yi-config-starter 0.2.2

Config starter for my local projects

yi-config-starter

A lightweight YAML configuration loader with automatic config discovery, placeholder substitution, and a thread-safe singleton interface.

This library is intended to centralize configuration loading logic while keeping application code clean and portable across environments.

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Installation

pip install yi-config-starter

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Quick Start

from yi_config_starter import ApplicationConfiguration

cfg = ApplicationConfiguration.get_instance()
config = cfg.get_config()

db_host = cfg.get_config_value("db.datasource.config.host")
print(db_host)

You may also initialize it explicitly (still resolves to a singleton internally):

from yi_config_starter import ApplicationConfiguration
cfg = ApplicationConfiguration(
    filename="config.yml",
    env_var="MY_APP_CONFIG",
    app_name="my-app",
    # path="/absolute/or/~/path/to/config.yml",
    # extra_placeholders={"PROJECT_ROOT": "/some/path"},
)

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Configuration File Discovery

By default, the loader searches for config.yml in the following order:

1. Explicit path passed to the constructor (path=...)

2. Path provided via environment variable

3. Current working directory, then parent directories (walking upward)

4. User configuration directory

   • Windows: %APPDATA%\<app_name>\config.yml
   • Linux/macOS: ~/.config/<app_name>/config.yml

5. Entries on sys.path (recursive search)

If no configuration file is found, a FileNotFoundError is raised.

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Placeholder Substitution

Before parsing YAML, placeholders in the configuration file are substituted.

Built-in Placeholders

Placeholder	Description
{{HOME}}	User home directory
{{separator}}	OS path separator (/ or \\)
{{APPDATA}}	Windows %APPDATA% or fallback to ~/.config
{{XDG_CONFIG}}	$XDG_CONFIG_HOME or ~/.config
{{ENV:VAR_NAME}}	Value of environment variable VAR_NAME (case-insensitive: ENV/env; if missing, it is reported in the unresolved placeholder error)

Custom placeholders may be supplied via extra_placeholders.

Unresolved placeholders

After preprocessing, if any {{...}} placeholders remain unresolved, a ValueError is raised listing all unresolved placeholder names.

Example

paths:
  data_dir: "{{HOME}}{{separator}}data"
  cache_dir: "{{XDG_CONFIG}}{{separator}}my-app{{separator}}cache"
  # ENV token is case-insensitive, so {{env:...}} also works:
  api_key: "{{env:MY_API_KEY}}"

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API Reference

ApplicationConfiguration.get_instance(...)

Returns the singleton configuration instance (thread-safe).

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cfg.get_config() -> dict

Returns the entire configuration as a dictionary.

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cfg.get_config_value("a.b.c")

Returns a nested configuration value using dot-separated keys.

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ApplicationConfiguration.get_value_from_config(config: dict, key: str)

Static helper for retrieving nested values from an arbitrary dictionary.

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Versioning

The package version is resolved dynamically from:

import yi_config_starter
yi_config_starter.__version__

Defined in:

/yi_config_starter/__init__.py

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License

MIT License — see the LICENSE file.