confeasy 0.0.1

Application configuration inspired by Microsoft.Extensions.Configuration (.NET).

confeasy

Application configuration inspired by Microsoft.Extensions.Configuration (.NET).

The main idea is to have the following workflow:

1. Define one or more configuration sources from where the actual configuration is created (or downloaded).
2. Build the configuration. This basically means put everything into a big flat dictionary where lastly defined sources could override values from previous ones if they match on the configuration key.
3. Use resulting configuration: a. Directly, picking up individual values by their key. b. Bind all or portion of the configuration to a strongly typed class instance (typically a dataclass) and use this instance instead of the configuration itself. The benefit is better intellisense in IDEs and more decoupling.

Getting started

Install the package.

poetry add confeasy
# or similar command for your package manager of choice

In python, usually around application start:

# DbOptions class is an illustrative example of strongly typed configuration.
class DbOptions:
    def __init__(self):
        self.connnection_string: str = ""
        self.max_connections: int = 100

from confeasy import Builder
from confeasy.jsonfile import JsonFile
from confeasy.envars import EnvironmentVariables
from confeasy.cmdline import CommandLine

# Order of the configuration sources matters; later sources can overwrite values from earlier ones.
builder = (Builder()
           .add_source(JsonFile()
                       .required("settings.json")
                       .optional("setting.local.json"))
           .add_source(EnvironmentVariables(prefix="MYAPP_"))
           .add_source(CommandLine()))

config = builder.build()

# Bind configuration to a class instance and pass the instance to other objects.
options = config.bind(DbOptions(), prefix="db")

# OR pick up individual values:
db_conn_str = config.get_value("db.connection_string")

Out-of-the-box configuration sources

• JSON files
• command line arguments
• environment variables

Additional configuration sources

• confeasy.azure_appc - using Azure AppConfiguration service; PyPI | source

Development

For developer related information, check Developer Guide.

Near future:

• Support for TOML files using tomllib from standard library.

Never:

• YAML files will not be supported unless a parsing module is available in the standard library.
• INI files will not be supported, as they are not well-suited for handling hierarchical structures that application configuration often evolve towards.