environ-config: Application Configuration With Env Variables

environ-config allows you to configure your applications using environment variables – as recommended in The Twelve-Factor App methodology – with elegant, boilerplate-free, and declarative code:

>>> import environ
>>> # Extracts secrets from Vault-via-envconsul: 'secret/your-app':
>>> vault = environ.secrets.VaultEnvSecrets(vault_prefix="SECRET_YOUR_APP")
>>> @environ.config(prefix="APP")
... class AppConfig:
...    @environ.config
...    class DB:
...        name = environ.var("default_db")
...        host = environ.var("default.host")
...        port = environ.var(5432, converter=int)  # Use attrs's converters and validators!
...        user = environ.var("default_user")
...        password = vault.secret()
...
...    env = environ.var()
...    lang = environ.var(name="LANG")  # It's possible to overwrite the names of variables.
...    db = environ.group(DB)
...    awesome = environ.bool_var()
>>> cfg = environ.to_config(
...     AppConfig,
...     environ={
...         "APP_ENV": "dev",
...         "APP_DB_HOST": "localhost",
...         "LANG": "C",
...         "APP_AWESOME": "yes",  # true and 1 work too, everything else is False
...         # Vault-via-envconsul-style var name:
...         "SECRET_YOUR_APP_DB_PASSWORD": "s3kr3t",
... })  # Uses os.environ by default.
>>> cfg
AppConfig(env='dev', lang='C', db=AppConfig.DB(name='default_db', host='localhost', port=5432, user='default_user', password=<SECRET>), awesome=True)
>>> cfg.db.password
's3kr3t'

AppConfig.from_environ({...}) is equivalent to the code above, depending on your taste.

Features

• Declarative & boilerplate-free.

• Nested configuration from flat environment variable names.

• Default & mandatory values: enforce configuration structure without writing a line of code.

• Built on top of attrs which gives you data validation and conversion for free.

• Pluggable secrets extraction. Ships with:

  • HashiCorp Vault support via envconsul.
  • AWS Secrets Manager (needs boto3)
  • INI files, because secrets in env variables are icky.

• Helpful debug logging that will tell you which variables are present and what environ-config is looking for.

• Built-in dynamic help documentation generation.

You can find the full documentation including a step-by-step tutorial on Read the Docs.

Project Information

environ-config is maintained by Hynek Schlawack and is released under the Apache License 2.0 license. It targets Python 3.7 and newer, and PyPy. Development takes place on GitHub.

The development is kindly supported by Variomedia AG.

environ-config wouldn't be possible without the attrs project.

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