https://github.com/upkie/loop-rate-limiters

Loop rate limiters in Python with an API similar to rospy.Rate
https://github.com/upkie/loop-rate-limiters

python rate-limiting robotics rospy

Last synced: 2 months ago
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Loop rate limiters in Python with an API similar to rospy.Rate

• Host: GitHub
• URL: https://github.com/upkie/loop-rate-limiters
• Owner: upkie
• License: apache-2.0
• Created: 2022-12-02T14:27:06.000Z (about 2 years ago)
• Default Branch: main
• Last Pushed: 2024-08-29T06:59:11.000Z (4 months ago)
• Last Synced: 2024-11-01T18:16:19.749Z (2 months ago)
• Topics: python, rate-limiting, robotics, rospy
• Language: Python
• Homepage:
• Size: 4.08 MB
• Stars: 25
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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# Loop rate limiters

[![Build](https://img.shields.io/github/actions/workflow/status/upkie/loop-rate-limiters/main.yml?branch=main)](https://github.com/upkie/loop-rate-limiters/actions)

[![Documentation](https://img.shields.io/github/actions/workflow/status/upkie/loop-rate-limiters/docs.yml?branch=main&label=docs)](https://upkie.github.io/loop-rate-limiters/)

[![Coverage](https://coveralls.io/repos/github/upkie/loop-rate-limiters/badge.svg?branch=main)](https://coveralls.io/github/upkie/loop-rate-limiters?branch=main)

[![Conda version](https://img.shields.io/conda/vn/conda-forge/loop-rate-limiters.svg)](https://anaconda.org/conda-forge/loop-rate-limiters)

[![PyPI version](https://img.shields.io/pypi/v/loop-rate-limiters)](https://pypi.org/project/loop-rate-limiters/)

Simple loop frequency regulators in Python with an API similar to ``rospy.Rate``:

```python

from loop_rate_limiters import RateLimiter

from time import perf_counter

rate = RateLimiter(frequency=400.0)

while True:

    print(f"Hello from loop at {perf_counter():.3f} s")

    rate.sleep()

```

A similar ``AsyncRateLimiter`` class is available for [asynchronous code](https://github.com/upkie/loop-rate-limiters#asynchronous-io).

## Installation

### From conda-forge

```console

conda install -c conda-forge loop-rate-limiters

```

### From PyPI

```console

pip install loop-rate-limiters

```

## Asynchronous I/O

The ``AsyncRateLimiter`` class provides a loop frequency limiter for [asyncio](https://docs.python.org/3/library/asyncio.html):

```python

import asyncio

from loop_rate_limiters import AsyncRateLimiter

async def main():

    rate = AsyncRateLimiter(frequency=400.0)

    while True:

        loop_time = asyncio.get_event_loop().time()

        print(f"Hello from loop at {loop_time:.3f} s")

        await rate.sleep()

asyncio.run(main())

```

This can be used if, for instance, there are several tasks executed in parallel at different frequencies.

## See also

- [ischedule](https://github.com/aleksve/ischedule): single-thread interval scheduler in Python