# Puffin [![Puffin](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/puffin/main/assets/badge/v0.json)](https://github.com/astral-sh/puffin) [![image](https://img.shields.io/pypi/v/puffin-alpha.svg)](https://pypi.python.org/pypi/puffin-alpha) [![image](https://img.shields.io/pypi/l/puffin-alpha.svg)](https://pypi.python.org/pypi/puffin-alpha) [![image](https://img.shields.io/pypi/pyversions/puffin-alpha.svg)](https://pypi.python.org/pypi/puffin-alpha) [![Actions status](https://github.com/astral-sh/puffin/workflows/CI/badge.svg)](https://github.com/astral-sh/puffin/actions) [![Discord](https://img.shields.io/badge/Discord-%235865F2.svg?logo=discord&logoColor=white)](https://discord.gg/astral-sh) An extremely fast Python package installer and resolver, written in Rust. Designed as a drop-in replacement for `pip` and `pip-compile`. Puffin is backed by [Astral](https://astral.sh), the creators of [Ruff](https://github.com/astral-sh/ruff). ## Highlights - โš–๏ธ Drop-in replacement for common `pip`, `pip-tools`, and `virtualenv` commands. - โšก๏ธ 10-100x faster than `pip` and `pip-tools` (`pip-compile` and `pip-sync`). - ๐Ÿ’พ Disk-space efficient, with a global cache for dependency deduplication. - ๐Ÿ Installable via `pip`, `pipx`, `brew` etc. Puffin is a static binary that can be installed without Rust or Python. - ๐Ÿงช Tested at-scale against the top 10,000 PyPI packages. - ๐Ÿ–ฅ๏ธ Support for macOS, Linux, and Windows. - ๐Ÿงฐ Novel features such as [dependency version overrides](#dependency-overrides] and [alternative resolution strategies](#resolution-strategy). - โ‰๏ธ Best-in-class error messages with a conflict-tracking resolver. - ๐Ÿค Support for a wide range of advanced `pip` features, including: editable installs, Git dependencies, direct URL dependencies, local dependencies, constraints, source distributions, HTML and JSON indexes, and more. ## Getting Started Puffin is available as [`puffin`](https://pypi.org/project/puffin/) on PyPI: ```shell pipx install puffin ``` To create a virtual environment with Puffin: ```shell puffin venv # Create a virtual environment at .venv. ``` To install a package into the virtual environment: ```shell puffin pip install flask # Install Flask. puffin pip install -r requirements.txt # Install from a requirements.txt file. puffin pip install -e . # Install the current project in editable mode. ``` To generate a set of locked dependencies from an input file: ```shell puffin pip compile pyproject.toml -o requirements.txt # Read a pyproject.toml file. puffin pip compile requirements.in -o requirements.txt # Read a requirements.in file. ``` To install a set of locked dependencies into the virtual environment: ```shell puffin pip sync requirements.txt # Install from a requirements.txt file. ``` Puffin's `pip-install` and `pip-compile` commands supports many of the same command-line arguments as existing tools, including `-r requirements.txt`, `-c constraints.txt`, `-e .` (for editable installs), `--index-url`, and more. ## Roadmap Puffin is an extremely fast Python package resolver and installer, designed as a drop-in replacement for `pip` and `pip-tools` (`pip-compile` and `pip-sync`). Puffin is not a complete package manager. Instead, it represents an intermediary goal in our pursuit of a "Cargo for Python": a Python package and project manager that is extremely fast, reliable, and easy to use โ€” a single tool capable of unifying not only `pip` and `pip-tools`, but also `pipx`, `virtualenv`, `tox`, `setuptools`, `poetry`, `pyenv`, `rye`, and more. In the future, Puffin will be used as the foundation for such a tool: a single binary that bootstraps your Python installation and gives you everything you need to be productive with Python. In the meantime, though, Puffin's narrower scope allows us to solve many of the low-level problems that are required to build such a package manager (like package installation) while shipping an immediately useful tool with a minimal barrier to adoption. Try it today in lieu of `pip` and `pip-compile`. ## Limitations Puffin does not support the entire `pip` feature set. Namely, Puffin does not plan to support the following `pip` features: - `.egg` dependencies - Editable installs for Git and direct URL dependencies (editable installs _are_ supported for local dependencies) On the other hand, Puffin plans to (but does not currently) support: - [Hash-checking mode](https://github.com/astral-sh/puffin/issues/474) - [URL requirements without package names](https://github.com/astral-sh/puffin/issues/313) (e.g., `https://...` instead of `package @ https://...