## Summary and motivation
For a given source dist, we store the metadata of each wheel built
through it in `built-wheel-metadata-v0/pypi/<source dist
filename>/metadata.json`. During resolution, we check the cache status
of the source dist. If it is fresh, we check `metadata.json` for a
matching wheel. If there is one we use that metadata, if there isn't, we
build one. If the source is stale, we build a wheel and override
`metadata.json` with that single wheel. This PR thereby ties the local
built wheel metadata cache to the freshness of the remote source dist.
This functionality is available through `SourceDistCachedBuilder`.
`puffin_installer::Builder`, `puffin_installer::Downloader` and
`Fetcher` are removed, instead there are now `FetchAndBuild` which calls
into the also new `SourceDistCachedBuilder`. `FetchAndBuild` is the new
main high-level abstraction: It spawns parallel fetching/building, for
wheel metadata it calls into the registry client, for wheel files it
fetches them, for source dists it calls `SourceDistCachedBuilder`. It
handles locks around builds, and newly added also inter-process file
locking for git operations.
Fetching and building source distributions now happens in parallel in
`pip-sync`, i.e. we don't have to wait for the largest wheel to be
downloaded to start building source distributions.
In a follow-up PR, I'll also clear built wheels when they've become
stale.
Another effect is that in a fully cached resolution, we need neither zip
reading nor email parsing.
Closes #473
## Source dist cache structure
Entries by supported sources:
* `<build wheel metadata cache>/pypi/foo-1.0.0.zip/metadata.json`
* `<build wheel metadata
cache>/<sha256(index-url)>/foo-1.0.0.zip/metadata.json`
* `<build wheel metadata
cache>/url/<sha256(url)>/foo-1.0.0.zip/metadata.json`
But the url filename does not need to be a valid source dist filename
(<https://github.com/search?q=path%3A**%2Frequirements.txt+master.zip&type=code>),
so it could also be the following and we have to take any string as
filename:
* `<build wheel metadata
cache>/url/<sha256(url)>/master.zip/metadata.json`
Example:
```text
# git source dist
pydantic-extra-types @ git+https://github.com/pydantic/pydantic-extra-types.git
# pypi source dist
django_allauth==0.51.0
# url source dist
werkzeug @ ff1904eb5e/werkzeug-3.0.1.tar.gz
```
will be stored as
```text
built-wheel-metadata-v0
├── git
│ └── 5c56bc1c58c34c11
│ └── 843b753e9e8cb74e83cac55598719b39a4d5ef1f
│ └── metadata.json
├── pypi
│ └── django-allauth-0.51.0.tar.gz
│ └── metadata.json
└── url
└── 6781bd6440ae72c2
└── werkzeug-3.0.1.tar.gz
└── metadata.json
```
The inside of a `metadata.json`:
```json
{
"data": {
"django_allauth-0.51.0-py3-none-any.whl": {
"metadata-version": "2.1",
"name": "django-allauth",
"version": "0.51.0",
...
}
}
}
```
Crates
bench
Functionality for benchmarking Puffin.
distribution-filename
Parse built distribution (wheel) and source distribution (sdist) filenames to extract structured metadata.
distribution-types
Abstractions for representing built distributions (wheels) and source distributions (sdists), and the sources from which they can be downloaded.
gourgeist
A venv replacement to create virtual environments in Rust.
install-wheel-rs
Install built distributions (wheels) into a virtual environment.]
pep440-rs
Utilities for interacting with Python version numbers and specifiers.
pep508-rs
Utilities for interacting with PEP 508 dependency specifiers.
platform-host
Functionality for detecting the current platform (operating system, architecture, etc.).
platform-tags
Functionality for parsing and inferring Python platform tags as per PEP 425.
puffin-build
A PEP 517-compatible build frontend for Puffin.
puffin-cache
Functionality for caching Python packages and associated metadata.
puffin-cli
Command-line interface for the Puffin package manager.
puffin-client
Client for interacting with PyPI-compatible HTTP APIs.
puffin-dev
Development utilities for Puffin.
puffin-dispatch
A centralized struct for resolving and building source distributions in isolated environments.
Implements the traits defined in puffin-traits.
puffin-distribution
Client for interacting with built distributions (wheels) and source distributions (sdists). Capable of fetching metadata, distribution contents, etc.
puffin-git
Functionality for interacting with Git repositories.
puffin-installer
Functionality for installing Python packages into a virtual environment.
puffin-interpreter
Functionality for detecting and leveraging the current Python interpreter.
puffin-macros
Reusable procedural macros for Puffin.
puffin-normalize
Normalize package and extra names as per Python specifications.
puffin-package
Types and functionality for working with Python packages, e.g., parsing wheel files.
puffin-resolver
Functionality for resolving Python packages and their dependencies.
puffin-traits
Shared traits for Puffin, to avoid circular dependencies.
pypi-types
General-purpose type definitions for types used in PyPI-compatible APIs.
requirements-txt
Functionality for parsing requirements.txt files.