Store config in the environment

Store config in the environment

https://12factor.net/config

The twelve-factor app stores config in environment variables (often shortened to env vars or env). Env vars are easy to change between deploys without changing any code; unlike config files, there is little chance of them being checked into the code repo accidentally; and unlike custom config files, or other config mechanisms such as Java System Properties, they are a language- and OS-agnostic standard.

 

pydantic_settings

https://fastapi.tiangolo.com/advanced/settings/#reading-a-env-file

fastapi推荐

 

https://docs.pydantic.dev/latest/concepts/pydantic_settings/#usage

from typing import Any, Callable, Set

from pydantic import (
    AliasChoices,
    AmqpDsn,
    BaseModel,
    Field,
    ImportString,
    PostgresDsn,
    RedisDsn,
)

from pydantic_settings import BaseSettings, SettingsConfigDict


class SubModel(BaseModel):
    foo: str = 'bar'
    apple: int = 1


class Settings(BaseSettings):
    auth_key: str = Field(validation_alias='my_auth_key')  

    api_key: str = Field(alias='my_api_key')  

    redis_dsn: RedisDsn = Field(
        'redis://user:pass@localhost:6379/1',
        validation_alias=AliasChoices('service_redis_dsn', 'redis_url'),  (3)
    )
    pg_dsn: PostgresDsn = 'postgres://user:pass@localhost:5432/foobar'
    amqp_dsn: AmqpDsn = 'amqp://user:pass@localhost:5672/'

    special_function: ImportString[Callable[[Any], Any]] = 'math.cos'  (4)

    # to override domains:
    # export my_prefix_domains='["foo.com", "bar.com"]'
    domains: Set[str] = set()

    # to override more_settings:
    # export my_prefix_more_settings='{"foo": "x", "apple": 1}'
    more_settings: SubModel = SubModel()

    model_config = SettingsConfigDict(env_prefix='my_prefix_')  (5)


print(Settings().model_dump())
"""
{
    'auth_key': 'xxx',
    'api_key': 'xxx',
    'redis_dsn': Url('redis://user:pass@localhost:6379/1'),
    'pg_dsn': MultiHostUrl('postgres://user:pass@localhost:5432/foobar'),
    'amqp_dsn': Url('amqp://user:pass@localhost:5672/'),
    'special_function': math.cos,
    'domains': set(),
    'more_settings': {'foo': 'bar', 'apple': 1},
}
"""

 

使用.env覆盖默认值， 但是最终环境会覆盖.env值

from pydantic_settings import BaseSettings, SettingsConfigDict

'''
default -> env file -> env variable
'''
class Settings(BaseSettings):
    PATH: str = "Awesome API"
    USER: str = "xxx"
    TEST: str = "yyy"

    model_config = SettingsConfigDict(env_file=".env")

if __name__ == "__main__":
    src.machine_learning_workflow_pipeline()

    print("---------------------------")
    print(Settings().PATH)
    print(Settings().USER)
    print(Settings().TEST)

 

https://docs.pydantic.org.cn/latest/concepts/pydantic_settings/#parsing-environment-variable-values

例如，给定以下环境变量

 

# your environment
export V0=0
export SUB_MODEL='{"v1": "json-1", "v2": "json-2"}'
export SUB_MODEL__V2=nested-2
export SUB_MODEL__V3=3
export SUB_MODEL__DEEP__V4=v4

 

您可以将它们加载到以下设置模型中

 

from pydantic import BaseModel

from pydantic_settings import BaseSettings, SettingsConfigDict


class DeepSubModel(BaseModel):  

    v4: str


class SubModel(BaseModel):  

    v1: str
    v2: bytes
    v3: int
    deep: DeepSubModel


class Settings(BaseSettings):
    model_config = SettingsConfigDict(env_nested_delimiter='__')

    v0: str
    sub_model: SubModel


print(Settings().model_dump())
"""
{
    'v0': '0',
    'sub_model': {'v1': 'json-1', 'v2': b'nested-2', 'v3': 3, 'deep': {'v4': 'v4'}},
}
"""

 

 

