environ-config: Application Configuration With Env Variables

environ-config allows you to load your application's configuration from 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. Development takes place on GitHub.

The development is kindly supported by Variomedia AG and all my amazing GitHub Sponsors.

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

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Release Information

Removed

• Support for Python 3.8 and 3.9. #134

• Support for attrs older than 21.3.0 (the one that introduced the attrs namespace). #134

Added

• Support for Python 3.14 and 3.15. #134

Changed

• environ-config now uses @attrs.define et al instead of @attr.s to help with typing support. This should not make any difference in practice, but people doing weird things (I know y'all are out there!) might run into paper cuts. #134

• Secrets are now handled like environment variables in optional groups, so that if all secrets (and environment variables) are missing, the group becomes None. This change also causes the MissingSecretError exceptions to include all missing secrets, not just the first one. #100

Fixed

• Type hints for environ.group() now respects the optional argument. #98

Full Changelog →