Create FastAPI inventory management system for small businesses

- Set up FastAPI application with SQLite database
- Implemented CRUD operations for inventory items, categories, and suppliers
- Added Alembic migrations for database schema management
- Configured CORS middleware for cross-origin requests
- Added health check and API documentation endpoints
- Structured project with proper separation of concerns
- Added comprehensive README with API documentation

README.md

@@ -1,3 +1,93 @@
-# FastAPI Application
+# Small Business Inventory Management System
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A FastAPI-based inventory management system designed for small businesses to track their inventory, suppliers, and product categories.
+
+## Features
+
+- **Inventory Management**: Complete CRUD operations for inventory items
+- **Category Management**: Organize products by categories
+- **Supplier Management**: Track supplier information and relationships
+- **Low Stock Alerts**: Filter items by low stock levels
+- **RESTful API**: Full REST API with automatic documentation
+- **Database Migrations**: Alembic for database schema management
+
+## API Endpoints
+
+### Inventory Items
+- `GET /api/inventory/items` - List all inventory items (with optional filters)
+- `GET /api/inventory/items/{item_id}` - Get specific inventory item
+- `POST /api/inventory/items` - Create new inventory item
+- `PUT /api/inventory/items/{item_id}` - Update inventory item
+- `DELETE /api/inventory/items/{item_id}` - Delete inventory item
+
+### Categories
+- `GET /api/inventory/categories` - List all categories
+- `GET /api/inventory/categories/{category_id}` - Get specific category
+- `POST /api/inventory/categories` - Create new category
+- `PUT /api/inventory/categories/{category_id}` - Update category
+- `DELETE /api/inventory/categories/{category_id}` - Delete category
+
+### Suppliers
+- `GET /api/inventory/suppliers` - List all suppliers
+- `GET /api/inventory/suppliers/{supplier_id}` - Get specific supplier
+- `POST /api/inventory/suppliers` - Create new supplier
+- `PUT /api/inventory/suppliers/{supplier_id}` - Update supplier
+- `DELETE /api/inventory/suppliers/{supplier_id}` - Delete supplier
+
+### System Endpoints
+- `GET /` - API information and links
+- `GET /health` - Health check endpoint
+- `GET /docs` - Interactive API documentation (Swagger UI)
+- `GET /redoc` - Alternative API documentation
+
+## Quick Start
+
+1. Install dependencies:
+   ```bash
+   pip install -r requirements.txt
+   ```
+
+2. Run database migrations:
+   ```bash
+   alembic upgrade head
+   ```
+
+3. Start the development server:
+   ```bash
+   uvicorn main:app --reload
+   ```
+
+The API will be available at `http://localhost:8000`
+
+## Documentation
+
+- Interactive API docs: `http://localhost:8000/docs`
+- Alternative docs: `http://localhost:8000/redoc`
+- OpenAPI JSON: `http://localhost:8000/openapi.json`
+
+## Database
+
+This application uses SQLite as the database backend. The database file is stored at `/app/storage/db/db.sqlite`.
+
+## Project Structure
+
+```
+├── main.py                     # FastAPI application entry point
+├── requirements.txt           # Python dependencies
+├── alembic.ini               # Alembic configuration
+├── alembic/                  # Database migrations
+│   ├── env.py
+│   ├── script.py.mako
+│   └── versions/
+│       └── 001_initial_migration.py
+└── app/
+    ├── api/
+    │   └── inventory.py      # API endpoints
+    ├── db/
+    │   ├── base.py          # SQLAlchemy base
+    │   └── session.py       # Database session
+    ├── models/
+    │   └── inventory.py     # Database models
+    └── schemas/
+        └── inventory.py     # Pydantic schemas
+```

alembic.ini

@@ -0,0 +1,43 @@
+[alembic]
+script_location = alembic
+prepend_sys_path = .
+version_path_separator = os
+sqlalchemy.url = sqlite:////app/storage/db/db.sqlite
+
+[post_write_hooks]
+
+[alembic:exclude]
+
+[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 +1,53 @@
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+
+import sys
+import os
+
+sys.path.append(os.path.dirname(os.path.dirname(os.path.realpath(__file__))))
+
+from app.db.base import Base
+
+config = context.config
+
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+target_metadata = Base.metadata
+
+
+def run_migrations_offline() -> None:
+    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:
+    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() -> None:
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    ${downgrades if downgrades else "pass"}

