ferios08 / flask-test-app

Flask Sample App

• Flask Sample App
  • Pre-requisite
  • Architecture & Command lines
  • Configuration
  • Endpoints
  • To Do & Questions
    • Build
    • Deployment

Pre-requisite

To run locally application, install docker and docker compose.

Run docker compose up -d to start app.

Check the following endpoints:

$ curl localhost:8080/-/healthy -w "%{http_code}"
{}
200
$ curl localhost:8080/-/ready -w "%{http_code}"
{}
200
$ curl localhost:8080/user -w "%{http_code}"
[...]
200

Architecture & Command lines

Application is made of:

• a Web Server for API Calls. The web server can be started with flask run --host 0.0.0.0 --port 8080
• migration script to confugure the database. The migration script can be run with flask db upgrade

Application needs a PostgreSQL database to run.

Configuration

The following environment variable allow to configure application:

• POSTGRES_USERNAME: username of PostgreSQL
• POSTGRES_PASSWORD: password of PostgreSQL
• POSTGRES_HOST: hostname or IP of PostgreSQL
• POSTGRES_PORT: listening port of PostgreSQL
• POSTGRES_DATABASE: name of the database

Endpoints

The following endpoints are available

• GET localhost:8080/-/healthy: return 200 when server is up
• GET localhost:8080/-/ready: return 200 when server is up
• GET localhost:8080/user: return list of users in database
• POST localhost:8080/user: create a user in database. The request must contain a body: {'username': 'my_username', 'email': 'my_email'}

To Do & Questions

Build

• Create a GitLab CI pipeline that build the docker image.
• Suggest improvement of this pipeline.
• Suggest optimizations on the Dockerfile

Deployment

• Create Helm chart templates to deploy application
  • A minimum of 2 pods are required for web server
  • don't forget to run migration scripts at deployment
  • After installation, the endpoint /user works well.
• Are liveness & readiness probes correctly implemented? Why?
• What improvement can be done in your Helm Chart?