Create simple inventory application with FastAPI and SQLite

- Set up FastAPI project structure
- Configure SQLite database with SQLAlchemy
- Create Item model and schemas
- Implement CRUD endpoints for inventory items
- Set up Alembic for database migrations
- Add comprehensive documentation

README.md

@@ -1,3 +1,110 @@
-# FastAPI Application
+# Simple Inventory App
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A FastAPI-based inventory management application that provides CRUD operations for managing inventory items.
+
+## Features
+
+- Create, read, update, and delete inventory items
+- Filter items by category
+- Pagination support
+- SQLite database for data persistence
+- Alembic for database migrations
+- Health check endpoint
+
+## API Endpoints
+
+- `GET /`: Root endpoint with basic app information
+- `GET /health`: Health check endpoint
+- `GET /api/v1/items`: List all items (with optional filtering and pagination)
+- `POST /api/v1/items`: Create a new item
+- `GET /api/v1/items/{item_id}`: Get a specific item by ID
+- `PUT /api/v1/items/{item_id}`: Update an existing item
+- `DELETE /api/v1/items/{item_id}`: Delete an item
+
+## Project Structure
+
+```
+.
+├── alembic.ini                  # Alembic configuration
+├── app                          # Application package
+│   ├── api                      # API module
+│   │   ├── v1                   # API version 1
+│   │   │   ├── api.py           # API router
+│   │   │   └── endpoints        # API endpoints
+│   │   │       └── items.py     # Items endpoints
+│   ├── core                     # Core application code
+│   │   └── config.py            # Configuration settings
+│   ├── db                       # Database module
+│   │   ├── base.py              # SQLAlchemy Base
+│   │   ├── base_model.py        # Models import for Alembic
+│   │   └── session.py           # DB session
+│   ├── models                   # SQLAlchemy models
+│   │   └── item.py              # Item model
+│   └── schemas                  # Pydantic schemas
+│       └── item.py              # Item schemas
+├── main.py                      # FastAPI application
+├── migrations                   # Alembic migrations
+│   ├── env.py                   # Alembic environment
+│   ├── README                   # Migrations readme
+│   ├── script.py.mako           # Migration script template
+│   └── versions                 # Migration versions
+│       └── 20240512_initial_tables.py  # Initial migration
+└── requirements.txt             # Project dependencies
+```
+
+## Setup and Installation
+
+1. Install the dependencies:
+   ```
+   pip install -r requirements.txt
+   ```
+
+2. Apply database migrations:
+   ```
+   alembic upgrade head
+   ```
+
+3. Run the application:
+   ```
+   uvicorn main:app --reload
+   ```
+
+4. Access the application:
+   - API documentation: http://localhost:8000/docs
+   - ReDoc: http://localhost:8000/redoc
+   - API root: http://localhost:8000
+   - Health check: http://localhost:8000/health
+
+## Environment Variables
+
+The application uses the following environment variables:
+
+- `PROJECT_NAME`: Name of the project (default: "Simple Inventory App")
+- `BACKEND_CORS_ORIGINS`: List of allowed CORS origins (default: ["*"])
+
+## Inventory Item Model
+
+Each inventory item has the following attributes:
+
+- `id`: Unique identifier (integer)
+- `name`: Item name (string, required)
+- `description`: Item description (string, optional)
+- `quantity`: Available quantity (integer, default: 0)
+- `price`: Item price (float, optional)
+- `category`: Item category (string, optional)
+- `created_at`: Creation timestamp (datetime)
+- `updated_at`: Last update timestamp (datetime)
+
+## Development
+
+### Linting
+
+To lint the code with Ruff:
+```
+ruff check .
+```
+
+To automatically fix linting issues:
+```
+ruff check --fix .
+```

alembic.ini

@@ -0,0 +1,85 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = migrations
+
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# timezone to use when rendering the date
+# within the migration file as well as the filename.
+# 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
+# version_locations = %(here)s/bar %(here)s/bat migrations/versions
+
+# the output encoding used when revision files
+# are written from script.py.mako
+# output_encoding = utf-8
+
+# SQLite URL - use absolute path
+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
+
+# 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 +1,5 @@
+from fastapi import APIRouter
+from app.api.v1.endpoints import items
+
+api_router = APIRouter()
+api_router.include_router(items.router, prefix="/items", tags=["items"])