 

fastapi项目模版

https://github.com/fastapi/full-stack-fastapi-template/blob/master/backend/app/core/config.py

import secrets
import warnings
from typing import Annotated, Any, Literal

from pydantic import (
    AnyUrl,
    BeforeValidator,
    HttpUrl,
    PostgresDsn,
    computed_field,
    model_validator,
)
from pydantic_core import MultiHostUrl
from pydantic_settings import BaseSettings, SettingsConfigDict
from typing_extensions import Self


def parse_cors(v: Any) -> list[str] | str:
    if isinstance(v, str) and not v.startswith("["):
        return [i.strip() for i in v.split(",")]
    elif isinstance(v, list | str):
        return v
    raise ValueError(v)


class Settings(BaseSettings):
    model_config = SettingsConfigDict(
        # Use top level .env file (one level above ./backend/)
        env_file="../.env",
        env_ignore_empty=True,
        extra="ignore",
    )
    API_V1_STR: str = "/api/v1"
    SECRET_KEY: str = secrets.token_urlsafe(32)
    # 60 minutes * 24 hours * 8 days = 8 days
    ACCESS_TOKEN_EXPIRE_MINUTES: int = 60 * 24 * 8
    FRONTEND_HOST: str = "http://localhost:5173"
    ENVIRONMENT: Literal["local", "staging", "production"] = "local"

    BACKEND_CORS_ORIGINS: Annotated[
        list[AnyUrl] | str, BeforeValidator(parse_cors)
    ] = []

    @computed_field  # type: ignore[prop-decorator]
    @property
    def all_cors_origins(self) -> list[str]:
        return [str(origin).rstrip("/") for origin in self.BACKEND_CORS_ORIGINS] + [
            self.FRONTEND_HOST
        ]

    PROJECT_NAME: str
    SENTRY_DSN: HttpUrl | None = None
    POSTGRES_SERVER: str
    POSTGRES_PORT: int = 5432
    POSTGRES_USER: str
    POSTGRES_PASSWORD: str = ""
    POSTGRES_DB: str = ""

    @computed_field  # type: ignore[prop-decorator]
    @property
    def SQLALCHEMY_DATABASE_URI(self) -> PostgresDsn:
        return MultiHostUrl.build(
            scheme="postgresql+psycopg",
            username=self.POSTGRES_USER,
            password=self.POSTGRES_PASSWORD,
            host=self.POSTGRES_SERVER,
            port=self.POSTGRES_PORT,
            path=self.POSTGRES_DB,
        )

    SMTP_TLS: bool = True
    SMTP_SSL: bool = False
    SMTP_PORT: int = 587
    SMTP_HOST: str | None = None
    SMTP_USER: str | None = None
    SMTP_PASSWORD: str | None = None
    # TODO: update type to EmailStr when sqlmodel supports it
    EMAILS_FROM_EMAIL: str | None = None
    EMAILS_FROM_NAME: str | None = None

    @model_validator(mode="after")
    def _set_default_emails_from(self) -> Self:
        if not self.EMAILS_FROM_NAME:
            self.EMAILS_FROM_NAME = self.PROJECT_NAME
        return self

    EMAIL_RESET_TOKEN_EXPIRE_HOURS: int = 48

    @computed_field  # type: ignore[prop-decorator]
    @property
    def emails_enabled(self) -> bool:
        return bool(self.SMTP_HOST and self.EMAILS_FROM_EMAIL)

    # TODO: update type to EmailStr when sqlmodel supports it
    EMAIL_TEST_USER: str = "test@example.com"
    # TODO: update type to EmailStr when sqlmodel supports it
    FIRST_SUPERUSER: str
    FIRST_SUPERUSER_PASSWORD: str

    def _check_default_secret(self, var_name: str, value: str | None) -> None:
        if value == "changethis":
            message = (
                f'The value of {var_name} is "changethis", '
                "for security, please change it, at least for deployments."
            )
            if self.ENVIRONMENT == "local":
                warnings.warn(message, stacklevel=1)
            else:
                raise ValueError(message)

    @model_validator(mode="after")
    def _enforce_non_default_secrets(self) -> Self:
        self._check_default_secret("SECRET_KEY", self.SECRET_KEY)
        self._check_default_secret("POSTGRES_PASSWORD", self.POSTGRES_PASSWORD)
        self._check_default_secret(
            "FIRST_SUPERUSER_PASSWORD", self.FIRST_SUPERUSER_PASSWORD
        )

        return self


settings = Settings()  # type: ignore

 

 

 

dynaconf

https://www.dynaconf.com/#reading-settings-from-files

Features¶

• Inspired by the 12-factor application guide
• Settings management (default values, validation, parsing, templating)
• Protection of sensitive information (passwords/tokens)
• Multiple file formats toml|yaml|json|ini|py and also customizable loaders.
• Full support for environment variables to override existing settings (dotenv support included).
• Optional layered system for multi environments [default, development, testing, production] (also called multi profiles)
• Built-in support for Hashicorp Vault and Redis as settings and secrets storage.
• Built-in extensions for Django and Flask web frameworks.
• CLI for common operations such as init, list, write, validate, export.