Python on Vercel

First, we’ll create a new directory for our Python app. We’ll call it clean-db-cron.

The database we’ll be using is Redis, so we’ll need to install the upstash_redis package.

mkdir clean-db-cron

cd clean-db-cron

pip install upstash-redis

Let’s write the Python code to clean up the database. We’ll use the upstash_redis package to connect to the database and delete all keys.

from upstash_redis import Redis

redis = Redis(url="https://YOUR_REDIS_URL", token="YOUR_TOKEN")

def delete_all_entries():
  keys = redis.keys("*") # Match all keys
  redis.delete(*keys)


delete_all_entries()

Try running the code to see if it works. Your database keys should be deleted!

In order to use QStash, we need to make the Python code into a public endpoint. There are many ways to do this such as using Flask, FastAPI, or Django. In this example, we’ll use the Python http.server module to create a simple HTTP server.

from http.server import BaseHTTPRequestHandler
from upstash_redis import Redis

redis = Redis(url="https://YOUR_REDIS_URL", token="YOUR_TOKEN")

def delete_all_entries():
  keys = redis.keys("*") # Match all keys
  redis.delete(*keys)


class handler(BaseHTTPRequestHandler):
  def do_POST(self):
    delete_all_entries()
    self.send_response(200)
    self.end_headers()

For the purpose of this tutorial, I’ll deploy the application to Vercel using the Python Runtime, but feel free to use any other hosting provider.

npm install -g vercel

vercel

Once deployed, you can find the public URL in the dashboard.

There are two ways we can go about configuring QStash. We can either use the QStash dashboard or the QStash API. In this example, it makes more sense to utilize the dashboard since we only need to set up a singular cronjob.

However, you can imagine a scenario where you have a large number of cronjobs and you’d want to automate the process. In that case, you’d want to use the QStash Python SDK.

To create the schedule, go to the QStash dashboard and enter the URL of the public endpoint you created. Then, set the schedule to run daily at a time of your choosing.

URL: https://your-vercel-app.vercel.app/api
Type: Scheduled
Every: every day at midnight (feel free to customize)

Once you start the schedule, QStash will invoke the endpoint at the specified time. You can scroll down and verify the job has been created!

from upstash_qstash import Client

client = Client("<QSTASH_TOKEN>")
schedules = client.schedules()
res = schedules.create({
  "destination": "https://YOUR_URL.vercel.app/api",
  "cron": "0 12 * * *",
})