app/api/v1/endpoints/items.py

@@ -0,0 +1,92 @@
+from typing import List, Optional
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.db.session import get_db
+from app.models.item import Item as ItemModel
+from app.schemas.item import Item, ItemCreate, ItemUpdate
+
+router = APIRouter()
+
+@router.get("/", response_model=List[Item])
+def read_items(
+    skip: int = 0,
+    limit: int = 100,
+    category: Optional[str] = None,
+    db: Session = Depends(get_db)
+):
+    """
+    Retrieve all items with optional filtering by category.
+    """
+    query = db.query(ItemModel)
+    if category:
+        query = query.filter(ItemModel.category == category)
+    return query.offset(skip).limit(limit).all()
+
+
+@router.post("/", response_model=Item, status_code=status.HTTP_201_CREATED)
+def create_item(
+    item_in: ItemCreate,
+    db: Session = Depends(get_db)
+):
+    """
+    Create a new inventory item.
+    """
+    db_item = ItemModel(**item_in.model_dump())
+    db.add(db_item)
+    db.commit()
+    db.refresh(db_item)
+    return db_item
+
+
+@router.get("/{item_id}", response_model=Item)
+def read_item(
+    item_id: int,
+    db: Session = Depends(get_db)
+):
+    """
+    Get a specific item by ID.
+    """
+    db_item = db.query(ItemModel).filter(ItemModel.id == item_id).first()
+    if db_item is None:
+        raise HTTPException(status_code=404, detail="Item not found")
+    return db_item
+
+
+@router.put("/{item_id}", response_model=Item)
+def update_item(
+    item_id: int,
+    item_in: ItemUpdate,
+    db: Session = Depends(get_db)
+):
+    """
+    Update an existing item.
+    """
+    db_item = db.query(ItemModel).filter(ItemModel.id == item_id).first()
+    if db_item is None:
+        raise HTTPException(status_code=404, detail="Item not found")
+    
+    update_data = item_in.model_dump(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(db_item, field, value)
+    
+    db.commit()
+    db.refresh(db_item)
+    return db_item
+
+
+@router.delete("/{item_id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
+def delete_item(
+    item_id: int,
+    db: Session = Depends(get_db)
+):
+    """
+    Delete an item.
+    """
+    db_item = db.query(ItemModel).filter(ItemModel.id == item_id).first()
+    if db_item is None:
+        raise HTTPException(status_code=404, detail="Item not found")
+    
+    db.delete(db_item)
+    db.commit()
+    return None

app/core/config.py

@@ -0,0 +1,24 @@
+from pathlib import Path
+from pydantic_settings import BaseSettings
+
+class Settings(BaseSettings):
+    # Project settings
+    PROJECT_NAME: str = "Simple Inventory App"
+    API_V1_STR: str = "/api/v1"
+    
+    # CORS settings
+    BACKEND_CORS_ORIGINS: list[str] = ["*"]
+
+    # Database settings
+    DB_DIR = Path("/app") / "storage" / "db"
+    SQLALCHEMY_DATABASE_URL: str = f"sqlite:///{DB_DIR}/db.sqlite"
+    
+    class Config:
+        case_sensitive = True
+        env_file = ".env"
+
+# Create the DB directory if it doesn't exist
+Settings().DB_DIR.mkdir(parents=True, exist_ok=True)
+
+# Initialize settings
+settings = Settings()

app/db/base.py

@@ -0,0 +1,3 @@
+from sqlalchemy.ext.declarative import declarative_base
+
+Base = declarative_base()

app/db/base_model.py

@@ -0,0 +1,4 @@
+# Import all the models, so that Base has them before being
+# imported by Alembic
+from app.db.base import Base  # noqa
+from app.models.item import Item  # noqa

app/db/session.py

@@ -0,0 +1,18 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+from app.core.config import settings
+
+engine = create_engine(
+    settings.SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False}  # Required for SQLite
+)
+
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+# Dependency for endpoints to get the DB session
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/__init__.py

