# Boltons

*boltons should be builtins.*

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**Boltons** is a set of over 230 BSD-licensed, pure-Python utilities
in the same spirit as — and yet conspicuously missing from —
[the standard library][stdlib], including:

  * [Atomic file saving][atomic], bolted on with [fileutils][fileutils]
  * A highly-optimized [OrderedMultiDict][omd], in [dictutils][dictutils]
  * *Two* types of [PriorityQueue][pq], in [queueutils][queueutils]
  * [Chunked][chunked] and [windowed][windowed] iteration, in [iterutils][iterutils]
  * Recursive data structure [iteration and merging][remap], with [iterutils.remap][iterutils.remap]
  * Exponential backoff functionality, including jitter, through [iterutils.backoff][iterutils.backoff]
  * A full-featured [TracebackInfo][tbinfo] type, for representing stack traces,
    in [tbutils][tbutils]

**[Full and extensive docs are available on Read The Docs.][rtd]** See
what's new [by checking the CHANGELOG][changelog].

Boltons is tested against Python 3.7-3.14, as well as PyPy3.

[stdlib]: https://docs.python.org/3/library/index.html
[rtd]: https://boltons.readthedocs.org/en/latest/
[changelog]: https://github.com/mahmoud/boltons/blob/master/CHANGELOG.md

[atomic]: https://boltons.readthedocs.org/en/latest/fileutils.html#boltons.fileutils.atomic_save
[omd]: https://boltons.readthedocs.org/en/latest/dictutils.html#boltons.dictutils.OrderedMultiDict
[pq]: https://boltons.readthedocs.org/en/latest/queueutils.html#boltons.queueutils.PriorityQueue
[chunked]: https://boltons.readthedocs.org/en/latest/iterutils.html#boltons.iterutils.chunked
[windowed]: https://boltons.readthedocs.org/en/latest/iterutils.html#boltons.iterutils.windowed
[tbinfo]: https://boltons.readthedocs.org/en/latest/tbutils.html#boltons.tbutils.TracebackInfo

[fileutils]: https://boltons.readthedocs.org/en/latest/fileutils.html#module-boltons.fileutils
[ioutils]: https://boltons.readthedocs.org/en/latest/ioutils.html#module-boltons.ioutils
[dictutils]: https://boltons.readthedocs.org/en/latest/dictutils.html#module-boltons.dictutils
[queueutils]: https://boltons.readthedocs.org/en/latest/queueutils.html#module-boltons.queueutils
[iterutils]: https://boltons.readthedocs.org/en/latest/iterutils.html#module-boltons.iterutils
[iterutils.remap]: http://boltons.readthedocs.org/en/latest/iterutils.html#boltons.iterutils.remap
[iterutils.backoff]: http://boltons.readthedocs.org/en/latest/iterutils.html#boltons.iterutils.backoff
[tbutils]: https://boltons.readthedocs.org/en/latest/tbutils.html#module-boltons.tbutils

[remap]: http://sedimental.org/remap.html

## Installation

Boltons can be added to a project in a few ways. There's the obvious one:

```bash
pip install boltons
```
On macOS, it can also be installed via [MacPorts](https://ports.macports.org/port/py-boltons/summary):

```bash
sudo port install py-boltons
```


Then, [thanks to PyPI][boltons_pypi], dozens of boltons are just an import away:

```python
from boltons.cacheutils import LRU
my_cache = LRU()
```

However, due to the nature of utilities, application developers might
want to consider other options, including vendorization of individual
modules into a project. Boltons is pure-Python and has no
dependencies. If the whole project is too big, each module is
independent, and can be copied directly into a project. See the
[Integration][integration] section of the docs for more details.

[boltons_pypi]: https://pypi.python.org/pypi/boltons
[integration]: https://boltons.readthedocs.org/en/latest/architecture.html#integration

## Third-party packages

The majority of boltons strive to be "good enough" for a wide range of
basic uses, leaving advanced use cases to Python's [myriad specialized
3rd-party libraries][pypi]. In many cases the respective ``boltons`` module
will describe 3rd-party alternatives worth investigating when use
cases outgrow `boltons`. If you've found a natural "next-step"
library worth mentioning, see the next section!

[pypi]: https://pypi.python.org/pypi

## Gaps

Found something missing in the standard library that should be in
`boltons`? Found something missing in `boltons`? First, take a
moment to read the very brief [architecture statement][architecture]
to make sure the functionality would be a good fit. It covers the
design philosophy, what belongs in boltons, and how modules are
organized.

Then, if you are very motivated, submit [a Pull Request][prs]. Otherwise,
submit a short feature request on [the Issues page][issues], and we will
figure something out.

[architecture]: https://boltons.readthedocs.org/en/latest/architecture.html
[issues]: https://github.com/mahmoud/boltons/issues
[prs]: https://github.com/mahmoud/boltons/pulls

## Development

Install [uv](https://docs.astral.sh/uv/), then set up a dev environment:

```bash
uv venv && uv pip install -e .
```

Run the test suite (includes doctests):

```bash
uvx --with tox-uv tox -e py314
```

Run all environments in parallel:

```bash
uvx --with tox-uv tox -p auto
```
