zero-config 0.1.1

A zero-configuration library with smart environment variable support and type-aware defaults

Zero Config 🚀

Smart configuration management with layered overrides and type-aware defaults.

🎯 Core Concept

Zero Config provides layered configuration where each layer can override the previous one:

1. Application Defaults → 2. Environment Variables → 3. Environment Files

from zero_config import setup_environment, get_config

# 1. Define application defaults
default_config = {
    'openai_api_key': '',           # Will be overridden by env var
    'llm.temperature': 0.0,         # Will be overridden by .env file
    'database.host': 'localhost',   # Will stay as default
}

# 2. Set environment variable
# export OPENAI_API_KEY="sk-your-key-here"

# 3. Create .env.zero_config file
# llm.temperature=0.7
# database.port=5432

setup_environment(default_config=default_config)
config = get_config()

# Final configuration:
print(config.get('openai_api_key'))    # "sk-your-key-here" (from env var)
print(config.get('llm.temperature'))   # 0.7 (from .env file, converted to float)
print(config.get('database.host'))     # "localhost" (from defaults)
print(config.get('database.port'))     # 5432 (from .env file, new key as int)

🏗️ Why Layered Configuration?

• Defaults in Code: Your app defines the schema and sensible defaults
• Environment Variables: Perfect for deployment-specific overrides (Docker, CI/CD)
• Environment Files: Great for local development and secrets management
• Type Safety: Environment strings are automatically converted to match your default types

🔧 Configuration Sources

Environment Variables

# Uppercase env vars automatically override config keys
export OPENAI_API_KEY="sk-your-key-here"    # Becomes: openai_api_key
export DEBUG="true"                         # Becomes: debug (bool)
export MODELS='["gpt-4", "claude-3"]'       # JSON arrays for lists
export DATABASE_URL="host1,host2,host3"     # Strings with commas stay safe

# Section headers with double underscore
export LLM__TEMPERATURE="0.7"               # Becomes: llm.temperature
export DATABASE__HOST="remote.db.com"       # Becomes: database.host

Environment Files

# .env.zero_config (default) or custom files
openai_api_key=sk-your-local-key
llm.temperature=0.7
database.port=5432
models=["gpt-4", "claude-3"]

Custom Environment Files

setup_environment(
    default_config=default_config,
    env_files="config/production.env"          # Single file
)

setup_environment(
    default_config=default_config,
    env_files=["base.env", "production.env"]   # Multiple files (later wins)
)

📁 Project Root Detection

Critical: Environment files are loaded relative to your project root.

# Auto-detection (looks for .git, pyproject.toml, setup.py, etc.)
setup_environment(default_config=config)

# Override via environment variable
# export PROJECT_ROOT="/path/to/project"
setup_environment(default_config=config)

Why it matters: Zero Config needs to know your project root to:

• Load .env.zero_config from the correct location
• Resolve relative paths in env_files parameter
• Provide accurate dynamic path helpers (config.data_path(), etc.)

🛠️ Advanced Features

Dynamic Path Helpers

config = get_config()

# Any directory name + '_path' works (Ruby on Rails style)
config.data_path('database.db')      # /project/data/database.db
config.logs_path('app.log')          # /project/logs/app.log
config.cache_path('session.json')    # /project/cache/session.json
config.models_path('gpt4.bin')       # /project/models/gpt4.bin

Section Configuration

# Define sections with dot notation
default_config = {
    'llm.models': ['gpt-4'],
    'llm.temperature': 0.0,
    'database.host': 'localhost',
    'database.port': 5432,
}

config = get_config()
llm_config = config.get('llm')      # {'models': [...], 'temperature': 0.0}
db_config = config.get('database')  # {'host': 'localhost', 'port': 5432}

Type Conversion

Environment variables are automatically converted to match your default types:

• Numbers: "8000" → 8000 (int), "0.7" → 0.7 (float)
• Booleans: "true" → True, "false" → False
• Lists: '["a","b"]' → ['a','b'] (JSON only - comma strings stay safe)
• Strings: Always preserved as-is (safe for URLs, CSVs, etc.)

📦 Installation

pip install zero-config

🔗 API Reference

# Setup
setup_environment(
    default_config={...},           # Your app's defaults
    env_files="custom.env"          # Optional: custom env file(s)
)

# Access
config = get_config()
config.get('key', default)         # Safe access with fallback
config['key']                      # Direct access (raises KeyError if missing)
config.get('llm')                 # Get all llm.* keys as dict
config.to_dict()                   # Get all config as dict

# Dynamic paths (Ruby on Rails style)
config.data_path('file.db')        # /project/data/file.db
config.logs_path('app.log')        # /project/logs/app.log
config.any_name_path('file')       # /project/any_name/file