Monitoring and error tracking in Django - Mini Project: Build & Apply

Monitoring and Error Tracking in Django

📖 Scenario: You are building a simple Django web application. To keep your app healthy and catch problems early, you want to add basic monitoring and error tracking.This will help you see when errors happen and understand your app's status.

🎯 Goal: Set up a basic error logging system in Django that records errors to a file and configure a simple health check view to monitor app status.

📋 What You'll Learn

Create a Django settings dictionary with logging configuration

Add a log file handler to capture errors

Write a health check view that returns HTTP 200 with a simple message

Print the log file path to confirm setup

💡 Why This Matters

🌍 Real World

Monitoring and error tracking help keep web applications reliable by alerting developers to problems quickly and providing data to fix issues.

💼 Career

Understanding how to configure logging and health checks is essential for DevOps roles and backend developers to maintain production systems.

1

Create basic logging configuration

Create a dictionary called LOGGING in Django settings with a version key set to 1 and an empty handlers dictionary.

Django

# Your code here

Hint

Start with a dictionary named LOGGING that has keys 'version' and 'handlers'.

2

Add a file handler for error logs

Add a file handler inside LOGGING['handlers'] with level set to 'ERROR', class set to 'logging.FileHandler', and filename set to 'django_error.log'.

Django

LOGGING = {
    'version': 1,
    'handlers': {
        # Add file handler here
    }
}
# Your code here

Hint

Inside handlers, add a file handler dictionary with the specified keys and values.

3

Configure loggers to use the file handler

Add a loggers dictionary to LOGGING with a 'django' logger that uses the 'file' handler and has level set to 'ERROR'.

Django

LOGGING = {
    'version': 1,
    'handlers': {
        'file': {
            'level': 'ERROR',
            'class': 'logging.FileHandler',
            'filename': 'django_error.log'
        }
    },
    # Add loggers here
}
# Your code here

Hint

Inside LOGGING, add a loggers dictionary with a 'django' key that uses the 'file' handler.

4

Create a health check view and print log file path

Create a Django view function called health_check that returns an HttpResponse with text 'OK'. Then, print the string 'Log file: django_error.log'.

Django

LOGGING = {
    'version': 1,
    'handlers': {
        'file': {
            'level': 'ERROR',
            'class': 'logging.FileHandler',
            'filename': 'django_error.log'
        }
    },
    'loggers': {
        'django': {
            'handlers': ['file'],
            'level': 'ERROR',
            'propagate': True
        }
    }
}

from django.http import HttpResponse

# Create health_check view below
# Print log file path below
# Your code here

Hint

Define a function health_check that returns HttpResponse('OK'). Then print the log file path string.

Practice

1. What is the main purpose of monitoring in a Django application?

easy

A. To design the user interface

B. To write new features for the app

C. To manage database migrations

D. To observe the app's performance and health in real time

Solution

1. Step 1: Understand monitoring concept

   Monitoring means watching how the app works live, checking speed, errors, and usage.

2. Step 2: Match purpose to options

   Only To observe the app's performance and health in real time talks about observing performance and health in real time, which matches monitoring.

3. Final Answer:

   To observe the app's performance and health in real time -> Option D

4. Quick Check:

   Monitoring = Real-time app observation [OK]

Hint: Monitoring = watching app health live [OK]

Common Mistakes:

• Confusing monitoring with coding features
• Thinking monitoring manages database
• Mixing monitoring with UI design

2. Which of the following is the correct way to install Sentry SDK for Django using pip?

easy

A. pip install sentry-sdk[django]

B. pip install sentry-django-sdk

C. pip install django-sentry

D. pip install sentry_sdk django

Solution

1. Step 1: Recall Sentry installation syntax

   Sentry SDK for Django is installed with extras syntax: sentry-sdk[django].

2. Step 2: Compare options

   Only pip install sentry-sdk[django] uses correct package name and extras format for Django integration.

3. Final Answer:

   pip install sentry-sdk[django] -> Option A

4. Quick Check:

   Correct pip install syntax = pip install sentry-sdk[django] [OK]

Hint: Use brackets for extras in pip install [OK]

Common Mistakes:

• Using wrong package names
• Missing brackets for extras
• Installing unrelated packages

3. Given this Django settings snippet for Sentry integration:

import sentry_sdk
from sentry_sdk.integrations.django import DjangoIntegration

sentry_sdk.init(
    dsn="https://[e-mail]/0",
    integrations=[DjangoIntegration()],
    traces_sample_rate=1.0,
    send_default_pii=True
)

What will happen when an error occurs in the Django app?

medium

A. The error will be ignored and not reported

B. The error will be sent to Sentry with user info and performance tracing

C. The app will crash without logging the error

D. Only performance data will be sent, no error details

Solution

1. Step 1: Analyze Sentry init parameters

   DSN is set, Django integration enabled, traces_sample_rate=1.0 means full performance tracing, send_default_pii=True sends user info.

2. Step 2: Understand error reporting behavior

   With this setup, errors and performance data including user info are sent to Sentry automatically.

3. Final Answer:

   The error will be sent to Sentry with user info and performance tracing -> Option B

4. Quick Check:

   Sentry setup sends errors + user info + traces [OK]

Hint: Full Sentry init sends errors and traces [OK]

Common Mistakes:

• Ignoring send_default_pii effect
• Confusing traces_sample_rate with error reporting
• Assuming errors are not sent automatically

4. You added Sentry to your Django project but no errors appear in your Sentry dashboard. Which is the most likely cause?

medium

A. You installed sentry-sdk but did not run migrations

B. You set traces_sample_rate to 0.5

C. You forgot to set the DSN in the sentry_sdk.init() call

D. You used the wrong Python version

Solution

1. Step 1: Identify key Sentry setup requirement

   DSN is required to send errors to the correct Sentry project.

2. Step 2: Evaluate options

   Without DSN, no errors are sent. Other options do not prevent error sending directly.

3. Final Answer:

   You forgot to set the DSN in the sentry_sdk.init() call -> Option C

4. Quick Check:

   Missing DSN = no error reports [OK]

Hint: Always set DSN to send errors [OK]

Common Mistakes:

• Thinking migrations affect Sentry error sending
• Confusing traces_sample_rate with error sending
• Blaming Python version without evidence

5. You want to monitor both errors and performance in your Django app using Sentry, but only want to sample 20% of transactions to reduce data volume. Which is the correct way to configure traces_sample_rate in sentry_sdk.init()?

hard

A. traces_sample_rate=0.2

B. traces_sample_rate=20

C. traces_sample_rate='20%'

D. traces_sample_rate=True

Solution

1. Step 1: Understand traces_sample_rate meaning

   It expects a float between 0.0 and 1.0 representing the fraction of transactions to sample.

2. Step 2: Match options to correct format

   0.2 means 20%, 20 or '20%' are invalid types, True is boolean not a fraction.

3. Final Answer:

   traces_sample_rate=0.2 -> Option A

4. Quick Check:

   Fraction 0.2 = 20% sampling [OK]

Hint: Use decimal fraction for sampling rate [OK]

Common Mistakes:

• Using integer or string instead of float
• Setting traces_sample_rate > 1
• Using boolean True instead of number