Create simple FastAPI application with SQLite and Alembic

- Set up project structure
- Create FastAPI app with health endpoint
- Implement SQLAlchemy with SQLite database
- Set up Alembic for database migrations
- Create CRUD operations for items
- Add comprehensive documentation

README.md

@@ -1,3 +1,98 @@
-# FastAPI Application
+# Simple FastAPI Application
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+This is a simple FastAPI application with SQLite database integration, built to demonstrate best practices for API development with FastAPI.
+
+## Features
+
+- RESTful API with FastAPI
+- SQLite database with SQLAlchemy ORM
+- Database migrations with Alembic
+- CRUD operations for items
+- Health check endpoint
+- OpenAPI documentation
+- Code linting with Ruff
+
+## Project Structure
+
+```
+├── app/
+│   ├── api/
+│   │   ├── endpoints/
+│   │   │   ├── health.py
+│   │   │   └── items.py
+│   ├── core/
+│   │   └── config.py
+│   ├── db/
+│   │   └── session.py
+│   ├── models/
+│   │   └── models.py
+│   ├── schemas/
+│   │   └── item.py
+│   └── storage/
+│       └── db/
+├── migrations/
+│   ├── versions/
+│   │   └── 47e3b63e1a20_create_items_table.py
+│   ├── env.py
+│   └── script.py.mako
+├── alembic.ini
+├── main.py
+├── README.md
+└── requirements.txt
+```
+
+## Installation
+
+1. Clone the repository
+2. Install dependencies:
+
+```bash
+pip install -r requirements.txt
+```
+
+## Running the Application
+
+Start the application with uvicorn:
+
+```bash
+uvicorn main:app --host 0.0.0.0 --port 8000 --reload
+```
+
+## API Documentation
+
+Once the application is running, you can access:
+
+- Swagger UI: [http://localhost:8000/docs](http://localhost:8000/docs)
+- ReDoc: [http://localhost:8000/redoc](http://localhost:8000/redoc)
+
+## API Endpoints
+
+### Health Check
+
+- `GET /health` - Check if the API and database are running
+
+### Items
+
+- `GET /api/v1/items` - Get all items
+- `GET /api/v1/items/{item_id}` - Get an item by ID
+- `POST /api/v1/items` - Create a new item
+- `PATCH /api/v1/items/{item_id}` - Update an item
+- `DELETE /api/v1/items/{item_id}` - Delete an item
+
+## Database Migrations
+
+Run migrations:
+
+```bash
+alembic upgrade head
+```
+
+Create a new migration:
+
+```bash
+alembic revision --autogenerate -m "description"
+```
+
+## License
+
+MIT

alembic.ini

@@ -0,0 +1,74 @@
+# 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 using absolute path
+sqlalchemy.url = sqlite:////app/storage/db/db.sqlite
+
+# 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/endpoints/__init__.py

@@ -0,0 +1 @@
+# Module init file

app/api/endpoints/health.py

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+from fastapi import APIRouter, Depends
+from sqlalchemy.orm import Session
+from app.db.session import get_db
+
+
+router = APIRouter()
+
+
+@router.get("/health", summary="Health check endpoint")
+def health_check(db: Session = Depends(get_db)):
+    """
+    Health check endpoint to verify that the API is running and can connect to the database.
+
+    Returns:
+        dict: A JSON object with the status of the service and database connection
+    """
+    db_status = "healthy"
+    try:
+        # Try to execute a simple query
+        db.execute("SELECT 1")
+    except Exception:
+        db_status = "unhealthy"
+
+    return {"status": "ok", "database": db_status}

app/api/endpoints/items.py

@@ -0,0 +1,133 @@
+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 import models
+from app.schemas.item import Item, ItemCreate, ItemUpdate
+
+router = APIRouter()
+
+
+@router.post("/items/", response_model=Item, status_code=status.HTTP_201_CREATED)
+def create_item(item: ItemCreate, db: Session = Depends(get_db)):
+    """
+    Create a new item.
+
+    Args:
+        item: The item data to create
+        db: Database session
+
+    Returns:
+        The created item
+    """
+    db_item = models.Item(**item.model_dump())
+    db.add(db_item)
+    db.commit()
+    db.refresh(db_item)
+    return db_item
+
+
+@router.get("/items/", response_model=List[Item])
+def read_items(
+    skip: int = 0,
+    limit: int = 100,
+    name: Optional[str] = None,
+    db: Session = Depends(get_db),
+):
+    """
+    Retrieve items with optional filtering.
+
+    Args:
+        skip: Number of items to skip
+        limit: Maximum number of items to return
+        name: Optional filter by item name
+        db: Database session
+
+    Returns:
+        List of items
+    """
+    query = db.query(models.Item)
+
+    if name:
+        query = query.filter(models.Item.name.ilike(f"%{name}%"))
+
+    items = query.offset(skip).limit(limit).all()
+    return items
+
+
+@router.get("/items/{item_id}", response_model=Item)
+def read_item(item_id: int, db: Session = Depends(get_db)):
+    """
+    Get item by ID.
+
+    Args:
+        item_id: The ID of the item to retrieve
+        db: Database session
+
+    Returns:
+        The requested item
+
+    Raises:
+        HTTPException: If item is not found
+    """
+    item = db.query(models.Item).filter(models.Item.id == item_id).first()
+    if item is None:
+        raise HTTPException(status_code=404, detail="Item not found")
+    return item
+
+
+@router.patch("/items/{item_id}", response_model=Item)
+def update_item(item_id: int, item_update: ItemUpdate, db: Session = Depends(get_db)):
+    """
+    Update an item.
+
+    Args:
+        item_id: The ID of the item to update
+        item_update: The updated item data
+        db: Database session
+
+    Returns:
+        The updated item
+
+    Raises:
+        HTTPException: If item is not found
+    """
+    db_item = db.query(models.Item).filter(models.Item.id == item_id).first()
+    if db_item is None:
+        raise HTTPException(status_code=404, detail="Item not found")
+
+    # Update item attributes that are provided
+    update_data = item_update.model_dump(exclude_unset=True)
+    for key, value in update_data.items():
+        setattr(db_item, key, value)
+
+    db.commit()
+    db.refresh(db_item)
+    return db_item
+
+
+@router.delete(
+    "/items/{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.
+
+    Args:
+        item_id: The ID of the item to delete
+        db: Database session
+
+    Returns:
+        None
+
+    Raises:
+        HTTPException: If item is not found
+    """
+    db_item = db.query(models.Item).filter(models.Item.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 +1,19 @@
+from typing import List
+from pydantic_settings import BaseSettings
+
+
+class Settings(BaseSettings):
+    PROJECT_NAME: str = "Simple FastAPI Application"
+    PROJECT_DESCRIPTION: str = "A simple FastAPI application with SQLite database"
+    PROJECT_VERSION: str = "0.1.0"
+
+    API_V1_STR: str = "/api/v1"
+
+    # CORS settings
+    ALLOWED_ORIGINS: List[str] = ["*"]
+
+    class Config:
+        case_sensitive = True
+
+
+settings = Settings()

