envarify 1.1.3

Environment variables parsing and validation using python type hints

Envarify

Environment variables parsing and validation using python type hints

Usage

Having some environment variables:

export TIMEOUT_S=2.5
export API_KEY=some_key
export ALLOWED_IDS=1,2,3
export ENABLE_FEATURE=true

We can create a config object in Python:

from envarify import BaseConfig, EnvVar

class MyConfig(BaseConfig):
    timeout_s: float = EnvVar("TIMEOUT_S")
    api_key: str = EnvVar("API_KEY")
    allowed_ids: set[int] = EnvVar("ALLOWED_IDS")
    enable_feature: bool = EnvVar("ENABLE_FEATURE", default=False)
    optional_arg: str | None = EnvVar("OPTIONAL_ARG", default=None)

config = MyConfig.fromenv()
print(config)
#> MyConfig(timeout_s=2.5, api_key="some_key", allowed_ids={1,2,3}, enable_feature=True, optional_arg=None)

Missing environment variables

If there are some required environment variables that are not set, error will be raised:

config = MyConfig.fromenv()
#> MissingEnvVarsError: TIMEOUT_S, API_KEY, ALLOWED_IDS

Testing

In tests for your application you don't have to worry about mocking the environment variables. Instead just create a mock config object:

mock_config = MyConfig(timeout_s=4.2, api_key="dummy", allowed_ids={1,2,3}, enable_feature=True)

Supported Types

• Primitive types

  • int
  • float
  • bool
  • str

• Dictionary

  dict type reads environmental variable as JSON

• Sequences (delimiter separated values)

  • list[T]

  • set[T]

  • tuple[T]

    where T is any primitive type

• BaseConfig subtype itself

  With environment variables COMPONENT_TIMEOUT=5 and OTHER=dummy you can do:

  from envarify import BaseConfig, EnvVar
  
  class ComponentConfig(BaseConfig):
      timeout: int = EnvVar("COMPONENT_TIMEOUT")
  
  class ApplicationConfig(BaseConfig):
      component: ComponentConfig
      other: str = EnvVar("OTHER")
  
  config = ApplicationConfig.fromenv()
  print(config)
  #> ApplicationConfig(component=ComponentConfig(timeout=5), other='dummy')