pyp2req 0.1.1

pyproject.toml to requirements.txt converter

pyp2req - pyproject.toml to requirements.txt converter

Have you ever wanted to obtain the dependencies from a pyproject.toml file in a requirements.txt format (i.e. in a format you can pass to pip install -r)?

If so, you've found the correct tool.

What this does

It outputs all of the various dependencies defined in PEP 621 and PEP 518 (to be more specific, it supports project.dependencies, project.optional-dependencies, and also build-system.requires) in a requirements.txt-compatible format to the standard output.

What this does not do

• validate a given pyproject.toml file (or that the dependencies can be resolved for that matter)
• parse any requirements from any tool-specific key (like [tool.poetry.dependencies])
• read any of the other keys from the pyproject.toml file
• parse any "dynamic" dependency specifications (as supported by some tools)

Why is this useful?

In case you have a project which already has a build system (say, CMake), and wish to extend it to use pyproject.toml (for instance, if you want to distribute wheels), but do not want the hassle of going through the pyproject.toml file just to extract the dependencies.

Why not use X instead?

• pip: does not support actually parsing the pyproject.toml file, or installing only the dependencies without also installing the main project (keep a close eye on this issue and PEP 735 though!)
• Poetry: can install optional dependencies, but only those defined in the [tool.poetry] key
• pip-tools: close, but it actually does too much, and pins all dependencies (including any transitive dependencies) to specific versions, which is great if you want to be very strict with your versioning, but not so much if want to be a bit more relaxed. It also tries to resolve all of the dependencies first, making it a bit slow

Okay, how do I use this then?

To install from PyPI:

pip install pyp2req

To get all dependencies, pass the directory containing the pyproject.toml file as the argument:

pyp2req /path/to/dir_with_pyproject

For instance, here's the output of pyp2req on this project:

# build time dependencies
setuptools
setuptools-scm>=8.0.0
# run time dependencies
tomli;python_version<'3.11'

Customization

By default, all of the dependencies (build, run, optional) are shown, but this can be customized.

Removing build system dependencies

Run:

pyp2req -b /path/to/dir_with_pyproject

Removing run dependencies

Run:

pyp2req -r /path/to/dir_with_pyproject

Only selecting certain optional dependencies

Run:

pyp2req -t [TYPE] /path/to/dir_with_pyproject

where you can replace [TYPE] with any of the optional dependencies specified (it's also additive, meaning you can specify multiple dependencies).

Note that if you only want the optional dependencies, you need to disable the build and run dependencies by adding -b -r to the above invocation.

Listing optional dependencies

PEP 621 specifies that optional-dependencies should not be a list, but rather a dictionary, meaning you can specify groups of dependencies (for instance, test, docs, etc.), so you may wish to figure what those are first. In order to make life easier, you can run:

pyp2req -l /path/to/dir_with_pyproject

which will list all of the optional groups that are defined in the project. Note that using this option makes the program ignore any other option specified.

Removing comments

You can output a version without comments using:

pyp2reqs -c /path/to/dir_with_pyproject

License

MIT

FAQ

I keep getting the message error: the following arguments are required: dir when I use the -t option

There are 2 solutions here:

1. put the arguments to the -t option after specifying the directory: pyp2req /path/to/dir_with_pyproject -t typ1 typ2
2. use -- to signify end of parsing options and start of mandatory arguments: pyp2req -t typ1 typ2 -- /path/to/dir_with_pyproject

Can I directly install the requirements using pip without saving to a file?

In Bash and Zsh shells (Linux and MacOS defaults) you can take advantage of process substitution:

pip install -r <(pyp2req /path/to/dir_with_pyproject)