Add simple todo app with FastAPI and SQLite

- Created FastAPI application with CRUD endpoints for todos
- Set up SQLAlchemy with SQLite database
- Created database models and Pydantic schemas
- Added Alembic for database migrations
- Added health check endpoint
- Updated README with project information

generated with BackendIM... (backend.im)

README.md

@@ -1,3 +1,73 @@
-# FastAPI Application
+# Simple Todo App
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+This is a simple Todo API built with FastAPI and SQLite.
+
+## Features
+
+- Create, read, update, and delete todo items
+- Health check endpoint
+- SQLite database with SQLAlchemy ORM
+- Alembic for database migrations
+
+## Project Structure
+
+```
+simpletodoapp/
+│
+├── alembic/                      # Database migrations
+│   ├── versions/                 # Migration versions
+│   ├── env.py                    # Alembic environment configuration
+│   └── script.py.mako            # Migration script template
+│
+├── app/                          # Application package
+│   ├── __init__.py
+│   ├── crud.py                   # CRUD operations
+│   ├── database.py               # Database setup and connection
+│   ├── models.py                 # SQLAlchemy models
+│   └── schemas.py                # Pydantic schemas for API
+│
+├── alembic.ini                   # Alembic configuration
+├── main.py                       # FastAPI application and endpoints
+└── requirements.txt              # Python dependencies
+```
+
+## API Endpoints
+
+- `GET /health` - Health check endpoint
+- `GET /todos` - Get all todos
+- `POST /todos` - Create a new todo
+- `GET /todos/{todo_id}` - Get a specific todo
+- `PUT /todos/{todo_id}` - Update a todo
+- `DELETE /todos/{todo_id}` - Delete a todo
+
+## Getting Started
+
+1. Install dependencies:
+   ```
+   pip install -r requirements.txt
+   ```
+
+2. Run database migrations:
+   ```
+   alembic upgrade head
+   ```
+
+3. Start the application:
+   ```
+   uvicorn main:app --reload
+   ```
+
+4. Access the API documentation at http://localhost:8000/docs
+
+## Todo Item Schema
+
+```json
+{
+  "id": 1,
+  "title": "Task title",
+  "description": "Task description",
+  "completed": false,
+  "created_at": "2023-01-01T00:00:00",
+  "updated_at": "2023-01-01T00:00:00"
+}
+```

alembic.ini

@@ -0,0 +1,107 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = alembic
+
+# template used to generate migration files
+# file_template = %%(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>=3.9
+# from time import has_tzinfo will be used to determine the
+# migration filename.
+# If set to 'true', alembic will use the system timezone.
+# 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 alembic/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:alembic/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

alembic/env.py

@@ -0,0 +1,77 @@
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+
+# 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
+from app.database import Base
+from app.models import Todo
+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:
+        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()

alembic/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"}

alembic/versions/e55826737163_create_todos_table.py

@@ -0,0 +1,36 @@
+"""Create todos table
+
+Revision ID: e55826737163
+Revises: 
+Create Date: 2023-01-01 00:00:00.000000
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'e55826737163'
+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(), nullable=False),
+        sa.Column('description', sa.String(), nullable=True),
+        sa.Column('completed', sa.Boolean(), nullable=True, default=False),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)')),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)')),
+        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)
+
+
+def downgrade():
+    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')

app/__init__.py

@@ -0,0 +1 @@
+# App package initialization

app/crud.py

@@ -0,0 +1,40 @@
+from sqlalchemy.orm import Session
+from . import models, schemas
+
+def get_todo(db: Session, todo_id: int):
+    return db.query(models.Todo).filter(models.Todo.id == todo_id).first()
+
+def get_todos(db: Session, skip: int = 0, limit: int = 100):
+    return db.query(models.Todo).offset(skip).limit(limit).all()
+
+def create_todo(db: Session, todo: schemas.TodoCreate):
+    db_todo = models.Todo(
+        title=todo.title,
+        description=todo.description,
+        completed=todo.completed
+    )
+    db.add(db_todo)
+    db.commit()
+    db.refresh(db_todo)
+    return db_todo
+
+def update_todo(db: Session, todo_id: int, todo: schemas.TodoUpdate):
+    db_todo = get_todo(db, todo_id)
+    
+    # Update fields if they are 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
+
+def delete_todo(db: Session, todo_id: int):
+    db_todo = get_todo(db, todo_id)
+    db.delete(db_todo)
+    db.commit()
+    return db_todo