alembic/versions/001_initial_migration.py

@@ -0,0 +1,102 @@
+"""Initial migration
+
+Revision ID: 001
+Revises:
+Create Date: 2024-01-01 00:00:00.000000
+
+"""
+
+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:
+    # Create categories table
+    op.create_table(
+        "categories",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("name", sa.String(length=100), nullable=False),
+        sa.Column("description", sa.Text()),
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.text("CURRENT_TIMESTAMP"),
+        ),
+        sa.Column("updated_at", sa.DateTime(timezone=True)),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(op.f("ix_categories_id"), "categories", ["id"], unique=False)
+    op.create_index(op.f("ix_categories_name"), "categories", ["name"], unique=True)
+
+    # Create suppliers table
+    op.create_table(
+        "suppliers",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("name", sa.String(length=200), nullable=False),
+        sa.Column("contact_person", sa.String(length=100)),
+        sa.Column("email", sa.String(length=100)),
+        sa.Column("phone", sa.String(length=20)),
+        sa.Column("address", sa.Text()),
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.text("CURRENT_TIMESTAMP"),
+        ),
+        sa.Column("updated_at", sa.DateTime(timezone=True)),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(op.f("ix_suppliers_id"), "suppliers", ["id"], unique=False)
+    op.create_index(op.f("ix_suppliers_name"), "suppliers", ["name"], unique=True)
+
+    # Create inventory_items table
+    op.create_table(
+        "inventory_items",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("name", sa.String(length=200), nullable=False),
+        sa.Column("sku", sa.String(length=50), nullable=False),
+        sa.Column("description", sa.Text()),
+        sa.Column("category_id", sa.Integer()),
+        sa.Column("supplier_id", sa.Integer()),
+        sa.Column("quantity", sa.Integer(), default=0),
+        sa.Column("min_quantity", sa.Integer(), default=0),
+        sa.Column("unit_price", sa.Float(), nullable=False),
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.text("CURRENT_TIMESTAMP"),
+        ),
+        sa.Column("updated_at", sa.DateTime(timezone=True)),
+        sa.ForeignKeyConstraint(["category_id"], ["categories.id"]),
+        sa.ForeignKeyConstraint(["supplier_id"], ["suppliers.id"]),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(
+        op.f("ix_inventory_items_id"), "inventory_items", ["id"], unique=False
+    )
+    op.create_index(
+        op.f("ix_inventory_items_name"), "inventory_items", ["name"], unique=False
+    )
+    op.create_index(
+        op.f("ix_inventory_items_sku"), "inventory_items", ["sku"], unique=True
+    )
+
+
+def downgrade() -> None:
+    op.drop_index(op.f("ix_inventory_items_sku"), table_name="inventory_items")
+    op.drop_index(op.f("ix_inventory_items_name"), table_name="inventory_items")
+    op.drop_index(op.f("ix_inventory_items_id"), table_name="inventory_items")
+    op.drop_table("inventory_items")
+
+    op.drop_index(op.f("ix_suppliers_name"), table_name="suppliers")
+    op.drop_index(op.f("ix_suppliers_id"), table_name="suppliers")
+    op.drop_table("suppliers")
+
+    op.drop_index(op.f("ix_categories_name"), table_name="categories")
+    op.drop_index(op.f("ix_categories_id"), table_name="categories")
+    op.drop_table("categories")

