---
id: yacman
version: "1.0.0"
license: BSD-2-Clause
license_treatment: permissive
maintenance: active
---

# yacman — A YAML configuration manager

License: permissive · Maintenance: active · Downloads: 213.4K/mo

## What it is and what it does

Yacman is a YAML configuration manager that wraps pyyaml and ubiquerg to provide a higher-level interface for loading, modifying, and persisting YAML configuration files. It exposes configuration data as a dictionary-like object with support for nested access, environment variable expansion via the `.exp` attribute, and conversion to/from Python objects and YAML strings.

The package's main feature is file-safe concurrent access through separate read and write locks, allowing multiple processes to read a configuration simultaneously while ensuring writes are serialized and can rebase against disk changes. Version 1.0.0 introduced explicit constructor functions (from_yaml_file, from_yaml_data, from_obj) and separated locking into read_lock and write_lock context managers, replacing the earlier unified lock pattern. It targets Python 3.10+ and is actively maintained.

Use it for:

- Load and access nested YAML configuration files in a Python application with dictionary-like syntax.
- Safely update YAML config files from multiple processes using write_lock to prevent concurrent writes and data loss.
- Expand environment variables in YAML values using the `.exp` accessor for dynamic configuration.
- Convert between YAML files, Python dictionaries, and YAML strings for configuration serialization.
- Rebase in-memory configuration against disk changes when other processes may have modified the file.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Yacman provides a Python interface for reading, writing, and managing YAML configuration files with support for file locking, environment variable expansion, and multi-process safe updates.

Yes. Yacman is a lightweight, actively maintained configuration manager with low install friction, permissive licensing, and no known vulnerabilities. Install it if you need file-safe concurrent YAML access with environment variable expansion; skip it if you only need basic YAML parsing without multi-process locking.

## Install

pip install yacman
uv add yacman
poetry add yacman

## Installing yacman

Before you install: Low install friction with only two runtime dependencies (pyyaml and ubiquerg). Actively maintained with a recent release (161 days ago) and ongoing repository activity.

License in practice: BSD-2-Clause is a permissive license allowing commercial and private use with minimal restrictions; you may use this package freely in most projects.

Quickstart:

from yacman import YAMLConfigManager, write_lock, read_lock

data = {"my_list": [1,2,3], "my_int": 8}
ym = YAMLConfigManager.from_obj(data)
print(ym["my_int"])

with write_lock(ym) as locked_ym:
    locked_ym.rebase_and_write()

Requires Python 3.10 or later. File-based locking is not re-entrant; do not nest lock contexts on the same file or deadlock will occur.

Verify before relying:

- Whether ubiquerg dependency is a utility library or introduces significant transitive dependencies.
- Performance characteristics when handling large YAML files or frequent concurrent access patterns.

## Package facts

- License: BSD-2-Clause (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 213.4K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

yaml configuration manager, yaml config file handling, yaml file locking, configuration management python, yaml environment variable expansion, yaml read write lock, yaml config updates, yaml-config, file-locking, multi-process

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