cli-speeder

Make your Python CLIs start instantly (10x-100x faster). Python scripts are notoriously slow to start because they import heavy libraries (like pandas, torch, boto3, pydantic) at the top level, even if the user only runs a simple command like --help.

cli-speeder fixes this with zero code refactoring.

Installation

pip install cli-speeder

Usage

There are two ways to use this.

Method 1: The "One-Liner" (Recommended)

Add this once at the very top of your script (before your heavy imports).

from cli_speeder import speed_up_modules
# Magic: Forces these modules to load lazily
speed_up_modules(["pandas", "tensorflow", "boto3"])

# --- Your normal code stays exactly the same! ---
import pandas as pd      \# 0ms (Instant)
import tensorflow as tf  \# 0ms (Instant)
import boto3             \# 0ms (Instant)

def process_data():
\# The libraries only actually load HERE, when you use them.
df = pd.read_csv("data.csv")

Method 2: Manual Proxy (Granular Control)

If you want specific control over exactly which object is lazy.

from cli_speeder import lazy_import, lazy_from_import

# Replace 'import pandas as pd' with:
pd = lazy_import("pandas")

# Replace 'from pandas import DataFrame' with:
DataFrame = lazy_from_import("pandas", "DataFrame")

Benchmarks

Time to run python script.py --help:

Debugging / Production Safety

Lazy loading is great for CLIs, but sometimes (like in production workers) you might want standard behavior to catch ImportError immediately.

You can force all imports to happen immediately (disable lazy loading) by setting an environment variable:

export CLI_SPEEDER_EAGER=1
python my_script.py

License

cli_speeder is licensed under the Apache License 2.0. See the LICENSE file for more details.