app/database.py

@@ -0,0 +1,26 @@
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+from pathlib import Path
+
+# Create database directory
+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 get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models.py

@@ -0,0 +1,13 @@
+from sqlalchemy import Boolean, Column, Integer, String, DateTime
+from sqlalchemy.sql import func
+from .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(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())

app/schemas.py

@@ -0,0 +1,24 @@
+from pydantic import BaseModel
+from typing import Optional
+from datetime import datetime
+
+class TodoBase(BaseModel):
+    title: str
+    description: Optional[str] = None
+    completed: Optional[bool] = False
+
+class TodoCreate(TodoBase):
+    pass
+
+class TodoUpdate(BaseModel):
+    title: Optional[str] = None
+    description: Optional[str] = None
+    completed: Optional[bool] = None
+
+class Todo(TodoBase):
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        orm_mode = True

main.py

@@ -0,0 +1,70 @@
+from fastapi import FastAPI, Depends, HTTPException
+from fastapi.middleware.cors import CORSMiddleware
+import uvicorn
+from typing import List
+from pathlib import Path
+
+from app.database import engine, get_db
+from app import models, schemas, crud
+from sqlalchemy.orm import Session
+
+# Create the database tables
+models.Base.metadata.create_all(bind=engine)
+
+app = FastAPI(
+    title="Todo API",
+    description="A simple Todo API built with FastAPI and SQLite",
+    version="1.0.0"
+)
+
+# CORS middleware
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+@app.get("/health", tags=["Health"])
+async def health_check():
+    """Health check endpoint"""
+    return {"status": "healthy"}
+
+@app.get("/todos", response_model=List[schemas.Todo], tags=["Todos"])
+def read_todos(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
+    """Get all todos"""
+    todos = crud.get_todos(db, skip=skip, limit=limit)
+    return todos
+
+@app.post("/todos", response_model=schemas.Todo, status_code=201, tags=["Todos"])
+def create_todo(todo: schemas.TodoCreate, db: Session = Depends(get_db)):
+    """Create a new todo"""
+    return crud.create_todo(db=db, todo=todo)
+
+@app.get("/todos/{todo_id}", response_model=schemas.Todo, tags=["Todos"])
+def read_todo(todo_id: int, db: Session = Depends(get_db)):
+    """Get a specific todo by id"""
+    db_todo = crud.get_todo(db, todo_id=todo_id)
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    return db_todo
+
+@app.put("/todos/{todo_id}", response_model=schemas.Todo, tags=["Todos"])
+def update_todo(todo_id: int, todo: schemas.TodoUpdate, db: Session = Depends(get_db)):
+    """Update a todo"""
+    db_todo = crud.get_todo(db, todo_id=todo_id)
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    return crud.update_todo(db=db, todo_id=todo_id, todo=todo)
+
+@app.delete("/todos/{todo_id}", response_model=schemas.Todo, tags=["Todos"])
+def delete_todo(todo_id: int, db: Session = Depends(get_db)):
+    """Delete a todo"""
+    db_todo = crud.get_todo(db, todo_id=todo_id)
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    return crud.delete_todo(db=db, todo_id=todo_id)
+
+if __name__ == "__main__":
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

requirements.txt

@@ -0,0 +1,6 @@
+fastapi>=0.68.0
+uvicorn>=0.15.0
+sqlalchemy>=1.4.23
+alembic>=1.7.3
+pydantic>=1.8.2
+python-dotenv>=0.19.0