Deploying GeoDjango applications on heroku: Easy workthrough

Motivation

Recently, I was in the position to quickly prototype a location-based application. Since Django is pretty awesome for quick scaffolding with all other requirements still intact, I went straight for it using its extenstion GeoDjango¹. The development process was pretty interesting 😌. However, deploying the prototyped application on Heroku was a huge pain 😢 since resources were sparse and those available were seemingly outdated.

This guide tends to provide an updated workthrough to overcoming this hurdle.

Assumption

It is assumed that you have a GeoDjango¹ application available for deployment. If not, go through ¹ or Make a Location-Based Web App With Django and GeoDjango². Another assumption is that you have chosen to host your application on Heroku and your database is PostgreSQL.

Content

Let's get started. Having configured your application for Heroku deployment³, append the following to your settings.py file.

...
DATABASES['default']['ENGINE'] = 'django.contrib.gis.db.backends.postgis'

If you follow Django Tutorial Part 11: Deploying Django to production³, it should come directly after:

# Heroku: Update database configuration from $DATABASE_URL.
import dj_database_url
db_from_env = dj_database_url.config(conn_max_age=500)
DATABASES['default'].update(db_from_env)

The added code instructs Heroku to use a spatial database extension called postgis. In most cases, failure to include that line results in this error:

AttributeError: 'DatabaseOperations' object has no attribute 'geo_db_type'

Next, we need to add a custom buildpack to our project on heroku. By default, all Python applications are automatically given heroku/python official buildpack. However, since our application needs more than just a python runtime environment — our application needs GDAL, GEOS, and PROJ in addition to a python runtime environment — we must get the additional environment in place for our application to compile. There are various buildpacks out there for this, however Heroku Buildpack Geo worked seemlessly.

NOTE: It should be noted that this buildpack only provides the runtime environments for GIS related projects therefore, it cannot be used alone. You still need a python runtime environment for your applications to run.

Doing this is pretty easy with Heroku since it supports multiple buildpacks.

To add this custom buildpack — after you created your heroku application using heroku create application_name — follow the steps below:

Set the official python buildpack:
```
heroku buildpacks:set heroku/python
```
Insert the custom heroku-geo-buildpack:
```
heroku buildpacks:add --index 1 https://github.com/heroku/heroku-geo-buildpack.git
```
This will insert the heroku-geo-buildpack buildpack at the first position in the order of buildpack execution, and move the other buildpacks that are ahead of it down one position.⁴