The twelve-factor app methodology tells us: store config in the environment. It’s good advice. Environment variables separate config from code, making the same artifact deployable across environments.
But “store config in environment variables” doesn’t mean “scatter random ENV vars everywhere and hope for the best.” Done poorly, environment configuration becomes untraceable, untestable, and unmaintainable.
The Baseline Pattern Centralize environment variable access:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 import os from dataclasses import dataclass from typing import Optional @dataclass class Config: database_url: str redis_url: str api_key: str debug: bool max_workers: int log_level: str @classmethod def from_env(cls) -> 'Config': return cls( database_url=os.environ['DATABASE_URL'], redis_url=os.environ['REDIS_URL'], api_key=os.environ['API_KEY'], debug=os.environ.get('DEBUG', 'false').lower() == 'true', max_workers=int(os.environ.get('MAX_WORKERS', '4')), log_level=os.environ.get('LOG_LEVEL', 'INFO'), ) # Single source of truth config = Config.from_env() Benefits:
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