Task status monitoring in Flask - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Check Flask task status endpoint output

Given a Flask app with a background task status endpoint, what is the output when the task is still running?

Flask

from flask import Flask, jsonify
app = Flask(__name__)
tasks = {'task1': 'running'}

@app.route('/status/<task_id>')
def status(task_id):
    state = tasks.get(task_id, 'not found')
    return jsonify({'task_id': task_id, 'status': state})

# Request: GET /status/task1

A {"task_id": "task1", "status": "running"}

B {"task_id": "task1", "status": "completed"}

C {"task_id": "task1", "status": "failed"}

D {"task_id": "task1", "status": "not found"}

💡 Hint

Check the tasks dictionary for the status of 'task1'.

The tasks dictionary has 'task1' with status 'running', so the endpoint returns that status in JSON.

❓ Configuration

intermediate

Configure Flask to run background tasks with status tracking

Which Flask extension and configuration is best suited to run background tasks and monitor their status?

A Use Flask-Mail to send task status emails

B Use Flask-Celery with Redis broker to run tasks and track status

C Use Flask-SocketIO with eventlet for real-time task status updates

D Use Flask-Login to authenticate task status requests

💡 Hint

Look for a task queue system integrated with Flask.

Flask-Celery with Redis is commonly used to run background tasks and track their status asynchronously.

❓ Troubleshoot

advanced

Troubleshoot missing task status updates in Flask app

A Flask app using Celery to run tasks does not update task status correctly. Which issue is most likely causing this?

A Redis server is running but not connected to Flask app

B Flask app is missing @app.route decorators

C The Celery worker is not running, so tasks never execute

D Flask debug mode is off

💡 Hint

If tasks never run, status won't update.

If the Celery worker process is not running, tasks are never executed and status remains unchanged.

🔀 Workflow

advanced

Order the steps to implement task status monitoring in Flask

Arrange these steps in the correct order to implement task status monitoring in a Flask app using Celery.

A 1,3,2,4

B 2,1,4,3

C 3,1,2,4

D 1,2,3,4

💡 Hint

Setup first, then task, then status route, then run worker.

First configure Celery, then create tasks, add status route, and finally start the worker to process tasks.

✅ Best Practice

expert

Choose the best practice for scalable task status monitoring in Flask

Which approach is best for scalable and reliable task status monitoring in a Flask app with many concurrent tasks?

A Use a persistent external store like Redis or database to save task status

B Log task status only to Flask console logs

C Send task status updates via email to users

D Store task status in Flask app memory (global variable) for quick access

💡 Hint

Think about multiple workers and app instances.

Using an external persistent store like Redis or a database ensures task status is consistent and accessible across multiple workers and app instances.