environs

一、说明

Environs是解析环境变量的Python库。它的开发受envparse启发，底层使用marshmallow验证并序列化值。

environs 主要要实现三个目标：
1. 让扩展解析行为和编写插件变的容易。
2. 把序列化和验证的工作交给marshmallow去做。
3. 清除冗余的 API.

二、安装

pip install environs

三、基本用法

from environs import Env

env = Env()
env.read_env()  # read .env file, if it exists
# required variables
gh_user = env("GITHUB_USER")  # => 'sloria'
secret = env("SECRET")  # => raises error if not set

# casting
max_connections = env.int("MAX_CONNECTIONS")  # => 100
ship_date = env.date("SHIP_DATE")  # => datetime.date(1984, 6, 25)
ttl = env.timedelta("TTL")  # => datetime.timedelta(0, 42)
log_level = env.log_level("LOG_LEVEL")  # => logging.DEBUG

# providing a default value
enable_login = env.bool("ENABLE_LOGIN", False)  # => True
enable_feature_x = env.bool("ENABLE_FEATURE_X", False)  # => False

# parsing lists
gh_repos = env.list("GITHUB_REPOS")  # => ['webargs', 'konch', 'ped']
coords = env.list("COORDINATES", subcast=float)  # => [23.3, 50.0]

四、支持的类型

env.str
env.bool
env.int
env.float
env.decimal
env.list (accepts optional subcast keyword argument)
env.dict (accepts optional subcast keyword argument)
env.json
env.datetime
env.date
env.timedelta (assumes value is an integer in seconds)
env.url
env.uuid
env.log_level
env.path (casts to a pathlib.Path)

五、Flask 项目使用

# myapp/settings.py

from environs import Env

env = Env()
env.read_env()

# Override in .env for local development
DEBUG = env.bool("FLASK_DEBUG", default=False)
# SECRET_KEY is required
SECRET_KEY = env.str("SECRET_KEY")

六、定义环境变量

import platform
from os.path import dirname, abspath, join
from environs import Env
from loguru import logger
  
env = Env()
env.read_env()
  
# definition of flags
IS_WINDOWS = platform.system().lower() == 'windows'
  
# definition of dirs
ROOT_DIR = dirname(dirname(abspath(__file__)))
LOG_DIR = join(ROOT_DIR, env.str('LOG_DIR', 'logs'))
  
# definition of environments
DEV_MODE, TEST_MODE, PROD_MODE = 'dev', 'test', 'prod'
APP_ENV = env.str('APP_ENV', DEV_MODE).lower()
APP_DEBUG = env.bool('APP_DEBUG', True if APP_ENV == DEV_MODE else False)
APP_DEV = IS_DEV = APP_ENV == DEV_MODE
APP_PROD = IS_PROD = APP_DEV == PROD_MODE
APP_TEST = IS_TEST = APP_ENV = TEST_MODE
  
# redis host
REDIS_HOST = env.str('REDIS_HOST', '127.0.0.1')
# redis port
REDIS_PORT = env.int('REDIS_PORT', 6379)
# redis password, if no password, set it to None
REDIS_PASSWORD = env.str('REDIS_PASSWORD', None)
# redis connection string, like redis://[password]@host:port or rediss://[password]@host:port
REDIS_CONNECTION_STRING = env.str('REDIS_CONNECTION_STRING', None)
  
# definition of api
API_HOST = env.str('API_HOST', '0.0.0.0')
API_PORT = env.int('API_PORT', 5555)
API_THREADED = env.bool('API_THREADED', True)
  
# definition of flags
ENABLE_TESTER = env.bool('ENABLE_TESTER', True)
ENABLE_GETTER = env.bool('ENABLE_GETTER', True)
ENABLE_SERVER = env.bool('ENABLE_SERVER', True)
  
# logger
logger.add(env.str('LOG_RUNTIME_FILE', 'runtime.log'), level='DEBUG', rotation='1 week', retention='20 days')
logger.add(env.str('LOG_ERROR_FILE', 'error.log'), level='ERROR', rotation='1 week')

九、参考文档

https://www.cnpython.com/pypi/environs

https://pypi.org/project/environs/

https://blog.csdn.net/handsomekang/article/details/78682575

https://github.com/Python3WebSpider/ProxyPool

https://django-environ.readthedocs.io/en/latest/

https://www.joyk.com/dig/detail/1533835838794571