Features

This chapter covers the core features and capabilities of Config Manager.

Features

• Layered merge — Defaults < config file < environment variables < CLI overrides, with deep recursive merging
• Multiple file formats — JSON, INI, and .env files supported out of the box
• Dot-path access — Get and set nested values with database.host notation
• Schema validation — Validate types, required keys, allowed values, numeric ranges, and regex patterns
• Type coercion — Automatic and explicit conversion between str, int, float, bool, and list types
• Secret masking — Export configs with passwords, tokens, and API keys automatically redacted
• Config diff — Compare two config files side-by-side with added/removed/changed reporting
• Environment variable overlay — Map CFG_DATABASE__HOST to database.host automatically

Requirements

• Python 3.10+
• No external dependencies (stdlib only)

Quick Start

Follow this guide to get Config Manager up and running in your environment.

Quick Start

# Get a single value by dot-path
python src/config_manager.py --config examples/config_manager_config.json --get database.host

# Set an override and see the result
python src/config_manager.py --config examples/config_manager_config.json --set database.port=3306

# Validate config against a schema
python src/config_manager.py --config examples/config_manager_config.json --validate --schema examples/schema.json

# Export the full merged config (secrets masked)
python src/config_manager.py --config examples/config_manager_config.json --export

# List all dot-path keys
python src/config_manager.py --config examples/config_manager_config.json --keys

# Diff two config files
python src/config_manager.py --config examples/config_manager_config.json --diff examples/schema.json

Configuration Reference

CLI Options

Schema Format

Schemas define expected types, required fields, allowed values, and constraints:

{
    "properties": {
        "database": {
            "type": "object",
            "required": true,
            "properties": {
                "host": {"type": "string", "required": true},
                "port": {"type": "integer", "min": 1, "max": 65535},
                "name": {"type": "string", "allowed": ["prod_db", "dev_db"]}
            }
        }
    }
}

Supported field-level keys: type, required, allowed, min, max, pattern, default.

Environment Variable Mapping

Set CFG_-prefixed variables to override config at runtime. Double underscore (__) denotes nesting:

export CFG_DATABASE__HOST=prod-db.example.com
export CFG_DATABASE__PORT=5432
export CFG_APP__DEBUG=true

These map to database.host, database.port, and app.debug respectively.