The pyproject.toml config file — Flit 3.12.0 documentation

# The pyproject.toml config file

This file lives next to the module or package.

Note

Older version of Flit (up to 0.11) used a flit.ini file for similar information. These files no longer work with Flit 3 and above.

Run `python3 -m flit.tomlify` to convert a `flit.ini` file to `pyproject.toml`.

## Build system section

This tells tools like pip to build your project with flit. It’s a standard defined by PEP 517. For any new project using Flit, it will look like this:

    [build-system]
    requires = ["flit_core >=3.11,<4"]
    build-backend = "flit_core.buildapi"

Version constraints:

- For now, all packages should specify `<4`, so they won’t be impacted by changes in the next major version.

- `license-files` and license expressions in the `license` field require `flit_core >=3.11`.

- New style metadata requires `flit_core >=3.2`

- Old style metadata requires `flit_core >=2,<4`

- The older flit.ini file requires `flit_core <3`.

- TOML features new in version 1.0 require `flit_core >=3.4`.

- `flit_core` 3.3 is the last version supporting Python 3.4 & 3.5. Packages supporting these Python versions can only use TOML v0.5.

- Only `flit_core` 2.x can build packages on Python 2, so packages still supporting Python 2 cannot use new-style metadata (the `[project]` table).

## New style metadata

Added in version 3.2.

The new standard way to specify project metadata is in a `[project]` table, as defined by PEP 621. Flit works for now with either this or the older `[tool.flit.metadata]` table (described below), but it won’t allow you to mix them.

A simple `[project]` table might look like this:

    [project]
    name = "astcheck"
    authors = [
        {name = "Thomas Kluyver", email = "thomas@kluyver.me.uk"},
    ]
    readme = "README.rst"
    license = "MIT"
    requires-python = ">=3.5"
    dynamic = ["version", "description"]

The allowed fields are:

name

  The name your package will have on PyPI. This field is required. For Flit, this name, with any hyphens replaced by underscores, is also the default value of the import name (see Module section if that needs to be different).

  Changed in version 3.8: Hyphens in the project name are now translated to underscores for the import name.

version

  Version number as a string. If you want Flit to get this from a `__version__` attribute, leave it out of the TOML config and include “version” in the `dynamic` field.

description

  A one-line description of your project. If you want Flit to get this from the module docstring, leave it out of the TOML config and include “description” in the `dynamic` field.

readme

  A path (relative to the .toml file) to a file containing a longer description of your package to show on PyPI. This should be written in reStructuredText, Markdown or plain text, and the filename should have the appropriate extension (`.rst`, `.md` or `.txt`). Alternatively, `readme` can be a table with either a `file` key (a relative path) or a `text` key (literal text), and an optional `content-type` key (e.g. `text/x-rst`).

requires-python

  A version specifier for the versions of Python this requires, e.g. `~=3.3` or `>=3.3,<4`, which are equivalents.

license

  A valid SPDX license expression or a table with either a `file` key (a relative path to a license file) or a `text` key (the license text).

license-files

  A list of glob patterns for license files to include. Defaults to `['COPYING*', 'LICEN[CS]E*']`.

authors

  A list of tables with `name` and `email` keys (both optional) describing the authors of the project.

maintainers

  Same format as authors.

keywords

  A list of words to help with searching for your package.

classifiers

  A list of Trove classifiers. Add `Private :: Do Not Upload` into the list to prevent a private package from being uploaded to PyPI by accident.

dependencies & optional-dependencies

  See Dependencies.

urls

  See URLs table.

scripts & gui-scripts

  See Scripts section.

entry-points

  See Entry points sections.

dynamic

  A list of field names which aren’t specified here, for which Flit should find a value at build time. Only “version” and “description” are accepted.

### Dependencies

The `dependencies` field is a list of other packages from PyPI that this package needs. Each package may be followed by a version specifier like `>=4.1`, and/or an environment marker after a semicolon. For example:

>     dependencies = [
>         "requests >=2.6",
>         "configparser; python_version == '2.7'",
>     ]

The `[project.optional-dependencies]` table contains lists of packages needed for every optional feature. The requirements are specified in the same format as for `dependencies`. For example:

>     [project.optional-dependencies]
>     test = [
>         "pytest >=2.7.3",
>         "pytest-cov",
>     ]
>     doc = ["sphinx"]

You can call these optional features anything you want, although `test` and `doc` are common ones. You specify them for installation in square brackets after the package name or directory, e.g. `pip install '.[test]'`.