@@ -0,0 +1 @@
+from app.models.item import Item  # noqa

app/models/item.py

@@ -0,0 +1,14 @@
+from sqlalchemy import Column, Integer, String, Float, DateTime, func
+from app.db.base import Base
+
+class Item(Base):
+    __tablename__ = "items"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String, index=True)
+    description = Column(String, nullable=True)
+    quantity = Column(Integer, default=0)
+    price = Column(Float, nullable=True)
+    category = Column(String, nullable=True)
+    created_at = Column(DateTime, default=func.now())
+    updated_at = Column(DateTime, default=func.now(), onupdate=func.now())

app/schemas/__init__.py

@@ -0,0 +1 @@
+from app.schemas.item import Item, ItemCreate, ItemUpdate  # noqa

app/schemas/item.py

@@ -0,0 +1,34 @@
+from datetime import datetime
+from typing import Optional
+from pydantic import BaseModel, Field
+
+# Shared properties
+class ItemBase(BaseModel):
+    name: str
+    description: Optional[str] = None
+    quantity: int = Field(default=0, ge=0)
+    price: Optional[float] = Field(default=None, ge=0)
+    category: Optional[str] = None
+
+# Properties to receive on item creation
+class ItemCreate(ItemBase):
+    pass
+
+# Properties to receive on item update
+class ItemUpdate(ItemBase):
+    name: Optional[str] = None
+    quantity: Optional[int] = Field(default=None, ge=0)
+
+# Properties shared by models stored in DB
+class ItemInDBBase(ItemBase):
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        orm_mode = True
+        from_attributes = True
+
+# Properties to return to client
+class Item(ItemInDBBase):
+    pass

main.py

@@ -0,0 +1,45 @@
+import uvicorn
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+from app.api.v1.api import api_router
+from app.core.config import settings
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    openapi_url="/openapi.json",
+    docs_url="/docs",
+    redoc_url="/redoc",
+)
+
+# Set up CORS middleware
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Include API router
+app.include_router(api_router, prefix="/api/v1")
+
+@app.get("/")
+async def root():
+    """
+    Root endpoint that returns basic application information.
+    """
+    return {
+        "title": settings.PROJECT_NAME,
+        "docs": "/docs",
+        "health": "/health"
+    }
+
+@app.get("/health")
+async def health_check():
+    """
+    Health check endpoint.
+    """
+    return {"status": "healthy"}
+
+if __name__ == "__main__":
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

migrations/README

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

migrations/env.py

@@ -0,0 +1,81 @@
+from logging.config import fileConfig
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+from app.db.base_model 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.
+fileConfig(config.config_file_name)
+
+# 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():
+    """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,  # 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():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

migrations/versions/20240512_initial_tables.py

@@ -0,0 +1,42 @@
+"""initial tables
+
+Revision ID: 1a1f28ba16c2
+Revises: 
+Create Date: 2024-05-12 00:00:00.000000
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '1a1f28ba16c2'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('items',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('name', sa.String(), nullable=False),
+        sa.Column('description', sa.String(), nullable=True),
+        sa.Column('quantity', sa.Integer(), nullable=True),
+        sa.Column('price', sa.Float(), nullable=True),
+        sa.Column('category', sa.String(), nullable=True),
+        sa.Column('created_at', sa.DateTime(), nullable=True),
+        sa.Column('updated_at', sa.DateTime(), nullable=True),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_items_id'), 'items', ['id'], unique=False)
+    op.create_index(op.f('ix_items_name'), 'items', ['name'], unique=False)
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_index(op.f('ix_items_name'), table_name='items')
+    op.drop_index(op.f('ix_items_id'), table_name='items')
+    op.drop_table('items')
+    # ### end Alembic commands ###

requirements.txt

@@ -0,0 +1,8 @@
+fastapi>=0.105.0
+uvicorn>=0.25.0
+sqlalchemy>=2.0.20
+pydantic>=2.5.0
+pydantic-settings>=2.1.0
+alembic>=1.12.0
+python-dotenv>=1.0.0
+ruff>=0.1.6