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Guides

Flask + Redis HTTP Server

This guide explains how to create and deploy a Flask app with a Redis database on Unikraft Cloud. The example consists of two services: a Flask web server that increments a page view counter stored in Redis.

To run this example, follow these steps:

1. Install the CLI. Use the unikraft CLI or the legacy kraft CLI. You need a BuildKit builder. The easiest way to get one is via Docker. Alternatively, you can also directly set up and use BuildKit, see the quick start.

2. Clone the examples repository and cd into the examples/httpserver-flask-redis directory:

Code
git clone https://github.com/unikraft-cloud/examples
cd examples/httpserver-flask-redis/

Make sure to log into Unikraft Cloud and pick a metro close to you. This guide uses fra (Frankfurt, 🇩🇪):

Deploy Redis

First, deploy the Redis instance. Redis is an internal service (not publicly accessible), reached via the redis.internal domain:

The output shows the Redis instance details:

Deploy Flask

Next, deploy the Flask web server. It connects to Redis using the REDIS_HOST and REDIS_PORT environment variables:

The output shows the Flask instance details:

In this case, the Flask instance address is https://withered-cherry-xfcrfp93.fra.unikraft.app. It's different for each run.

Test the deployment

Use curl to query the Flask instance. Each request increments the Redis counter:

Code
curl https://withered-cherry-xfcrfp93.fra.unikraft.app

Code
This webpage has been viewed 1 time(s)

Code
curl https://withered-cherry-xfcrfp93.fra.unikraft.app

Code
This webpage has been viewed 2 time(s)

You can list information about the instances by running:

Clean up

When done, remove the instances:

Learn more

Use the --help option for detailed information on using Unikraft Cloud:

Code
kraft cloud --help

Or visit the CLI Reference.