creosote

Identify unused dependencies and avoid a bloated virtual environment.

⚡️ Quickstart

Install creosote in separate virtual environment (using e.g. pipx):

pipx install creosote

Scan virtual environment for unused dependencies (PEP-621 example below, but Poetry, Pipenv, PDM and requirements.txt files are also supported, see this table):

$ creosote
Found dependencies in pyproject.toml: dotty-dict, loguru, pip-requirements-parser, requests, toml
Oh no, bloated venv! 🤢 🪣
Unused dependencies found: requests

And after having removed/uninstalled requests:

$ creosote
Found dependencies in pyproject.toml: dotty-dict, loguru, pip-requirements-parser, toml
No unused dependencies found! ✨

Get help:

creosote --help

🤔 How this works

☘️ Required arguments

The creosote tool will first scan the given python file(s) for all its imports. Then it fetches all dependency names (from the dependencies spec file). Finally, all imports are associated with their corresponding dependency name (requires the virtual environment for resolving). If a dependency does not have any imports associated, it is considered unused.

See the main function in cli.py for a terse overview of the logic.

🌶️ Features

These optional features enable new/experimental functionality, that may be backward incompatible and may be removed/changed at any time. Some features may become mandatory for a target release version e.g. the next major release. Enable using --use-feature <FEATURE>. Use at your own risk!

😤 Known limitations

• importlib imports are not detected by the AST parser (a great first contribution for anyone inclined 😄, reach out or start here).

🥧 History and ambition

This project was inspired by security vulnerability reports about production dependencies that were shipped into production but turned out to be unused. Creosote aims to help prevent such occurrences and reduce noise from bots like Dependabot or Renovate for simply unused dependencies.

The intent is to run Creosote in CI (or with pre-commit) to detect cases where developers forget to remove unused dependencies, especially during refactorings. Creosote can identify both unused production dependencies and developer dependencies, depending on your objectives.

🤨 FAQ

Which dependency specification tooling/standards are supported?

📔 Notes on PEP-508 (requirements.txt)

When using requirements.txt files to specify dependencies, there is no way to tell which part of requirements.txt specifies production vs developer dependencies. Therefore, you have to break your requirements.txt file into e.g. requirements-prod.txt and requirements-dev.txt and use any of them as input. When using pip-tools, you likely want to point Creosote to scan your *.in file(s).

📓 Notes on PEP-582 (__pypackages__)

Creosote supports the __pypackages__ folder, although PEP-582 was rejected. There is no reason to remove support for this today, but in case supporting this becomes cumbersome in the future, supporting PEP-582 might be dropped.

creosote --venv __pypackages__

Can I specify multiple toml sections?

Yes, you can specify a list of sections after the --sections argument. It all depends on what your setup looks like and what you set out to achieve.

$ creosote --sections project.dependencies project.optional-dependencies.lint project.optional-dependencies.test

Can I exclude dependencies from the scan?

Yes, you can use the --exclude-deps argument to specify one or more dependencies you do not wish to get warnings for.

This feature is intended for dependencies you must specify in your dependencies spec file, but which you don't import in your source code. An example of such a dependency are database drivers, which are commonly only defined in connection strings and will signal to the ORM which driver to use.

$ creosote --exclude-deps pyodbc pg8000

Can I run Creosote in a GitHub Action workflow?

Yes, please see the action job example in .github/workflows/test.yml.

Can I run Creosote with pre-commit?

Yes, see example in .pre-commit-config.yaml.

# .pre-commit-config.yaml

repos:
  - repo: local
    hooks:
      - id: system
        name: creosote
        entry: creosote --venv .venv --paths src --deps-file pyproject.toml --sections project.dependencies
        pass_filenames: false
        files: \.(py|toml|txt|in|lock)$
        language: system

What's with the name "creosote"?

This tool has borrowed its name from the Monty Python scene about Mr. Creosote.

📰 Creosote in the "news"

Because it makes me happy to see this tool can help others! 🥰

• Creosote - Identify unused dependencies and avoid a bloated virtual environment — Reddit

👩‍🔬 Development/debugging info

Install in-development builds

You can run in-development versions of Creosote. Examples below:

# Creosote build from main branch
$ pipx install --suffix=@main --force git+https://github.com/fredrikaverpil/creosote.git@main
$ creosote@main --venv .venv ...
$ pipx uninstall creosote@main

# Creosote build from PR #123
$ pipx install --suffix=@123 --force git+https://github.com/fredrikaverpil/creosote.git@refs/pull/123/head
$ creosote@123 --venv .venv ...
$ pipx uninstall creosote@123

🚀 Releasing

1. Bump version in src/creosote/__about__.py and .pre-commit-config.yaml.
2. GitHub Action will run automatically on creating a release and deploy the release onto PyPi.