envyconfig 0.4.0

YAML reader with ENV interpolation.

pyconfig

Python package for YAML config files. Reads a specified YAML file, and returns the corresponding dict structure.

Builds on the PyYAML package, with the following additions:

• Environment variables can be specified as config values.
• GCP Secrets can be specified as config values.
• Nested YAML structures can be flattened to get a simple key / value dict.
• Default values can be specified, for instance from the command line.

Basic Usage

>>> import envyconfig
>>> config = envyconfig.load('config.yaml')
>>> print(config)
{'foo': {'bar': 'baz'}}

Sample config file.

foo:
   # Loads "bar" from secret "my-secret" in the "my-project" GCP project.  Defaults to "otherwise".
   bar: ${gs:/my-project/my-secret:otherwise}
   # Loads "baz" from the environment variable "ENVVAR".  Defaults to "something_else".
   baz: ${env:ENVVAR:something_else}

Usage Details

Interpolation keys.

You indicate the values you want interpolated by one of the configured engines through a wrapper ${<method>:<key>:<default>}, such as ${env:MY_VAR:my_default}. The currently supported engines are

• environment (os.environ) variables (key: env), and
• Google Secret Manager (key: gs). The engines are lazy-loaded, so unless you request interpolation by one of them, the configuration is not loaded. This is useful for advanced engines (presently gs), that rely on external libraries and configuration.

As the method, key and default values are separated by a :, this character is not allowed in the method or key names. It is allowed in default values, though. So $(env:REDIRECT_PAGE:https://localhost/} is legal syntax.

Environment variables

Environment variables behave like you expect them to.

Google Secret Manager

This engine requires the optional dependency (or separate installation of) googlesecrets (ie. pip install envyconfig[googlesecrets]), and a pointer to your GCP key (GOOGLE_APPLICATION_CREDENTIALS) with the appropriate credentials.

Credits and further documentation

• GCP Python Secret Manager
• PyYAML
• EnvyConfig