## Background
In virtual environments, we want to install python programs as console
commands, e.g. `black .` over `python -m black .`. They may be called
[entrypoints](https://packaging.python.org/en/latest/specifications/entry-points/)
or scripts. For entrypoints, we're given a module name and function to
call in that module.
On Unix, we generate a minimal python script launcher. Text files are
runnable on unix by adding a shebang at their top, e.g.
```python
#!/usr/bin/env python
```
will make the operating system run the file with the current python
interpreter. A venv launcher for black in `/home/ferris/colorize/.venv`
(module name: `black`, function to call: `patched_main`) would look like
this:
```python
#!/home/ferris/colorize/.venv/bin/python
# -*- coding: utf-8 -*-
import re
import sys
from black import patched_main
if __name__ == "__main__":
sys.argv[0] = re.sub(r"(-script\.pyw|\.exe)?$", "", sys.argv[0])
sys.exit(patched_main())
```
On windows, this doesn't work, we can only rely on launching `.exe`
files.
## Summary
We use posy's rust implementation of a trampoline, which is based on
distlib's c++ implementation. We pre-build a minimal exe and append the
launcher script as stored zip archive behind it. The exe will look for
the venv python interpreter next to it and use it to execute the
appended script.
The changes in this PR make the `black` entrypoint work:
```powershell
cargo run -- venv .venv
cargo run -q -- pip install black
.\.venv\Scripts\black --version
```
Integration with our existing tests will be done in follow-up PRs.
## Implementation and Details
I've vendored the posy trampoline crate. It is a formatted, renamed and
slightly changed for embedding version of
https://github.com/njsmith/posy/pull/28.
The posy launchers are smaller than the distlib launchers, 16K vs 106K
for black. Currently only `x86_64-pc-windows-msvc` is supported. The
crate requires a nightly compiler for its no-std binary size tricks.
On windows, an application can be launched with a console or without (to
create windows instead), which needs two different launchers. The gui
launcher will subsequently use `pythonw.exe` while the console launcher
uses `python.exe`.
## Summary
This makes the separation clearer between the legacy `pip` API and the
API we'll add in the future for the package manager itself. It also
enables seamless `puffin pip` aliasing for those that want it.
Closes#918.
The semantics are a bit unintuitive because `--python-version` is a
preference when looking for a python version without a venv, but if we
don't find that exact version we'll take `python3` and patch the
markers. This will make more sense once we start provisioning python
builds.
We can now resolve black with both python 3.8 and 3.12, with or without
that python version being in scope. In the example below,
`PATH=$HOME/.cargo/bin:/usr/bin` removes the pyenv builds and leaves
only `python3`, which is python 3.11.
```console
$ RUST_LOG=puffin::commands=debug cargo run --bin puffin -q -- pip-compile -v scripts/benchmarks/requirements/black.in --python-version py38
0.004108s DEBUG puffin::commands::pip_compile Using Python 3.8 at /home/konsti/.local/bin/python3.8
Resolved 8 packages in 44ms
# This file was autogenerated by Puffin v0.0.1 via the following command:
# puffin pip-compile -v scripts/benchmarks/requirements/black.in --python-version py38
black==23.11.0
[...]
platformdirs==4.0.0
# via black
tomli==2.0.1
# via black
typing-extensions==4.8.0
# via black
$ PATH=$HOME/.cargo/bin:/usr/bin RUST_LOG=puffin::commands=debug cargo run --bin puffin -q -- pip-compile -v scripts/benchmarks/requirements/black.in --python-version py38
0.004315s DEBUG puffin::commands::pip_compile Using Python 3.11 at /usr/bin/python3
Resolved 8 packages in 43ms
# This file was autogenerated by Puffin v0.0.1 via the following command:
# puffin pip-compile -v scripts/benchmarks/requirements/black.in --python-version py38
black==23.11.0
[...]
platformdirs==4.0.0
# via black
tomli==2.0.1
# via black
typing-extensions==4.8.0
# via black
```
```console
$ RUST_LOG=puffin::commands=debug cargo run --bin puffin -q -- pip-compile -v scripts/benchmarks/requirements/black.in --python-version py312
0.004216s DEBUG puffin::commands::pip_compile Using Python 3.12 at /home/konsti/.local/bin/python3.12
Resolved 6 packages in 37ms
# This file was autogenerated by Puffin v0.0.1 via the following command:
# puffin pip-compile -v scripts/benchmarks/requirements/black.in --python-version py312
black==23.11.0
[...]
platformdirs==4.0.0
# via black
$ PATH=$HOME/.cargo/bin:/usr/bin RUST_LOG=puffin::commands=debug cargo run --bin puffin -q -- pip-compile -v scripts/benchmarks/requirements/black.in --python-version py312
0.004190s DEBUG puffin::commands::pip_compile Using Python 3.11 at /usr/bin/python3
Resolved 6 packages in 39ms
# This file was autogenerated by Puffin v0.0.1 via the following command:
# puffin pip-compile -v scripts/benchmarks/requirements/black.in --python-version py312
black==23.11.0
[...]
platformdirs==4.0.0
# via black
```
Fixes#235.
Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>
## Summary
This PR adds support for local path dependencies. The approach mostly
just falls out of our existing approach and infrastructure for Git and
URL dependencies.
Closes https://github.com/astral-sh/puffin/issues/436. (We'll open a
separate issue for editable installs.)
## Test Plan
Added `pip-compile` tests that pre-download a wheel or source
distribution, then install it via local path.
This PR massively speeds up the case in which you need to install wheels
that already exist in the global cache.
The new strategy is as follows:
- Download the wheel into the content-addressed cache.
- Unzip the wheel into the cache, but ignore content-addressing. It
turns out that writing to `cacache` for every file in the zip added a
ton of overhead, and I don't see any actual advantages to doing so.
Instead, we just unzip the contents into a directory at, e.g.,
`~/.cache/puffin/django-4.1.5`.
- (The unzip itself is now parallelized with Rayon.)
- When installing the wheel, we now support unzipping from a directory
instead of a zip archive. This required duplicating and tweaking a few
functions.
- When installing the wheel, we now use reflinks (or copy-on-write
links). These have a few fantastic properties: (1) they're extremely
cheap to create (on macOS, they are allegedly faster than hard links);
(2) they minimize disk space, since we avoid copying files entirely in
the vast majority of cases; and (3) if the user then edits a file
locally, the cache doesn't get polluted. Orogene, Bun, and soon pnpm all
use reflinks.
Puffin is now ~15x faster than `pip` for the common case of installing
cached data into a fresh environment.
Closes https://github.com/astral-sh/puffin/issues/21.
Closes https://github.com/astral-sh/puffin/issues/39.
konsti
Zanie Blue
Charlie Marsh