Logging configuration in FastAPI - Mini Project: Build & Apply

Logging configuration

📖 Scenario: You are building a simple FastAPI 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 actions, errors, and important events.

🎯 Goal: Set up basic logging in a FastAPI app that writes messages to the console with a specific format.

📋 What You'll Learn

Create a logger named app_logger

Set the logging level to INFO

Configure the logger to output messages with the format: %(levelname)s:%(message)s

Log an INFO message saying App started

💡 Why This Matters

🌍 Real World

Logging is essential in real applications to monitor what the app is doing and to help find problems quickly.

💼 Career

Understanding logging setup is a key skill for DevOps and backend developers to maintain and troubleshoot applications.

1

Create a FastAPI app and import logging

Write code to import the FastAPI class from fastapi and the logging module. Then create a FastAPI app instance called app.

FastAPI

from fastapi import FastAPI
import logging

# Your code here

Need a hint?

Use from fastapi import FastAPI and app = FastAPI() to create the app.

2

Create a logger named app_logger and set level to INFO

Create a logger called app_logger using logging.getLogger with the name app_logger. Set its logging level to logging.INFO.

FastAPI

from fastapi import FastAPI
import logging

app = FastAPI()

# Your code here

Need a hint?

Use logging.getLogger('app_logger') and setLevel(logging.INFO).

3

Add a console handler with a simple message format

Create a StreamHandler for app_logger to output logs to the console. Set its format to %(levelname)s:%(message)s using a Formatter. Add this handler to app_logger.

FastAPI

from fastapi import FastAPI
import logging

app = FastAPI()

app_logger = logging.getLogger('app_logger')
app_logger.setLevel(logging.INFO)

# Your code here

Need a hint?

Create a StreamHandler, set its formatter, then add it to app_logger.

4

Log an INFO message 'App started'

Use app_logger.info to log the message 'App started'.

FastAPI

from fastapi import FastAPI
import logging

app = FastAPI()

app_logger = logging.getLogger('app_logger')
app_logger.setLevel(logging.INFO)

console_handler = logging.StreamHandler()
formatter = logging.Formatter('%(levelname)s:%(message)s')
console_handler.setFormatter(formatter)
app_logger.addHandler(console_handler)

# Your code here

Need a hint?

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