app/api/inventory.py

@@ -0,0 +1,190 @@
+from typing import List, Optional
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy.orm import Session
+from app.db.session import SessionLocal
+from app.models.inventory import InventoryItem, Category, Supplier
+from app.schemas.inventory import (
+    InventoryItem as InventoryItemSchema,
+    InventoryItemCreate,
+    InventoryItemUpdate,
+    Category as CategorySchema,
+    CategoryCreate,
+    CategoryUpdate,
+    Supplier as SupplierSchema,
+    SupplierCreate,
+    SupplierUpdate,
+)
+
+router = APIRouter()
+
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+
+@router.get("/items", response_model=List[InventoryItemSchema])
+def get_inventory_items(
+    skip: int = 0,
+    limit: int = 100,
+    category_id: Optional[int] = None,
+    low_stock: bool = False,
+    db: Session = Depends(get_db),
+):
+    query = db.query(InventoryItem)
+
+    if category_id:
+        query = query.filter(InventoryItem.category_id == category_id)
+
+    if low_stock:
+        query = query.filter(InventoryItem.quantity <= InventoryItem.min_quantity)
+
+    return query.offset(skip).limit(limit).all()
+
+
+@router.get("/items/{item_id}", response_model=InventoryItemSchema)
+def get_inventory_item(item_id: int, db: Session = Depends(get_db)):
+    item = db.query(InventoryItem).filter(InventoryItem.id == item_id).first()
+    if not item:
+        raise HTTPException(status_code=404, detail="Item not found")
+    return item
+
+
+@router.post("/items", response_model=InventoryItemSchema)
+def create_inventory_item(item: InventoryItemCreate, db: Session = Depends(get_db)):
+    db_item = InventoryItem(**item.dict())
+    db.add(db_item)
+    db.commit()
+    db.refresh(db_item)
+    return db_item
+
+
+@router.put("/items/{item_id}", response_model=InventoryItemSchema)
+def update_inventory_item(
+    item_id: int, item_update: InventoryItemUpdate, db: Session = Depends(get_db)
+):
+    db_item = db.query(InventoryItem).filter(InventoryItem.id == item_id).first()
+    if not db_item:
+        raise HTTPException(status_code=404, detail="Item not found")
+
+    update_data = item_update.dict(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("/items/{item_id}")
+def delete_inventory_item(item_id: int, db: Session = Depends(get_db)):
+    db_item = db.query(InventoryItem).filter(InventoryItem.id == item_id).first()
+    if not db_item:
+        raise HTTPException(status_code=404, detail="Item not found")
+
+    db.delete(db_item)
+    db.commit()
+    return {"message": "Item deleted successfully"}
+
+
+@router.get("/categories", response_model=List[CategorySchema])
+def get_categories(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
+    return db.query(Category).offset(skip).limit(limit).all()
+
+
+@router.get("/categories/{category_id}", response_model=CategorySchema)
+def get_category(category_id: int, db: Session = Depends(get_db)):
+    category = db.query(Category).filter(Category.id == category_id).first()
+    if not category:
+        raise HTTPException(status_code=404, detail="Category not found")
+    return category
+
+
+@router.post("/categories", response_model=CategorySchema)
+def create_category(category: CategoryCreate, db: Session = Depends(get_db)):
+    db_category = Category(**category.dict())
+    db.add(db_category)
+    db.commit()
+    db.refresh(db_category)
+    return db_category
+
+
+@router.put("/categories/{category_id}", response_model=CategorySchema)
+def update_category(
+    category_id: int, category_update: CategoryUpdate, db: Session = Depends(get_db)
+):
+    db_category = db.query(Category).filter(Category.id == category_id).first()
+    if not db_category:
+        raise HTTPException(status_code=404, detail="Category not found")
+
+    update_data = category_update.dict(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(db_category, field, value)
+
+    db.commit()
+    db.refresh(db_category)
+    return db_category
+
+
+@router.delete("/categories/{category_id}")
+def delete_category(category_id: int, db: Session = Depends(get_db)):
+    db_category = db.query(Category).filter(Category.id == category_id).first()
+    if not db_category:
+        raise HTTPException(status_code=404, detail="Category not found")
+
+    db.delete(db_category)
+    db.commit()
+    return {"message": "Category deleted successfully"}
+
+
+@router.get("/suppliers", response_model=List[SupplierSchema])
+def get_suppliers(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
+    return db.query(Supplier).offset(skip).limit(limit).all()
+
+
+@router.get("/suppliers/{supplier_id}", response_model=SupplierSchema)
+def get_supplier(supplier_id: int, db: Session = Depends(get_db)):
+    supplier = db.query(Supplier).filter(Supplier.id == supplier_id).first()
+    if not supplier:
+        raise HTTPException(status_code=404, detail="Supplier not found")
+    return supplier
+
+
+@router.post("/suppliers", response_model=SupplierSchema)
+def create_supplier(supplier: SupplierCreate, db: Session = Depends(get_db)):
+    db_supplier = Supplier(**supplier.dict())
+    db.add(db_supplier)
+    db.commit()
+    db.refresh(db_supplier)
+    return db_supplier
+
+
+@router.put("/suppliers/{supplier_id}", response_model=SupplierSchema)
+def update_supplier(
+    supplier_id: int, supplier_update: SupplierUpdate, db: Session = Depends(get_db)
+):
+    db_supplier = db.query(Supplier).filter(Supplier.id == supplier_id).first()
+    if not db_supplier:
+        raise HTTPException(status_code=404, detail="Supplier not found")
+
+    update_data = supplier_update.dict(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(db_supplier, field, value)
+
+    db.commit()
+    db.refresh(db_supplier)
+    return db_supplier
+
+
+@router.delete("/suppliers/{supplier_id}")
+def delete_supplier(supplier_id: int, db: Session = Depends(get_db)):
+    db_supplier = db.query(Supplier).filter(Supplier.id == supplier_id).first()
+    if not db_supplier:
+        raise HTTPException(status_code=404, detail="Supplier not found")
+
+    db.delete(db_supplier)
+    db.commit()
+    return {"message": "Supplier deleted successfully"}

