Datetime

Python

There are two different kind of datetime in Python

Naive Datetime - datetime without timezone
Aware Datetime - datetime with timezone

Django Configuration

Always enable timezone support in Django settings.py

# django
USE_TZ = True
TIME_ZONE = "Asia/Bangkok"

# celery
CELERY_TIMEZONE = "Asia/Bangkok"

Datetime Comparison

When you are getting data from the database you will get the Aware Datetime. If you need to compare it with a Datetime object, it should be Aware Datetime object see below.

Get current datetime

Use timezone.now() or timezone.localtime over datetime.now()

import datetime

from django.utils import timezone

# Yes
now = timezone.now() # get current Aware datetime in UTC

now = timezone.localtime() # get current Aware datetime in Asia/Bangkok

# No
now = datetime.datetime.now() # get current Naive datetime

Convert Naive Datetime to Aware Datetime

import datetime

import pytz

# Yes
now = datetime.datetime.now() # current Naive datetime

tz = pytz.timezone("Asia/Bangkok")
aware_now = tz.localize(now)

# No
now = datetime.datetime.now() # current Naive datetime

tz = pytz.timezone("Asia/Bangkok")
aware_now = now.replace(tzinfo=tz) # return wrong datetime

Convert Aware Datetime to different timezone

from django.utils import timezone

import pytz

now = timezone.now() # current datetime in UTC

tz =  pytz.timezone("Asia/Bangkok")

bkk_now = now.astimezone(tz) # get current datetime in Asia/Bangkok