https://github.com/huy-dna/pasync

An async runtime for Python
https://github.com/huy-dna/pasync

Last synced: 22 days ago
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An async runtime for Python

• Host: GitHub
• URL: https://github.com/huy-dna/pasync
• Owner: Huy-DNA
• License: apache-2.0
• Created: 2024-05-28T16:18:14.000Z (5 months ago)
• Default Branch: main
• Last Pushed: 2024-05-29T03:43:26.000Z (5 months ago)
• Last Synced: 2024-05-29T07:38:43.599Z (5 months ago)
• Language: Python
• Size: 8.79 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# pasync - A simple event loop for async python

[![PyPI Version](https://img.shields.io/pypi/v/pasync.svg)](https://pypi.python.org/pypi/pasync)

This minimal package is mainly used to explore implementing an async runtime in Python.

## Installation

```bash

pip install pasync

```

## Usage

### Runner

The main construct that you'll often work with is `Runner`.

A runner is actually a wrapper around an event loop.

It comes with two flavors: non-blocking runner and blocking runner.

* A blocking runner will run all the tasks till end, blocking the main thread.

  When given a set of tasks, it will refuse to accept any task in the meaning time.

* A non-blocking runner will run all the tasks in another thread.

  Unlike a blocking runenr, it can accepts additional tasks in the meaning time.

By default, a runner is blocking.

* Blocking runner

  ```py

  async def gen_num(n):

    return n

  

  with Runner() as runner:

    assert runner.run_task(gen_num(1)) == 1

    assert runner.gather(gen_num(1), gen_num(2)) == [1, 2]

  ```

* Non-blocking runner

  ```py

  async def gen_num(n):

    return n

  

  with Runner(non_blocking = True) as runner:

    assert runner.run_task(gen_num(1)) == None             # Not support returning results yet

    assert runner.gather(gen_num(1), gen_num(2)) == None   # Not support returning results yet

  ```

### Promise

`Promise` is intended to simulate `Promise` in js. Its usage and semantics should be the same.

`Promise` itself is an awaitable, so it can be passed to `Runner.run_task`

`Promise.then` and `Promise.catch` return another promise.

## Pitfalls

1. Currently, non-blocking runner cannot return results of tasks yet.

   This can be worked around by making the top-level task return `None`, while all the subtasks's results are consumed inside the top-level task