`). Like `pip-compile`, Puffin generates a platform-specific `requirements.txt` file (unlike, e.g., `poetry` and `pdm`, which generate platform-agnostic `poetry.lock` and `pdm.lock` files). As such, Puffin's `requirements.txt` files may not be portable across platforms and Python versions. ## Advanced Usage ### Python discovery Puffin itself does not depend on Python, but it does need to locate a Python environment to (1) install dependencies into the environment and (2) build source distributions. When running `pip sync` or `pip install`, Puffin will search for a virtual environment in the following order: - An activated virtual environment based on the `VIRTUAL_ENV` environment variable. - An activated Conda environment based on the `CONDA_PREFIX` environment variable. - A virtual environment at `.venv` in the current directory, or in the nearest parent directory. If no virtual environment is found, Puffin will prompt the user to create one in the current directory via `puffin venv`. When running `pip compile`, Puffin does not _require_ a virtual environment and will search for a Python interpreter in the following order: - An activated virtual environment based on the `VIRTUAL_ENV` environment variable. - An activated Conda environment based on the `CONDA_PREFIX` environment variable. - A virtual environment at `.venv` in the current directory, or in the nearest parent directory. - The Python interpreter available as `python3` on macOS and Linux, or `python.exe` on Windows. If a `--python-version` is provided to `pip compile` (e.g., `--python-version=3.7`), Puffin will search for a Python interpreter matching that version in the following order: - An activated virtual environment based on the `VIRTUAL_ENV` environment variable. - An activated Conda environment based on the `CONDA_PREFIX` environment variable. - A virtual environment at `.venv` in the current directory, or in the nearest parent directory. - The Python interpreter available as, e.g., `python3.7` on macOS and Linux. On Windows, Puffin will use the same mechanism as `py --list-paths` to discover all available Python interpreters, and will select the first interpreter matching the requested version. - The Python interpreter available as `python3` on macOS and Linux, or `python.exe` on Windows. Since Puffin has no dependency on Python, it can even install into virtual environments other than its own. For example, setting `VIRTUAL_ENV=/path/to/venv` will cause Puffin to install into `/path/to/venv`, no matter where Puffin is installed. ### Dependency caching Puffin uses aggressive caching to avoid re-downloading (and re-building dependencies) that have already been accessed in prior runs. The specifics of Puffin's caching semantics vary based on the nature of the dependency: - **For registry dependencies** (like those downloaded from PyPI), Puffin respects HTTP caching headers. - **For direct URL dependencies**, Puffin respects HTTP caching headers, and also caches based on the URL itself. - **For Git dependencies**, Puffin caches based on the fully-resolved Git commit hash. As such, `puffin pip compile` will pin Git dependencies to a specific commit hash when writing the resolved dependency set. - **For local dependencies**, Puffin caches based on the last-modified time of the `setup.py` or `pyproject.toml` file. If you're running into caching issues, Puffin includes a few escape hatches: - To force Puffin to ignore cached data for all dependencies, run `puffin pip install --reinstall ...`. - To force Puffin to ignore cached data for a specific dependency, run, e.g., `puffin pip install --reinstall-package flask ...`. - To clear the global cache entirely, run `puffin clean`. ### Resolution strategy By default, Puffin follows the standard Python dependency resolution strategy of preferring the latest compatible version of each package. For example, `puffin pip install flask>=2.0.0` will install the latest version of Flask (at time of writing: `3.0.0`). However, Puffin's resolution strategy be configured to prefer the _lowest_ compatible version of each package (`--resolution=lowest`), or even the lowest compatible version of any _direct_ dependencies (`--resolution=lowest-direct`), both of which can be useful for library authors looking to test their packages against the oldest supported versions of their dependencies. For example, given the following `requirements.in` file: ```text flask>=2.0.0 ``` Running `puffin pip compile requirements.in` would produce the following `requirements.txt` file: ```text # This file was autogenerated by Puffin v0.0.1 via the following command: # puffin pip compile requirements.in blinker==1.7.0 # via flask click==8.1.7 # via flask flask==3.0.0 itsdangerous==2.1.2 # via flask jinja2==3.1.2 # via flask markupsafe==2.1.3 # via # jinja2 # werkzeug werkzeug==3.0.1 # via flask ``` However, `puffin pip compile --resolution=lowest requirements.in` would instead produce: ```text # This file was autogenerated by Puffin v0.0.1 via the following command: # puffin pip compile requirements.in --resolution=lowest click==7.1.2 # via flask flask==2.0.0 itsdangerous==2.0.0 # via flask jinja2==3.0.0 # via flask markupsafe==2.0.0 # via jinja2 werkzeug==2.0.0 # via flask ``` ### Pre-release handling By default, Puffin will accept pre-release versions during dependency resolution in two cases: 1. If the package is a direct dependency, and its version markers include a pre-release specifier (e.g., `flask>=2.0.0rc1`). 