λ-trim

λ-trim is a debloater for Python applications. Given a Python function and a set of inputs to this function λ-trim automatically removes all redundant modules, functions and classes from the modules that the application imports.

Installation

Install λ-trim from PyPI:

pip install ltrim

Usage

Basic Usage

To run the debloater against a Python script file.py, a testcase file with a specific structure is needed (see Test cases format from our accompanying benchmark repository).

debloat /path/to/code/file.py

By default, λ-trim assumes the existence of the testcases fike under the name data.json in the current working directory. You can also specify the path to this file with the -t, --testcases flag, like:

debloat /path/to/code/file.py -t /path/to/code/data.json

Scoring Methods

Users can specify the number of modules that they want to debloat by using the -k flag. Additionally, the ranking of the top K modules can be set by using the -s, --scoring flag. λ-trim currently supports the following scoring methods:

• cost, which corresponds to the serverless cost models and takes into account both import time and memory footprint (default)
• time, which ranks modules based on import time
• memory, which ranks modules based on memory footprint
• random, which ranks modules randomly.

Users can provide their own custom scoring functions by extending the scoring function in ltrim/debloat/utils.

Citation

Please use the following citation when reffering to the source code and/or the accompanying paper

@article{pavlatos2025lambdatrim,
  title={𝜆-trim: Reducing Monetary and Performance Cost of Serverless Cold Starts with Cost-driven Application Debloating},
  author={Liu, Xuting and Pavlatos, Spyros and Liu, Yuhao and Liu, Vincent},
  journal={UNDER SUBMISSION},
  year={2025}
}

License

This project is licensed under the GNU General Public License v3.0.

You are free to use, modify, and distribute this software under the terms of the GPL-3.0 License.

Copyright (C) 2025 University of Pennsylvania

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <https://www.gnu.org/licenses/>.