How to run function in background in Django view

Question

I have Django project with one view. When I refresh page I want to call some function which is very complicated and take same time to execute. How and what is the best way to do it in backround?

import time
import psycopg2
from django.http import HttpResponse

def long_time_function(sec):
    time.sleep(sec)
    print('DONE')

def index(request):
   
    long_time_function(100)

    return HttpResponse('INDEX page')

There is some built in solutions to do that or I need to run this function with thread or multiprocessing and set Deamon = True ?

The function is deterministic?; and what are their parameters? Because if the result is the same, you must cache the result. — Jony_23, Apr 18 '22 at 17:30
Celery is a common method for dealing with background tasks https://realpython.com/asynchronous-tasks-with-django-and-celery/ and https://docs.celeryq.dev/en/stable/django/first-steps-with-django.html should get you started. Built in support is or near available: https://docs.djangoproject.com/en/4.0/topics/async/ — AMG, Apr 18 '22 at 18:36
@Jony_23 function parameters is different every time, I get it from POST method. And then in view check if method is post then run function, But in my case when function execution is long then page loads equaly function execution time. And this is what i want to avoid. When i get some params from POST method and submit form then function start execution but page reload imidiatelly and function run in bacground. (Function get data from from postgres and transform it to vectors) — Dmiich, Apr 18 '22 at 21:31
Does this answer your question? [Simple approach to launching background task in Django](https://stackoverflow.com/questions/21945052/simple-approach-to-launching-background-task-in-django) — Abdul Aziz Barkat, Nov 03 '22 at 07:08

score 1 · Accepted Answer · answered Apr 18 '22 at 19:56

1

Maybe you can take a look at the async support. async

answered Apr 18 '22 at 19:56

saro

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Super Kai - Kazuya Ito · Answer 2 · 2022-11-10T02:40:20.823

With asyncio, you can run multiple async functions in background concurrently and asynchronously in Django view as shown below.

# "store/views.py"

import asyncio
from django.http import HttpResponse

async def test1(num):
    print("Test1")
    return num + 1

async def test2(num):
    print("Test2")
    return num + 1

async def test(request):
    result1, result2 = await asyncio.gather(test1(2), test2(3))
    total = result1 + result2
    print(total) # 7
    return HttpResponse(total) # Return 7

This is the result below:

Test1
Test2
7
[03/Nov/2022 15:12:30] "GET /store/test/ HTTP/1.1" 200 1

And, with threads, you can also run multiple functions in background concurrently in Django view as shown below.

# "store/views.py"

from threading import Thread
from django.http import HttpResponse

def test1(num, r):
    print("Test1") 
    r[0] = num + 1

def test2(num, r):
    print("Test2")
    r[0] = num + 1

def call_tests_view(request):
    result1 = [None] # Here
    result2 = [None] # Here
    thread1 = Thread(target=test1, args=(2, result1), daemon=True)
    thread2 = Thread(target=test2, args=(3, result2), daemon=True)
    thread1.start()
    thread2.start()
    thread1.join()
    thread2.join()
    total = result1[0] + result2[0]
    print(total) # 7
    return HttpResponse(total) # Return 7

This is the result below:

Test1
Test2
7
[03/Nov/2022 15:16:45] "GET /store/test/ HTTP/1.1" 200 1

How to run function in background in Django view

2 Answers2