fastapi-settings

name	fastapi-settings
description	Set up pydantic-settings configuration for a FastAPI project with environment variables, .env file support, and dependency injection.

Set Up FastAPI Settings

When to Use

Use this skill when a FastAPI project has hardcoded configuration or needs environment-based settings.

Instructions

1. Check if pydantic-settings is installed. If not, suggest adding it.

2. Generate the Settings class:

   from pydantic_settings import BaseSettings, SettingsConfigDict
   from functools import lru_cache
   
   class Settings(BaseSettings):
       # App
       app_name: str = "My API"
       debug: bool = False
   
       # Database
       database_url: str
   
       # Auth
       secret_key: str
       access_token_expire_minutes: int = 30
   
       # External services
       redis_url: str = "redis://localhost:6379"
   
       model_config = SettingsConfigDict(
           env_file=".env",
           env_file_encoding="utf-8",
           case_sensitive=False,
       )
   
   @lru_cache
   def get_settings() -> Settings:
       return Settings()
   

3. Generate .env.example with all required variables.

4. Set up dependency injection:

   from typing import Annotated
   from fastapi import Depends
   
   SettingsDep = Annotated[Settings, Depends(get_settings)]
   

5. Show how to override in tests:

   def get_settings_override():
       return Settings(database_url="sqlite+aiosqlite:///:memory:")
   
   app.dependency_overrides[get_settings] = get_settings_override