Run events every given number of seconds

[freddyaboulton]

Description

Adds the every key word argument to the events so that they run every number of seconds.

Fixes: #2050

Demo

import math
import gradio as gr
import datetime
import plotly.express as px
import numpy as np


def get_time():
    return datetime.datetime.now()


plot_end = 2 * math.pi


def get_plot(period=1):
    global plot_end
    x = np.arange(plot_end - 2 * math.pi, plot_end, 0.02)
    y = np.sin(2*math.pi*period * x)
    fig = px.line(x=x, y=y)
    plot_end += 2 * math.pi
    return fig


with gr.Blocks() as demo:
    with gr.Row():
        with gr.Column():
            c_time2 = gr.Textbox(label="Current Time refreshed every second")
            gr.Markdown("Change the value of the slider to automatically update the plot")
            period = gr.Slider(label="Period of plot", value=1, minimum=0, maximum=10, step=1)
            plot = gr.Plot(label="Plot (updates every half second)")
        with gr.Column():
            name = gr.Textbox(label="Enter your name")
            greeting = gr.Textbox(label="Greeting")
            button = gr.Button(value="Greet")
            button.click(lambda s: f"Hello {s}", name, greeting)

    demo.load(lambda: datetime.datetime.now(), None, c_time2, every=1)
    dep = demo.load(get_plot, None, plot, every=0.5)
    period.change(get_plot, period, plot, every=0.5, cancels=[dep])

if __name__ == "__main__":
    demo.queue().launch()

Checklist:

• I have performed a self-review of my own code
• I have added a short summary of my change to the CHANGELOG.md
• My code follows the style guidelines of this project
• I have commented my code in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

A note about the CHANGELOG

Hello 👋 and thank you for contributing to Gradio!

All pull requests must update the change log located in CHANGELOG.md, unless the pull request is labeled with the "no-changelog-update" label.

Please add a brief summary of the change to the Upcoming Release > Full Changelog section of the CHANGELOG.md file and include
a link to the PR (formatted in markdown) and a link to your github profile (if you like). For example, "* Added a cool new feature by [@myusername](link-to-your-github-profile) in [PR 11111](https://github.com/gradio-app/gradio/pull/11111)".

If you would like to elaborate on your change further, feel free to include a longer explanation in the other sections.
If you would like an image/gif/video showcasing your feature, it may be best to edit the CHANGELOG file using the
GitHub web UI since that lets you upload files directly via drag-and-drop.

[github-actions]

All the demos for this PR have been deployed at https://huggingface.co/spaces/gradio-pr-deploys/pr-2512-all-demos

[abidlabs]

So cool! every and cancels are a nice combo!

[freddyaboulton]

Refactoring some of the code from the cancels PR so that it's easier to use in other parts of the codebase

[abidlabs]

Unrelated to your PR, this event trigger is missing many arguments, such as batch. It would be good to add if possible (or we can create a separate issue for it)

[freddyaboulton]

I'll do that in a separate PR! Thank you for pointing this out!

[abidlabs]

Suggested change

	every: int | None = None,
	every: float | None = None,

[abidlabs]

Suggested change

	def get_continuous_fn(fn, every):
	def continuous_fn(*args):
	called_before = False
	while True:
	output = fn(*args)
	if called_before:
	time.sleep(every)
	else:
	called_before = True
	yield output
	return continuous_fn
	def get_continuous_fn(fn, every):
	def continuous_fn(*args):
	while True:
	output = fn(*args)
	yield output
	time.sleep(every)
	return continuous_fn

Also, would it be better to use asyncio.sleep here instead of time.sleep so that the queue worker is free to do something else in the meantime?

[abidlabs]

Ah I see so you later avoid putting such events in the queue altogether because they don't get completed. So I'm not sure how much of a difference it makes to use asyncio.sleep but I do think it's probably better than having a background thread just sit there doing nothing

[freddyaboulton]

Lol love this refactor! Thank you.

Yea originally I had this as an async function but the problem with that is that you only want to sleep after the first function call. Tricky to implement without a generator and we don't currently support async generators. Will think about it though (may add async generators to #2552 )

[abidlabs]

This looks great @freddyaboulton! Tested it and works well, and plays nicely with cancels.

One suggestion would be to add some more documentation about it (maybe in this Guide?) since this is a pretty big feature. I would also mention somewhere that if you define an event that runs every seconds, this does not take into account the runtime of the function itself -- so a 2 second prediction function running with every=5 actually runs every 7 seconds.

Very excited about the possibilities this opens up!

[pngwn]

lgtm! Awesome work @freddyaboulton!