1. If _all_ published versions of a package are pre-releases. If dependency resolution fails due to a transitive pre-release, Puffin will prompt the user to re-run with `--prerelease=allow`, to allow pre-releases for all dependencies. Alternatively, you can add the transitive dependency to your `requirements.in` file with pre-release specifier (e.g., `flask>=2.0.0rc1`) to opt in to pre-release support for that specific dependency. Pre-releases are [notoriously difficult](https://pubgrub-rs-guide.netlify.app/limitations/prerelease_versions) to model, and are a frequent source of bugs in other packaging tools. Puffin's pre-release handling is _intentionally_ limited and _intentionally_ requires user intervention to opt in to pre-releases to ensure correctness, though pre-release handling will be revisited in future releases. ### Dependency overrides Historically, `pip` has supported "constraints" (`-c constraints.txt`), which allows users to narrow the set of acceptable versions for a given package. Puffin supports constraints, but also takes this concept further by allowing users to _override_ the acceptable versions of a package across the dependency tree via overrides (`-o overrides.txt`). In short, overrides allow the user to lie to the resolver by overriding the declared dependencies of a package. Overrides are a useful last resort for cases in which the user knows that a dependency is compatible with a newer version of a package than the package declares, but the package has not yet been updated to declare that compatibility. For example, if a transitive dependency declares `pydantic>=1.0,<2.0`, but the user knows that the package is compatible with `pydantic>=2.0`, the user can override the declared dependency with `pydantic>=2.0,<3` to allow the resolver to continue. While constraints are purely _additive_, and thus cannot _expand_ the set of acceptable versions for a package, overrides _can_ expand the set of acceptable versions for a package, providing an escape hatch for erroneous upper version bounds. ### Multi-version resolution Puffin's `pip-compile` command produces a resolution that's known to be compatible with the current platform and Python version. Unlike Poetry, PDM, and other package managers, Puffin does not yet produce a machine-agnostic lockfile. However, Puffin _does_ support resolving for alternate Python versions via the `--python-version` command line argument. For example, if you're running Puffin on Python 3.9, but want to resolve for Python 3.8, you can run `puffin pip compile --python-version=3.8 requirements.in` to produce a Python 3.8-compatible resolution. ## Platform support Puffin has Tier 1 support for the following platforms: - macOS (Apple Silicon) - macOS (x86_64) - Linux (x86_64) - Windows (x86_64) Puffin is continuously built, tested, and developed against its Tier 1 platforms. Inspired by the Rust project, Tier 1 can be thought of as ["guaranteed to work"](https://doc.rust-lang.org/beta/rustc/platform-support.html). Puffin has Tier 2 support ("guaranteed to build") for the following platforms: - Linux (PPC64) - Linux (PPC64LE) - Linux (aarch64) - Linux (armv7) - Linux (i686) - Linux (s390x) Puffin ships pre-built wheels to [PyPI](https://pypi.org/project/puffin-alpha/) for its Tier 1 and Tier 2 platforms. However, while Tier 2 platforms are continuously built, they are not continuously tested or developed against, and so stability may vary in practice. Beyond the Tier 1 and Tier 2 platforms, Puffin is known to build on i686 Windows, and known _not_ to build on aarch64 Windows, but does not consider either platform to be supported at this time. Puffin supports and is tested against Python 3.8, 3.9, 3.10, 3.11, and 3.12. ## Acknowledgements Puffin's dependency resolver uses [PubGrub](https://github.com/pubgrub-rs/pubgrub) under the hood. We're grateful to the PubGrub maintainers, especially [Jacob Finkelman](https://github.com/Eh2406), for their support. Puffin's Git implementation draws on details from [Cargo](https://github.com/rust-lang/cargo). Some of Puffin's optimizations are inspired by the great work we've seen in [Orogene](https://github.com/orogene/orogene) and [Bun](https://github.com/oven-sh/bun). We've also learned a lot from Nathaniel J. Smith's [Posy](https://github.com/njsmith/posy) and adapted its [trampoline](https://github.com/njsmith/posy/tree/main/src/trampolines/windows-trampolines/posy-trampoline). ## License Puffin is licensed under either of - Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or https://www.apache.org/licenses/LICENSE-2.0) - MIT license ([LICENSE-MIT](LICENSE-MIT) or https://opensource.org/licenses/MIT) at your option. Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in Puffin by you, as defined in the Apache-2.0 license, shall be dually licensed as above, without any additional terms or conditions.