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Getting Started

Installation

pip install qools

For local development:

git clone https://github.com/qarium/qools.git
cd qools
pip install -e ".[test,docs]"

First Steps

The main module is funcutils, imported in submodule style:

from qools import funcutils

called_once — run once decorator

The called_once decorator ensures a function executes only once. All subsequent calls return the cached result without re-executing the function body. The decorator is thread-safe.

from qools import funcutils

@funcutils.called_once
def load_config():
    print("Loading config...")
    return {"key": "value"}

# First call — executes the function
config = load_config()  # Loading config...

# Subsequent calls — return cached result
config = load_config()  # (no output, returns {"key": "value"})

Typical use cases:

  • One-time initialization (database connections, config loading)
  • Lazy singletons
  • Expensive computations that should not repeat

Note

If the first call raises an exception, the exception propagates to the caller, but the function is still marked as called — all subsequent calls return None without retrying. Wrap the first call in error handling if a retry may be needed.