petri 0.23.1

Free your python code from 12-factor boilerplate.

petri: free your python code from 12-factor boilerplate.

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Summary

Importing petri equips your app/pacakage with:

• Dotenv file handling using python-dotenv.

• Package metadata (for installed packages), using importlib_metadata.

• Settings using pydantic.

• Logging config using structlog.

• Environment switching (prod/dev/test) handling via ENV environment variable.

Install

Install using poetry or pip:

• Poetry:

  poetry add petri

• pip:

  pip install petri

Usage

• [OPTIONAL] Define an environment variable named env_file, to feed additional envs. Its value must be the path to a valid, existing file.

• Define dev/prod/test settings:

  from petri.settings import BaseSettings
  
  
  class Settings(BaseSettings):
      class Config:  # pylint: disable=missing-docstring,too-few-public-methods
          env_prefix = "A_PKG_"
  
  
  class Production(Settings):
      ENV = "production"
  
  
  class Development(Settings):
      ENV = "development"
  
  
  class Testing(Settings):
      ENV = "testing"

  IMPORTANT: In your base class, define Config.env_prefix. For example, a package named a-pkg turns into A_PKG_. The code used should be compatible with: Config.env_prefix=[package_name].upper().replace(‘-’ ,’_’)+’_’.

• Select which class of setting to use, by doing one of the folowing:

  • Set the envvar [package_name].replace(“-”, “_”).upper() + “_CONFIG” to a defined settings class (eg: A_PKG_CONFIG=a_pkg.settings:Production), or

  • Use the default_config kwarg when instantiating petri.Petri (See Below)

  Of course, you can use both. Petri will attempt to load said env, and if not found, default to the defined kwarg.

• Instantiate petri.Petri form your package’s __init__.py, like so:

  """A package: sample petri usage"""
  
  from petri import Petri
  
  pkg = Petri(__file__)
  
  __version__ = "1.2.3"

This allows petri to:

• Load env_file’s contents, if defined.

• Provide your package’s metadata (version, author, etc), available in pkg.meta (lazy-loaded to avoid reading metadata files unnecessarily).

• Activate and instantiate a settings class, according to environment var and default, available in pkg.settings (https://pydantic-docs.helpmanual.io/#id5)

• Configure and expose a logger, available in pkg.log, which uses configuration defined in your settings.