Python configuration management via environment variables and typed settings. Use when externalizing config, setting up pydantic-settings, managing secrets, or implementing environment-specific behavior.
Externalize configuration from code using environment variables and typed settings. Well-managed configuration enables the same code to run in any environment without modification.
All environment-specific values (URLs, secrets, feature flags) come from environment variables, not code.
Parse and validate configuration into typed objects at startup, not scattered throughout code.
Validate all required configuration at application boot. Missing config should crash immediately with a clear message.
Provide reasonable defaults for local development while requiring explicit values for sensitive settings.
from pydantic_settings import BaseSettings
from pydantic import Field
class Settings(BaseSettings):
database_url: str = Field(alias="DATABASE_URL")
api_key: str = Field(alias="API_KEY")
debug: bool = Field(default=False, alias="DEBUG")
settings = Settings() # Loads from environment
Create a central settings class that loads and validates all configuration.
from pydantic_settings import BaseSettings
from pydantic import Field, PostgresDsn, ValidationError
import sys
class Settings(BaseSettings):
"""Application configuration loaded from environment variables."""
# Database
db_host: str = Field(alias="DB_HOST")
db_port: int = Field(default=5432, alias="DB_PORT")
db_name: str = Field(alias="DB_NAME")
db_user: str = Field(alias="DB_USER")
db_password: str = Field(alias="DB_PASSWORD")
# Redis
redis_url: str = Field(default="redis://localhost:6379", alias="REDIS_URL")
# API Keys
api_secret_key: str = Field(alias="API_SECRET_KEY")
# Feature flags
enable_new_feature: bool = Field(default=False, alias="ENABLE_NEW_FEATURE")
model_config = {
"env_file": ".env",
"env_file_encoding": "utf-8",
}
# Create singleton instance at module load