Logging configuration in Flask - Mini Project: Build & Apply

Logging configuration

📖 Scenario: You are building a simple Flask web application. To keep track of what happens in your app, you want to set up logging. Logging helps you see messages about your app's activity, like errors or important events.

🎯 Goal: Set up basic logging in a Flask app to record messages with different severity levels. You will create a logger, configure its level, and log a test message.

📋 What You'll Learn

Create a Flask app instance named app

Set up a logger named app.logger

Configure the logger level to logging.INFO

Log an info message 'App started'

💡 Why This Matters

🌍 Real World

Logging is essential in real web applications to monitor app behavior, catch errors, and understand user activity.

💼 Career

Knowing how to configure logging in Flask is a basic skill for backend developers and DevOps engineers to maintain and troubleshoot web services.

1

Create a Flask app instance

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 instance.

2

Import logging and set logger level

Import the logging module, configure basic logging with logging.basicConfig(level=logging.INFO), and set the app.logger level to logging.INFO.

Flask

from flask import Flask
app = Flask(__name__)
# Import logging, configure basicConfig(level=logging.INFO), and set app.logger level to INFO
# Your code here

Need a hint?

Use logging.basicConfig(level=logging.INFO) and app.logger.setLevel(logging.INFO).

3

Log an info message

Use app.logger.info to log the message 'App started'.

Flask

from flask import Flask
import logging
logging.basicConfig(level=logging.INFO)
app = Flask(__name__)
app.logger.setLevel(logging.INFO)
# Log 'App started' as an info message
# Your code here

Need a hint?

Call app.logger.info('App started') to log the message.

4

Run the Flask app and see the log output

Add the code to run the Flask app only if the script is run directly. Use app.run(). When you run the app, the info log message 'App started' should appear in the console.

Flask

from flask import Flask
import logging
logging.basicConfig(level=logging.INFO)
app = Flask(__name__)
app.logger.setLevel(logging.INFO)
app.logger.info('App started')

# Run the app if this script is the main program
# Your code here

Need a hint?

Use the standard Python check if __name__ == '__main__': to run the app.