### URLs table

Your project’s page on pypi.org can show a number of links. You can point people to documentation or a bug tracker, for example.

This section is called `[project.urls]` in the file. You can use any names inside it. Here it is for flit:

    [project.urls]
    Documentation = "https://flit.pypa.io"
    Source = "https://github.com/pypa/flit"

### Scripts section

This section is called `[project.scripts]` in the file. Each key and value describes a shell command to be installed along with your package. These work like setuptools ‘entry points’. Here’s the section for flit:

    [project.scripts]
    flit = "flit:main"

This will create a `flit` command, which will call the function `main()` imported from `flit`.

A similar table called `[project.gui-scripts]` defines commands which launch a GUI. This only makes a difference on Windows, where GUI scripts are run without a console.

### Entry points sections

You can declare entry points using sections named `[project.entry-points.groupname]`. E.g. to provide a pygments lexer from your package:

    [project.entry-points."pygments.lexers"]
    dogelang = "dogelang.lexer:DogeLexer"

In each `package:name` value, the part before the colon should be an importable module name, and the latter part should be the name of an object accessible within that module. The details of what object to expose depend on the application you’re extending.

If the group name contains a dot, it must be quoted (`"pygments.lexers"` above). Script entry points are defined in scripts tables, so you can’t use the group names `console_scripts` or `gui_scripts` here.

### Module section

If your package will have different names for installation and import, you should specify the install (PyPI) name in the `[project]` table (see above), and the import name in a `[tool.flit.module]` table:

    [project]
    name = "pynsist"
    # ...

    [tool.flit.module]
    name = "nsist"

Flit looks for the source of the package by its import name. The source may be located either in the directory that holds the `pyproject.toml` file, or in a `src/` subdirectory.

## Old style metadata

Flit’s older way to specify metadata is in a `[tool.flit.metadata]` table, along with `[tool.flit.scripts]` and `[tool.flit.entrypoints]`, described below. This is still recognised for now, but you can’t mix it with New style metadata.

There are three required fields:

module

  The name of the module/package, as you’d use in an import statement.

author

  Your name

author-email

  Your email address

e.g. for flit itself

    [tool.flit.metadata]
    module = "flit"
    author = "Thomas Kluyver"
    author-email = "thomas@kluyver.me.uk"

Changed in version 1.1: `home-page` was previously required.

The remaining fields are optional:

home-page

  A URL for the project, such as its Github repository.

requires

  A list of other packages from PyPI that this package needs. Each package may be followed by a version specifier like `(>=4.1)` or `>=4.1`, and/or an environment marker after a semicolon. For example:

      requires = [
          "requests >=2.6",
          "configparser; python_version == '2.7'",
      ]

requires-extra

  Lists of packages needed for every optional feature. The requirements are specified in the same format as for `requires`. The requirements of the two reserved extras `test` and `doc` as well as the extra `dev` are installed by `flit install`. For example:

      [tool.flit.metadata.requires-extra]
      test = [
          "pytest >=2.7.3",
          "pytest-cov",
      ]
      doc = ["sphinx"]

  Added in version 1.1.

description-file

  A path (relative to the .toml file) to a file containing a longer description of your package to show on PyPI. This should be written in reStructuredText, Markdown or plain text, and the filename should have the appropriate extension (`.rst`, `.md` or `.txt`).

classifiers

  A list of Trove classifiers. Add `Private :: Do Not Upload` into the list to prevent a private package from uploading on PyPI by accident.

requires-python

  A version specifier for the versions of Python this requires, e.g. `~=3.3` or `>=3.3,<4` which are equivalents.

dist-name

  If you want your package’s name on PyPI to be different from the importable module name, set this to the PyPI name.

keywords

  Comma separated list of words to help with searching for your package.

license

  The name of a license, if you’re using one for which there isn’t a Trove classifier. It’s recommended to use Trove classifiers instead of this in most cases.

maintainer, maintainer-email

  Like author, for if you’ve taken over a project from someone else.