app/db/session.py

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+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+from pathlib import Path
+
+# Create the database directory if it doesn't exist
+DB_DIR = Path("/app") / "storage" / "db"
+DB_DIR.mkdir(parents=True, exist_ok=True)
+
+# Database URL
+SQLALCHEMY_DATABASE_URL = f"sqlite:///{DB_DIR}/db.sqlite"
+
+# Create SQLAlchemy engine
+engine = create_engine(
+    SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False},  # SQLite specific
+)
+
+# Create a session factory
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+# Create a Base class for model declaration
+Base = declarative_base()
+
+
+# Dependency for database session
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/__init__.py

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+# Module init file

app/models/models.py

@@ -0,0 +1,15 @@
+from sqlalchemy import Column, Integer, String, Boolean, DateTime
+from sqlalchemy.sql import func
+from app.db.session import Base
+
+
+class Item(Base):
+    __tablename__ = "items"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String, index=True)
+    description = Column(String)
+    price = Column(Integer)  # Price in cents
+    is_active = Column(Boolean, default=True)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())

app/schemas/__init__.py

@@ -0,0 +1 @@
+# Module init file

app/schemas/item.py

@@ -0,0 +1,34 @@
+from datetime import datetime
+from typing import Optional
+from pydantic import BaseModel
+
+
+class ItemBase(BaseModel):
+    name: str
+    description: Optional[str] = None
+    price: int  # Price in cents
+    is_active: bool = True
+
+
+class ItemCreate(ItemBase):
+    pass
+
+
+class ItemUpdate(BaseModel):
+    name: Optional[str] = None
+    description: Optional[str] = None
+    price: Optional[int] = None
+    is_active: Optional[bool] = None
+
+
+class ItemInDB(ItemBase):
+    id: int
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        from_attributes = True
+
+
+class Item(ItemInDB):
+    pass

main.py

@@ -0,0 +1,36 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+import uvicorn
+
+from app.api.endpoints import health, items
+from app.core.config import settings
+from app.db.session import engine
+from app.models import models
+
+# Create database tables
+models.Base.metadata.create_all(bind=engine)
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    description=settings.PROJECT_DESCRIPTION,
+    version=settings.PROJECT_VERSION,
+    openapi_url=f"{settings.API_V1_STR}/openapi.json",
+    docs_url="/docs",
+    redoc_url="/redoc",
+)
+
+# Set up CORS middleware
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=settings.ALLOWED_ORIGINS,
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Include routers
+app.include_router(health.router, tags=["health"])
+app.include_router(items.router, prefix=settings.API_V1_STR, tags=["items"])
+
+if __name__ == "__main__":
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

migrations/env.py

@@ -0,0 +1,69 @@
+import os
+import sys
+from logging.config import fileConfig
+
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+
+# Add the project directory to the sys.path
+sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+# Import the SQLAlchemy models
+from app.db.session import Base
+
+# This is the Alembic Config object
+config = context.config
+
+# Interpret the config file for Python logging
+fileConfig(config.config_file_name)
+
+# Set target metadata for autogenerate
+target_metadata = Base.metadata
+
+
+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.
+    """
+    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,  # This is important for SQLite to handle migrations properly
+        )
+
+        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/47e3b63e1a20_create_items_table.py

@@ -0,0 +1,44 @@
+"""create items table
+
+Revision ID: 47e3b63e1a20
+Revises:
+Create Date: 2023-10-12 10:00:00.000000
+
+"""
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = "47e3b63e1a20"
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.create_table(
+        "items",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("name", sa.String(), nullable=True),
+        sa.Column("description", sa.String(), nullable=True),
+        sa.Column("price", sa.Integer(), nullable=True),
+        sa.Column("is_active", sa.Boolean(), nullable=True, default=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_items_id"), "items", ["id"], unique=False)
+    op.create_index(op.f("ix_items_name"), "items", ["name"], unique=False)
+
+
+def downgrade():
+    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")

requirements.txt

@@ -0,0 +1,9 @@
+fastapi>=0.100.0
+uvicorn>=0.23.0
+sqlalchemy>=2.0.0
+alembic>=1.12.0
+pydantic>=2.4.0
+pydantic-settings>=2.0.0
+python-multipart>=0.0.6
+email-validator>=2.0.0
+ruff>=0.0.284