Introduction

This is an example setup of flask/uwsgi/nginx running in a docker container.

It is intended as a starting place for backend api services; the app supports JWT for authentication and CORS.

There are two dockerfiles:

flask-dockerfile: builds python, flask, uwsgi and nginx
- this is based on the phusion baseimage because flask needs both nginx and uwsgi processes to be running and the phusion baseimage provides an init system.
- if you want to configure your own setup, this is a good image to start with
- TODO: if there is a phusion image with a recent version (2.7.11) of python, should use that instead of building our own
api-website-dockerfile
- adds postgres support and sqlalchemy
- adds flask extensions for JWT and CORS
- configures nginx and uswsgi

The app itself is very basic. There are three endpoints:

POST /api/auth: uses the auth endpoint from https://pythonhosted.org/Flask-JWT/
GET /api/user/whoami: a protected endpoint that returns the username of the user corresponding to the sent authentication token
POST /api/user/register: register a new user

Usage

Build the images

$ cd dockerfiles
$ docker build -f flask-dockerfile -t flask .
$ docker build -f api-website-dockerfile -t flask-api .
$ cd ..

Setup the database

In order to run the app, a database needs to be setup; I like to use the postgres docker image:

$ docker run --name myapp-db -e POSTGRES_PASSWORD=mydbpassword -d -p 5432:5432 postgres

You'll want to create a new database and user, which can be done manually using psql:

$ psql -U postgres -p 5432 -h localhost <<EOF
CREATE USER dbuser WITH PASSWORD 'dbpwd';
CREATE DATABASE myapp WITH OWNER dbuser;
EOF

Run

Now, the app can be run, with the database linked in:

$ docker run --name myapp-api \
    --link myapp-db:postgres \
    -v $PWD/app:/app \
    -p 8080:80 \
    -e CONNECTION_STRING=postgresql://dbuser:dbpwd@postgres/myapp \
    -e SECRET_KEY=secretkey \
    flask-api

Test

You can create a new account and a corresponding access token using curl:

curl -H "Content-Type: application/json" \
    -X POST \
    -d '{"username":"john_doe","password":"xyz"}' \
    http://localhost:8080/api/user/register

And, to retrieve the username of the newly registered account

curl -H "Content-Type: application/json" \
     -H "Authorization: jwt <access_token>" \
    http://localhost:8080/api/user/whoami

Caveat

It is usually cautioned against rolling your own user-login related functionality but I did it anyway. I wanted something simple and couldn't find a library that didn't try to do to much.

Related Resources:

I use these flask extensions:

I should add SSL support:

https://github.com/certbot/certbot

This is a good reference if you're looking at doing something more complicated

https://pythonhosted.org/Flask-Security/

jobevers / flask-uwsgi-nginx-docker