Logging in production in Flask - Mini Project: Build & Apply

Logging in Production with Flask

📖 Scenario: You are building a simple Flask web application that will run in production. To keep track of what happens in your app, you need to set up logging. Logging helps you see errors and important events after your app is deployed.

🎯 Goal: Set up a basic logging system in a Flask app that writes messages to a file with a specific format. You will create the app, configure logging, add a log message when the home page is visited, and then print a confirmation message.

📋 What You'll Learn

Create a Flask app instance named app

Configure logging to write to a file named app.log

Set logging level to INFO

Use a log format that includes time, level, and message

Add a log message inside the home route when it is accessed

Print "Logging setup complete" at the end

💡 Why This Matters

🌍 Real World

Logging is essential in production apps to monitor behavior and troubleshoot issues after deployment.

💼 Career

Understanding how to set up and use logging in web applications is a key skill for DevOps and backend developers.

1

Create the Flask app

Import Flask from flask and create a Flask app instance called app.

Flask

# Import Flask and create app instance
# Your code here

Need a hint?

Use Flask(__name__) to create the app.

2

Configure logging to a file

Import logging and configure it to write logs to a file named app.log with level INFO and format showing time, level, and message.

Flask

from flask import Flask
app = Flask(__name__)

# Configure logging to file
# Your code here

Need a hint?

Use logging.basicConfig with filename, level, and format parameters.

3

Add a log message in the home route

Create a route for "/" using @app.route("/"). Define a function home that logs an INFO message "Home page accessed" using logging.info and returns the string "Welcome to the home page!".

Flask

from flask import Flask
import logging

app = Flask(__name__)

logging.basicConfig(filename='app.log', level=logging.INFO, format='%(asctime)s %(levelname)s: %(message)s')

# Create home route and add logging
# Your code here

Need a hint?

Use @app.route("/") to define the route and logging.info inside the function.

4

Print confirmation message

Write a print statement to display the text "Logging setup complete".

Flask

from flask import Flask
import logging

app = Flask(__name__)

logging.basicConfig(filename='app.log', level=logging.INFO, format='%(asctime)s %(levelname)s: %(message)s')

@app.route("/")
def home():
    logging.info("Home page accessed")
    return "Welcome to the home page!"

# Print confirmation message
# Your code here

Need a hint?

Use print("Logging setup complete") to show the message.