Here was the metadata section from flit using the older style:

    [tool.flit.metadata]
    module="flit"
    author="Thomas Kluyver"
    author-email="thomas@kluyver.me.uk"
    home-page="https://github.com/pypa/flit"
    requires=[
        "flit_core >=2.2.0",
        "requests",
        "docutils",
        "tomli",
        "tomli-w",
    ]
    requires-python=">=3.6"
    description-file="README.rst"
    classifiers=[
        "Intended Audience :: Developers",
        "License :: OSI Approved :: BSD License",
        "Programming Language :: Python :: 3",
        "Topic :: Software Development :: Libraries :: Python Modules",
    ]

### URLs subsection

Your project’s page on pypi.org can show a number of links, in addition to the `home-page` URL described above. You can point people to documentation or a bug tracker, for example.

This section is called `[tool.flit.metadata.urls]` in the file. You can use any names inside it. Here it is for flit:

    [tool.flit.metadata.urls]
    Documentation = "https://flit.pypa.io"

Added in version 1.0.

### Scripts section

A `[tool.flit.scripts]` table can be used along with `[tool.flit.metadata]`. It is in the same format as the newer `[project.scripts]` table described above.

### Entry points sections

`[tool.flit.entrypoints]` tables can be used along with `[tool.flit.metadata]`. They are in the same format as the newer `[project.entry-points]` tables described above.

## Sdist section

Added in version 2.0.

With no configuration, Flit can make an sdist with everything it needs to build and install your module: the package contents (including non-Python data files, but not `.pyc` bytecode files), your `pyproject.toml` file, the readme & license files given in the metadata, and the external data folder if you specified that.

If you want more control, you can give lists of paths or glob patterns as `include` and `exclude` in this section. For example:

    [tool.flit.sdist]
    include = ["doc/"]
    exclude = ["doc/*.html"]

These paths:

- Always use `/` as a separator (POSIX style)

- Must be relative paths from the directory containing `pyproject.toml`

- Cannot go outside that directory (no `../` paths)

- Cannot contain control characters or `<>:"\\`

- Can refer to directories, in which case they include everything under the directory, including subdirectories

- Should match the case of the files they refer to, as case-insensitive matching is platform dependent

Changed in version 3.8: Include and exclude patterns can now use recursive glob patterns (`**`).

Exclusions have priority over inclusions. Bytecode is excluded by default and cannot be included.

### Including files committed in git/hg

If you use flit build or flit publish, you can also make sdists with the files which are committed in version control (git or hg). This is a shortcut to e.g. include documentation source files, but not built HTML or PDF documentation. The include and exclude patterns are then applied on top of this list.

For now, including files from version control is the default for flit build and flit publish, and can be disabled with `--no-use-vcs`. The default will switch in a future version.

Using `flit_core` as a backend to other tools such as build never gets the list of files for the sdist from version control.

## External data section

Added in version 3.7.

Data files which your code will use should go inside the Python package folder. Flit will package these with no special configuration.

However, sometimes it’s useful to package external files for system integration, such as man pages or files defining a Jupyter extension. To do this, arrange the files within a directory such as `data`, next to your `pyproject.toml` file, and add a section like this:

    [tool.flit.external-data]
    directory = "data"

Paths within this directory are typically installed to corresponding paths under a prefix (such as a virtualenv directory). E.g. you might save a man page for a script as `(data)/share/man/man1/foo.1`.

Whether these files are detected by the systems they’re meant to integrate with depends on how your package is installed and how those systems are configured. For instance, installing in a virtualenv usually doesn’t affect anything outside that environment. Don’t rely on these files being picked up unless you have close control of how the package will be installed.

If you install a package with `flit install --symlink`, a symlink is made for each file in the external data directory. Otherwise (including development installs with `pip install -e`), these files are copied to their destination, so changes here won’t take effect until you reinstall the package.

Note

For users coming from setuptools: external data corresponds to setuptools’ `data_files` parameter, although setuptools offers more flexibility.