Synopsis

This project ties together Flask, Dash, Docker and Nginx for bootstraping CI\CD pipelines of Flask \ Dash \ Plot.ly Applications.

What is Dash?

Dash Web Applications combine the full power and best features of Plot.ly, Python, React.js and Flask.

https://dash.plot.ly/gallery

Quickstart

Clone the repository, cd into it and run

docker-compose build
docker-compose up -d

Preview

Point your browser to http://localhost:8000

Docker containers

For each component of this project a separate docker container is afforded, controlled ("orchestrated") by docker-compose.

For the sake of simplicity, the same image is used for the separate containers. The image stems from python:3.9.13-alpine, which contains a debian linux.

The are two containers in this project at work.

1. dash-auth-flask: where are Dash\Flask web application runs
2. nginx: containing the nginx server

dash-auth-flask/Dockerfile. This one Dockerfile includes all the necessary python components and their dependencies from dash-auth-flask/requirements.txt.

Because we're using the same image for multiple purposes like different flask applications it has to contain all of these components.

In an advanced use case you want to build different images which are tailored to their individual purposes.

For the nginx server container is out-of-the-box nginx image with flask/gunicorn re-write conf files.

docker-compose in development and production

To give an example of a development workflow with docker-compose two configuration files are used. A feature of docker-compose is to have multiple configuration files layered on top of each other where later files override settings from previous ones.

In this project the default docker-compose.yml runs the application in a production like manner while the additional docker-compose-development.yml runs the application in a way more suitable for development. "Production like" does actual mean that you can run it like this on the internet, check nginx configuration files included.

To run the application in a production like manner:

docker-compose up -d

This will start the docker containers defined in docker-compose.yml. It is equivalent to running

docker-compose -f docker-compose.yml up -d

To start the application in a development manner:

docker-compose -f docker-compose.yml -f docker-compose-development.yml up --build -d dash-auth-flask 

This will read the configuration from docker-compose.yml and include the changes stated in docker-compose-development.yml before running the containers. By this way we alter the configuration given in the first file by the configuration from the second.
Suppress --build option in various development scenarios:

docker-compose -f docker-compose.yml -f docker-compose-development.yml up -d dash-auth-flask

To kill all running docker processes:

docker-compose rm -fs

To build just the dev container

docker-compose -f docker-compose-development.yml build

To run just the dev container (http://localhost:8000)

docker-compose -f docker-compose-development.yml up -d

To tail the logs of either dev or prod containers

docker-compose logs -f

Networking

docker-compose automatically sets up local network for our service where the containers can talk to each other; usually in the 172.x.x.x range. It also ensures that containers can address each other by their names.

TODO

dash-bootstrap-components==0.13.1 needs to be updated to 1.1.0 but will require a refactor.