YAML Config

0.1.5 · active · verified Sat Apr 11

Python client for reading YAML based config files. It provides a `Config` class for retrieving configuration variables from YAML files. It allows configuration of root and directory paths via environment variables. The library is currently at version 0.1.5 and has a low-cadence release cycle, with the last PyPI release in June 2020.

Warnings

breaking Older versions of `yaml-config` (prior to 0.1.3) might have used `PyYAML`'s `yaml.load()` function without explicitly specifying a `Loader` parameter. This usage is considered unsafe and was deprecated in `PyYAML` 5.1+, leading to a `TypeError` in `PyYAML` 6.0+.
Fix: Upgrade to `yaml-config` version 0.1.3 or higher, which internally defaults to `yaml.SafeLoader` to mitigate this issue. If direct `PyYAML` interaction in your application is necessary and upgrade is not possible, explicitly pass `Loader=yaml.SafeLoader` to `yaml.load()` to prevent errors and enhance security.
gotcha The `yaml-config` library supports configuring root and directory paths for config files using environment variables (e.g., `<prefix>_CONFIG_ROOT`, `<prefix>_CONFIG_DIR`). However, it does not natively provide functionality for interpolating environment variables *within* the YAML file content itself (e.g., `api_key: ${API_KEY}`).
Fix: If you require environment variable interpolation for values inside your YAML content, consider pre-processing your YAML files (e.g., using Python's `os.path.expandvars` on the file content before passing it to `yaml-config`) or explore alternative YAML libraries that explicitly support this feature.
gotcha Using `yaml.load()` directly from `PyYAML` without specifying a safe loader (like `yaml.SafeLoader` or `yaml.FullLoader`) is a known security vulnerability, as it can execute arbitrary Python code. Although `yaml-config` versions 0.1.3+ default to `yaml.SafeLoader` for its internal loading, direct interactions with `PyYAML` in your own code should always prioritize safety.
Fix: Always use `yaml.safe_load()` or explicitly pass `Loader=yaml.SafeLoader` when loading YAML from untrusted sources, even if `yaml-config` handles its internal loading safely.

Install

pip install yaml-config Install with pip

Imports

Config
```
from yaml_config import Config
```
The primary class for loading and managing YAML configurations. It is recommended to subclass this class.

Quickstart

This quickstart demonstrates how to create a `Config` subclass to load a YAML file and access its properties. It shows how to define a `default_file` and access nested configurations.

import os
from yaml_config import Config

# Create a dummy config file for the example
config_content = """
database:
  host: localhost
  port: 5432
logging:
  level: INFO
"""
with open("my_app_config.yaml", "w") as f:
    f.write(config_content)

# You can optionally set environment variables to define config root/dir
# For example, in your shell: export MYAPP_CONFIG_ROOT=/tmp
# This example assumes the file is in the current working directory.

class MyAppConfig(Config):
    # Define the default config file name to be loaded
    default_file = 'my_app_config.yaml'
    # If using environment variables for root/dir, define a prefix:
    # default_env_prefix = 'MYAPP' # Would look for MYAPP_CONFIG_ROOT / MYAPP_CONFIG_DIR

# Load the configuration
config = MyAppConfig()

# Access configuration values
print(f"Database Host: {config.database.host}")
print(f"Database Port: {config.database.port}")
print(f"Logging Level: {config.logging.level}")

# Clean up dummy config file
os.remove("my_app_config.yaml")

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