celery-progress 0.0.12

Drop in, configurable, dependency-free progress bars for your Django/Celery applications.

Celery Progress Bars for Django

Drop in, dependency-free progress bars for your Django/Celery applications.

Super simple setup. Lots of customization available.

Demo

Celery Progress Bar demo on Build With Django

Github demo application: build a download progress bar for Django

Starting with Celery can be challenging, eeintech built a complete Django demo application along with a step-by-step guide to get you started on building your own progress bar!

Installation

If you haven't already, make sure you have properly set up celery in your project.

Then install this library:

pip install celery-progress

Usage

Prerequisites

First add celery_progress to your INSTALLED_APPS in settings.py.

Then add the following url config to your main urls.py:

from django.urls import re_path, include
re_path(r'^celery-progress/', include('celery_progress.urls')),  # the endpoint is configurable

Recording Progress

In your task you should add something like this:

from celery import shared_task
from celery_progress.backend import ProgressRecorder
import time

@shared_task(bind=True)
def my_task(self, seconds):
    progress_recorder = ProgressRecorder(self)
    result = 0
    for i in range(seconds):
        time.sleep(1)
        result += i
        progress_recorder.set_progress(i + 1, seconds)
    return result

You can add an optional progress description like this:

  progress_recorder.set_progress(i + 1, seconds, description='my progress description')

You can stop your task with an exception message like this:

  progress_recorder.stop_task(i + 1, seconds, 'my exception message')

Displaying progress

In the view where you call the task you need to get the task ID like so:

views.py

def progress_view(request):
    result = my_task.delay(10)
    return render(request, 'display_progress.html', context={'task_id': result.task_id})

Then in the page you want to show the progress bar you just do the following.

Add the following HTML wherever you want your progress bar to appear:

display_progress.html

<div class='progress-wrapper'>
  <div id='progress-bar' class='progress-bar' style="background-color: #68a9ef; width: 0%;">&nbsp;</div>
</div>
<div id="progress-bar-message">Waiting for progress to start...</div>

Import the javascript file.

display_progress.html

<script src="{% static 'celery_progress/celery_progress.js' %}"></script>

Initialize the progress bar:

// vanilla JS version
document.addEventListener("DOMContentLoaded", function () {
  var progressUrl = "{% url 'celery_progress:task_status' task_id %}";
  CeleryProgressBar.initProgressBar(progressUrl);
});

or

// JQuery
$(function () {
  var progressUrl = "{% url 'celery_progress:task_status' task_id %}";
  CeleryProgressBar.initProgressBar(progressUrl)
});

Displaying the result of a task

If you'd like you can also display the result of your task on the front end.

To do that follow the steps below. Result handling can also be customized.

Initialize the result block:

This is all that's needed to render the result on the page.

display_progress.html

<div id="celery-result"></div>

But more likely you will want to customize how the result looks, which can be done as below:

// JQuery
var progressUrl = "{% url 'celery_progress:task_status' task_id %}";

function customResult(resultElement, result) {
  $( resultElement ).append(
    $('<p>').text('Sum of all seconds is ' + result)
  );
}

$(function () {
  CeleryProgressBar.initProgressBar(progressUrl, {
    onResult: customResult,
  })
});

Customization

The initProgressBar function takes an optional object of options. The following options are supported:

Option	What it does	Default Value
pollInterval	How frequently to poll for progress (in milliseconds)	500
progressBarId	Override the ID used for the progress bar	'progress-bar'
progressBarMessageId	Override the ID used for the progress bar message	'progress-bar-message'
progressBarElement	Override the element used for the progress bar. If specified, progressBarId will be ignored.	document.getElementById(progressBarId)
progressBarMessageElement	Override the element used for the progress bar message. If specified, progressBarMessageId will be ignored.	document.getElementById(progressBarMessageId)
resultElementId	Override the ID used for the result	'celery-result'
resultElement	Override the element used for the result. If specified, resultElementId will be ignored.	document.getElementById(resultElementId)
onProgress	function to call when progress is updated	CeleryProgressBar.onProgressDefault
onSuccess	function to call when progress successfully completes	CeleryProgressBar.onSuccessDefault
onError	function to call on a known error with no specified handler	CeleryProgressBar.onErrorDefault
onTaskError	function to call when progress completes with an error	onError
onNetworkError	function to call on a network error (ignored by WebSocket)	onError
onHttpError	function to call on a non-200 response (ignored by WebSocket)	onError
onDataError	function to call on a 200 response that's not JSON or has invalid schema due to a programming error (ignored by WebSocket)	onError
onResult	function to call when returned non empty result	CeleryProgressBar.onResultDefault

WebSocket Support

This library has experimental WebSocket support using Django Channels courtesy of @EJH2.

A working example project leveraging WebSockets is available here.

To use WebSockets, install with pip install celery-progress[websockets,redis] or pip install celery-progress[websockets,rabbitmq] (depending on broker dependencies).

See WebSocketProgressRecorder and websockets.js for details.