app/db/base.py

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

app/db/session.py

@@ -0,0 +1,14 @@
+from pathlib import Path
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+
+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)

app/models/inventory.py

@@ -0,0 +1,50 @@
+from sqlalchemy import Column, Integer, String, Float, DateTime, ForeignKey, Text
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+from app.db.base import Base
+
+
+class Category(Base):
+    __tablename__ = "categories"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String(100), unique=True, index=True, nullable=False)
+    description = Column(Text)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
+
+    items = relationship("InventoryItem", back_populates="category")
+
+
+class Supplier(Base):
+    __tablename__ = "suppliers"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String(200), unique=True, index=True, nullable=False)
+    contact_person = Column(String(100))
+    email = Column(String(100))
+    phone = Column(String(20))
+    address = Column(Text)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
+
+    items = relationship("InventoryItem", back_populates="supplier")
+
+
+class InventoryItem(Base):
+    __tablename__ = "inventory_items"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String(200), index=True, nullable=False)
+    sku = Column(String(50), unique=True, index=True, nullable=False)
+    description = Column(Text)
+    category_id = Column(Integer, ForeignKey("categories.id"))
+    supplier_id = Column(Integer, ForeignKey("suppliers.id"))
+    quantity = Column(Integer, default=0)
+    min_quantity = Column(Integer, default=0)
+    unit_price = Column(Float, nullable=False)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
+
+    category = relationship("Category", back_populates="items")
+    supplier = relationship("Supplier", back_populates="items")

app/schemas/inventory.py

@@ -0,0 +1,92 @@
+from datetime import datetime
+from typing import Optional
+from pydantic import BaseModel
+
+
+class CategoryBase(BaseModel):
+    name: str
+    description: Optional[str] = None
+
+
+class CategoryCreate(CategoryBase):
+    pass
+
+
+class CategoryUpdate(BaseModel):
+    name: Optional[str] = None
+    description: Optional[str] = None
+
+
+class Category(CategoryBase):
+    id: int
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        from_attributes = True
+
+
+class SupplierBase(BaseModel):
+    name: str
+    contact_person: Optional[str] = None
+    email: Optional[str] = None
+    phone: Optional[str] = None
+    address: Optional[str] = None
+
+
+class SupplierCreate(SupplierBase):
+    pass
+
+
+class SupplierUpdate(BaseModel):
+    name: Optional[str] = None
+    contact_person: Optional[str] = None
+    email: Optional[str] = None
+    phone: Optional[str] = None
+    address: Optional[str] = None
+
+
+class Supplier(SupplierBase):
+    id: int
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        from_attributes = True
+
+
+class InventoryItemBase(BaseModel):
+    name: str
+    sku: str
+    description: Optional[str] = None
+    category_id: Optional[int] = None
+    supplier_id: Optional[int] = None
+    quantity: int = 0
+    min_quantity: int = 0
+    unit_price: float
+
+
+class InventoryItemCreate(InventoryItemBase):
+    pass
+
+
+class InventoryItemUpdate(BaseModel):
+    name: Optional[str] = None
+    sku: Optional[str] = None
+    description: Optional[str] = None
+    category_id: Optional[int] = None
+    supplier_id: Optional[int] = None
+    quantity: Optional[int] = None
+    min_quantity: Optional[int] = None
+    unit_price: Optional[float] = None
+
+
+class InventoryItem(InventoryItemBase):
+    id: int
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+    category: Optional[Category] = None
+    supplier: Optional[Supplier] = None
+
+    class Config:
+        from_attributes = True

main.py

@@ -0,0 +1,33 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+from app.api.inventory import router as inventory_router
+
+app = FastAPI(
+    title="Small Business Inventory Management System",
+    description="A FastAPI-based inventory management system for small businesses",
+    version="1.0.0",
+)
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+app.include_router(inventory_router, prefix="/api/inventory", tags=["inventory"])
+
+
+@app.get("/")
+def read_root():
+    return {
+        "title": "Small Business Inventory Management System",
+        "documentation": "/docs",
+        "health_check": "/health",
+    }
+
+
+@app.get("/health")
+def health_check():
+    return {"status": "healthy", "service": "inventory-management-system"}

requirements.txt

@@ -0,0 +1,7 @@
+fastapi==0.104.1
+uvicorn[standard]==0.24.0
+sqlalchemy==2.0.23
+alembic==1.13.1
+pydantic==2.5.0
+python-multipart==0.0.6
+ruff==0.1.6