onion-config 3.0.0

onion_config is a Python package that allows for easy configuration management. It allows for loading and validating configuration data from environment variables and config files in JSON and YAML formats.

onion_config

onion_config is a Python package that allows for easy configuration management. It allows for loading and validating configuration data from environment variables and config files in JSON and YAML formats.

Pydantic based custom config package for python projects.

Features

• Main config based on Pydantic schema - https://pypi.org/project/pydantic
• Load environment variables - https://pypi.org/project/python-dotenv
• Load configs from YAML and JSON files
• Update the default config with additional configurations (extra_configs directory)
• Pre-load hook function to modify config data before loading and validation
• Validate config values with Pydantic validators
• Config as dictionary or Pydantic model (with type hints)
• Pre-defined base config schema for common config (BaseConfig)
• Base for custom config loader (ConfigLoader)

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Installation

1. Prerequisites

• Python (>= v3.7)
• PyPi (>= v21)

2. Install onion-config package

Choose one of the following methods to install the package [A ~ F]:

A. [RECOMMENDED] Install from PyPi

# Install or upgrade package:
pip install -U onion-config

B. Install latest version from GitHub

# Install package by git:
pip install git+https://github.com/bybatkhuu/mod.python-config.git

C. Install from pre-built release files

1. Download .whl or .tar.gz file from releases - https://github.com/bybatkhuu/mod.python-config/releases
2. Install with pip:

# Install from .whl file:
pip install ./onion_config-[VERSION]-py3-none-any.whl
# Or install from .tar.gz file:
pip install ./onion_config-[VERSION].tar.gz

D. Install from source code by building package

# Clone repository by git:
git clone https://github.com/bybatkhuu/mod.python-config.git onion_config
cd ./onion_config

# Install python build tool:
pip install -U pip build

# Build python package:
python -m build

_VERSION=$(./scripts/get-version.sh)

# Install from .whl file:
pip install ./dist/onion_config-${_VERSION}-py3-none-any.whl
# Or install from .tar.gz file:
pip install ./dist/onion_config-${_VERSION}.tar.gz

E. Install with pip editable development mode (from source code)

# Clone repository by git:
git clone https://github.com/bybatkhuu/mod.python-config.git onion_config
cd ./onion_config

# Install with editable development mode:
pip install -e .

F. Manually add to PYTHONPATH (not recommended)

# Clone repository by git:
git clone https://github.com/bybatkhuu/mod.python-config.git onion_config
cd ./onion_config

# Install python dependencies:
pip install -r ./requirements.txt

# Add current path to PYTHONPATH:
export PYTHONPATH="${PWD}:${PYTHONPATH}"

Usage/Examples

Simple

To use onion_config, import the ConfigLoader class from the package:

from onion_config import ConfigLoader

You can then create an instance of ConfigLoader:

config_loader = ConfigLoader(auto_load=True)

This will automatically load configuration data from environment variables and config files located in the default directory ('./configs'). The configuration data can then be accessed via the config property of the ConfigLoader instance:

config = config_loader.config

Advanced

configs/config.yml:

env: production

app:
  name: "My App"
  bind_host: "0.0.0.0"
  version: "0.0.1"
  ignore_val: "Ignore me"

logger:
  output: "stdout"

configs/logger.json:

{
    "logger":
    {
        "level": "info",
        "output": "file"
    }
}

.env:

ENV=development

DEBUG=true

APP_NAME="New App"
APP_SECRET="my_secret"

main.py:

import sys
import pprint
import logging
from enum import Enum
from typing import Union

from pydantic import Field, SecretStr
from pydantic_settings import SettingsConfigDict

from onion_config import ConfigLoader, BaseConfig


logging.basicConfig(stream=sys.stdout, level=logging.INFO)
logger = logging.getLogger(__name__)


# Pre-load function to modify config data before loading and validation:
def _pre_load_hook(config_data: dict) -> dict:
    config_data["app"]["port"] = "80"
    config_data["extra_val"] = "Something extra!"

    return config_data

# Environments as Enum:
class EnvEnum(str, Enum):
    LOCAL = "local"
    DEVELOPMENT = "development"
    TEST = "test"
    STAGING = "staging"
    PRODUCTION = "production"

# App config schema:
class AppConfig(BaseConfig):
    name: str = Field("App", min_length=2, max_length=32)
    bind_host: str = Field("localhost", min_length=2, max_length=128)
    port: int = Field(8000, ge=80, lt=65536)
    secret: SecretStr = Field(..., min_length=8, max_length=64)
    version: str = Field(..., min_length=5, max_length=16)
    description: Union[str, None] = Field(None, min_length=4, max_length=64)

    model_config = SettingsConfigDict(extra="ignore", env_prefix="APP_")

# Main config schema:
class ConfigSchema(BaseConfig):
    env: EnvEnum = Field(EnvEnum.LOCAL)
    debug: bool = Field(False)
    app: AppConfig = Field(...)


if __name__ == "__main__":
    try:
        # Main 'config' object for usage:
        config: ConfigSchema = ConfigLoader(
            config_schema=ConfigSchema, pre_load_hook=_pre_load_hook
        ).load()
    except Exception:
        logger.exception("Failed to load config:")
        exit(2)

    logger.info(f" ENV: {config.env}")
    logger.info(f" DEBUG: {config.debug}")
    logger.info(f" Extra: {config.extra_val}")
    logger.info(f" Logger: {config.logger}")
    logger.info(f" App: {config.app}")
    logger.info(f" Secret: '{config.app.secret.get_secret_value()}'\n")
    logger.info(f" Config:\n{pprint.pformat(config.model_dump())}\n")

    try:
        # This will raise ValidationError
        config.app.port = 8443
    except Exception as e:
        logger.error(f" {e}\n")

Run the example:

cd ./examples

python ./main.py

Output:

INFO:__main__: ENV: development
INFO:__main__: DEBUG: True
INFO:__main__: Extra: Something extra!
INFO:__main__: Logger: {'level': 'info', 'output': 'stdout'}
INFO:__main__: App: name='New App' bind_host='0.0.0.0' port=80 secret=SecretStr('**********') version='0.0.1' description=None
INFO:__main__: Secret: 'my_secret'

INFO:__main__: Config:
{'app': {'bind_host': '0.0.0.0',
         'description': None,
         'name': 'New App',
         'port': 80,
         'secret': SecretStr('**********'),
         'version': '0.0.1'},
 'debug': True,
 'env': <EnvEnum.DEVELOPMENT: 'development'>,
 'extra_val': 'Something extra!',
 'logger': {'level': 'info', 'output': 'stdout'}}

ERROR:__main__: 1 validation error for AppConfig
port
  Instance is frozen [type=frozen_instance, input_value=8443, input_type=int]

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Running Tests

To run tests, run the following command:

# Install python development dependencies:
pip install -r ./requirements.dev.txt

# Run tests:
python -m pytest -sv

FAQ

What is the order of loading config?

Load order:

1. Load environment variables from .env file.
2. Check required environment variables are exist or not.
3. Load config files from configs_dir into config_data.
4. Load extra config files from extra_configs_dir into config_data.
5. Execute pre_load_hook method to modify config_data.
6. Init config_schema with config_data into final config.

Environment Variables

You can use the following environment variables inside .env.example file:

ONION_CONFIG_EXTRA_DIR="./extra_configs_dir"

Documentation

• docs
• scripts

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References

• https://docs.pydantic.dev
• https://github.com/pydantic/pydantic
• https://saurabh-kumar.com/python-dotenv
• https://github.com/theskumar/python-dotenv
• https://packaging.python.org/tutorials/packaging-projects