
+
+class TodoBase(BaseModel):
+    title: str
+    description: Optional[str] = None
+    completed: bool = False
+
+
+class TodoCreate(TodoBase):
+    pass
+
+
+class TodoUpdate(BaseModel):
+    title: Optional[str] = None
+    description: Optional[str] = None
+    completed: Optional[bool] = None
+
+
+class TodoInDBBase(TodoBase):
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        orm_mode = True
+
+
+class Todo(TodoInDBBase):
+    pass

main.py

@@ -0,0 +1,33 @@
+from fastapi import FastAPI
+from pathlib import Path
+
+from app.api.v1.api import api_router
+from app.core.config import settings
+from app.db.session import create_db_and_tables
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    openapi_url=f"{settings.API_V1_STR}/openapi.json",
+)
+
+app.include_router(api_router, prefix=settings.API_V1_STR)
+
+
+@app.get("/health", tags=["health"])
+async def health():
+    return {
+        "status": "ok",
+        "name": settings.PROJECT_NAME,
+        "version": settings.VERSION,
+    }
+
+
+@app.on_event("startup")
+def on_startup():
+    create_db_and_tables()
+
+
+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 an async dbapi.

migrations/env.py

@@ -0,0 +1,92 @@
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+
+import os, sys
+from pathlib import Path
+
+# Add the parent directory to sys.path
+sys.path.insert(0, str(Path(__file__).parent.parent))
+
+# Import all models for Alembic to detect
+from app.models.todo import Todo
+from app.db.session import Base
+from app.core.config import settings
+
+# 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)
+
+# Set SQLAlchemy URL from settings
+config.set_main_option("sqlalchemy.url", settings.SQLALCHEMY_DATABASE_URL)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+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:
+        context.configure(
+            connection=connection, target_metadata=target_metadata
+        )
+
+        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 +1,40 @@
+"""Initial migration
+
+Revision ID: 001
+Revises: 
+Create Date: 2025-05-14
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '001'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    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, nullable=False),
+        sa.Column('created_at', sa.DateTime(), default=sa.func.now(), nullable=False),
+        sa.Column('updated_at', sa.DateTime(), default=sa.func.now(), nullable=False),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_todos_id'), 'todos', ['id'], unique=False)
+    op.create_index(op.f('ix_todos_title'), 'todos', ['title'], unique=False)
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    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')
+    # ### end Alembic commands ###

requirements.txt

@@ -0,0 +1,7 @@
+fastapi==0.104.1
+uvicorn==0.23.2
+sqlalchemy==2.0.22
+alembic==1.12.1
+pydantic==2.4.2
+pydantic-settings==2.0.3
+ruff==0.1.3