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Django + Postgres + Docker = :)

24 May, 2014 - 2 min read

Background

Early today I fucked-up a server of mine on accident, and I spent hours and hours setting everything backup. It sucked.

Most of that is a lie. I deleted a Docker image on accident, it was hosting a web reporting tool I had build for a client, which still kinda sucks, but isn't nearly as bad as it could of been, because I had the site back up in about 10 minutes. Here's why:

Docker Containers

The idea of Docker is mostly compared to containers in a shipyard. I like to envision myself walking down a grocery store isle, and checking things of a list:

  1. Database - needs to be relational... postgres, duh.
  2. Web App - django since I like python. I just built my own here.

Postgres Container

There are a few things to consider here:

  • Have postgres's data directory persist ouside the container. This way, if you're dumb like me and the container shuts down, the data isn't lost.
  • Linking containers is easy when running the parent container (here the Web App). The parent gets access to the child's env variables. For example, in my settings.py file to setup the connection to postgres I simply os.environ("DB_PORT_5432_TCP_PORT") and I have the port.

There are more things to consider, but since a database for a simple web app is really a commodity, I just need to worry about getting a few things right.

The Web App

Since I wrote this part. It's really as simple creating a Dockerfile in the repository then scripting out everything. Django is covered plenty of other places, but my Dockerfile looks something like:

FROM ubuntu:14.04

MAINTAINER trent@trenthauck.com

RUN apt-get -y update && \
    apt-get -y install python-pip && \
    apt-get -y install python-dev && \
    apt-get -y install libpq-dev

RUN pip install pandas django psycopg2 django_pandas

Plus some other things which I'd rather not share. And we're back, easy peasy.