Installing Geospatial libraries in Docker - django

Question

Django's official documentation lists 3 dependencies needed to start developing PostGIS application. They list a table depending on the database.
I use docker for my local development and I am confused about which of those packages should be installed in the Django container and which in the PostgreSQL container. I am guessing some of them should be on both.
I would appreciate your help with this.

Answer 1

You need to install the Geospatial libraries only in the Django container because they are used for interacting with a spatially enabled DB (such as PostgreSQL with PostGIS). You can deploy such a DB by using as a base a ready-made image for that purpose, such as kartoza/postgis.
Here is a nice example of a Dockerfile that uses python:3.6-slim as a base and builds the GDAL dependencies into the container. The part of the Dockerfile that you need for that is the following:
FROM python:3.6-slim
ENV PYTHONUNBUFFERED=1
# Add unstable repo to allow us to access latest GDAL builds
# Existing binutils causes a dependency conflict, correct version will be installed when GDAL gets intalled
RUN echo deb http://deb.debian.org/debian testing main contrib non-free >> /etc/apt/sources.list && \
apt-get update && \
apt-get remove -y binutils && \
apt-get autoremove -y
# Install GDAL dependencies
RUN apt-get install -y libgdal-dev g++ --no-install-recommends && \
pip install pipenv && \
pip install whitenoise && \
pip install gunicorn && \
apt-get clean -y
# Update C env vars so compiler can find gdal
ENV CPLUS_INCLUDE_PATH=/usr/include/gdal
ENV C_INCLUDE_PATH=/usr/include/gdal
ENV LC_ALL="C.UTF-8"
ENV LC_CTYPE="C.UTF-8"
You can deploy both the Django app and the DB using docker-compose, using the following docker-compose.yaml (from the same repo as the Dockerfile):
# Sample compose file for a django app and postgis
version: '3'
services:
postgis:
image: kartoza/postgis:9.6-2.4
volumes:
- postgis_data:/var/lib/postgresql
environment:
ALLOW_IP_RANGE: 0.0.0.0/0
POSTGRES_PASS: ${POSTGRES_PASSWORD}
POSTGRES_USER: ${POSTGRES_USER}
POSTGRES_DB: postgis
web:
image: intelligems/geodjango:latest
command: python manage.py runserver 0.0.0.0:8000
environment:
DEBUG: "True"
SECRET_KEY: ${SECRET_KEY}
DATABASE_URL: postgresql://${POSTGRES_USER}:${POSTGRES_PASSWORD}#postgis:5432/postgis
SENTRY_DSN: ${SENTRY_DSN}
ports:
- 8000:8000
depends_on:
- postgis
volumes:
postgis_data: {}
In this repository, you can find more info and interesting bits of configuration for your issue: https://github.com/intelligems/docker-library/tree/master/geodjango (the Dockerfile snippet above is from that repo).
As a Note:
If you want to create a PostgreSQL with PostGIS enabled database as a "local DB" to interact with your local Django, you can deploy the previously mentioned kartoza/postgis:
Create a Volume:
$ docker volume create postgresql_data
Deploy the container:
$ docker run \
--name=postgresql-with-postgis -d \
-e POSTGRES_USER=user_name \
-e POSTGRES_PASS=user_pass \
-e ALLOW_IP_RANGE=0.0.0.0/0 -p 5433:5432 \
-v postgresql_data:/var/lib/postgresql \
--restart=always \
kartoza/postgis:9.6-2.4
Connect to the default DB (postgres) of the container and create your DB:
$ psql -h localhost -U user_name -d postgres
$ CREATE DATABASE database_name;
Enable PostGIS extension to the database:
$ \connect database_name
$ CREATE EXTENSION postgis;
This will result in a DB with the name database_name listening to port 5432 of your localhost and you can connect to that from your local Django app.