Docker – Jinja2 not rendering templates for Django in certain environments

I am using Django with Jinja2.

I have an issue where the Jinja2 template engine is not rendering templates on my local machine/Docker setup but the same code does render using Jinja2 on Github Codespaces.

The specific error is:

TemplateSyntaxError at /val/
Could not parse the remainder: '('valapp:engindex', args=[engagement.id])' from 'url('valapp:engindex', args=[engagement.id])'

My template settings in the settings.py file are:

TEMPLATES = [
    {
        "BACKEND": "django_jinja.backend.Jinja2",
        "DIRS": [
            os.path.join(BASE_DIR, 'templates')
        ],
        "APP_DIRS": True,
        "OPTIONS": {
            "environment": 'valuation.jinja2.environment',
        }
    },
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [os.path.join(BASE_DIR, 'templates')],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

I also have a jinja2.py file with the following code:

from django.contrib.staticfiles.storage import staticfiles_storage
from django.urls import reverse
from crispy_forms.utils import render_crispy_form
import os
from jinja2 import Environment, FileSystemLoader

custom_template_dir = "/workspaces/valapp/valapp/templates"    

def environment(**options):
    env = Environment(**options)
    env.globals.update({
        'static': staticfiles_storage.url,
        'crispy': render_crispy_form,
        'url': reverse,
    })
    env.loader = FileSystemLoader(custom_template_dir)
    return env

My requirements.txt file has the following:

asgiref==3.6.0
Django==4.1.7
pytz==2022.7.1
sqlparse==0.4.4
crispy-bootstrap4==2022.1
django-crispy-forms==2.0
django-jinja==2.10.2
Jinja2==3.1.2
psycopg2==2.9.5
click==8.1.3
reportlab==3.6.12

The Dockerfile has:

FROM python:3.10.11-alpine3.17

WORKDIR /app

COPY requirements.txt requirements.txt

RUN apk update

RUN apk add postgresql-dev gcc python3-dev musl-dev

RUN apk add --no-cache freetype-dev

RUN pip3 install -r requirements.txt

COPY . .

CMD ["python3", "manage.py", "runserver", "0.0.0.0:8000"]

I don’t understand why Django is using the Django template engine on my local/Docker setup but Jinja2 on Github Codespaces. Any guidance is much appreciated.