Flask redis

Use this git repo as a reference implementation.

The above repo contains a .sb.yml file which is a specification of the entire app’s configuration. Check .sb.yml file for more information.

This will implement a simple endpoint in Flask which will increment a counter everytime the page is loaded in the browser.

It uses Redis to keep track of the count.

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Preparing your code

Fetch the Redis credentials from environment variables in the app.

import redis
from flask import Flask
redis_host = os.getenv('REDIS_HOST')
redis_password = os.getenv('REDIS_PASSWORD')
app = Flask(__name__)
cache = redis.Redis(host=redis_host, password=redis_password, port=6379)

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.sb.yml

env_vars:
  FLASK_APP: app.py
  FLASK_RUN_HOST: 0.0.0.0
  FLASK_RUN_PORT: "8080"

services:
  data-cache:
    type: redis
    attach_as: separate_variables

The environment variables are staple Flask environment variables needed to run your Flask app.

In addition to this, we create a redis service called data-cache and attach it to the app using separate variables.

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Procfile

We add a Procfile which is the idomatic way to run Flask apps.

web: flask run

Deploying this app will create a Flask server and a redis cache.