Logging and monitoring in Ruby on Rails - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main purpose of logging in a Rails application?

Logging records important events and errors in the application to help developers understand what happened and diagnose issues.

beginner

Name two common types of logs generated by Rails.

1. Development logs - show detailed info during development.<br>2. Production logs - show important events and errors in live apps.

beginner

What is monitoring in the context of a Rails app?

Monitoring means watching the app’s health and performance over time to catch problems early and keep it running smoothly.

beginner

How can you view Rails logs in development mode?

You can see logs in the terminal where you run the Rails server or check the log/development.log file.

beginner

Why is it important to monitor error rates in a Rails app?

Because a sudden increase in errors can mean something is broken, so you can fix it quickly before users are affected.

Where are Rails logs stored by default?

A config/ directory

B log/ directory

C app/ directory

D public/ directory

Rails saves logs in the log/ directory, like log/development.log or log/production.log.

Which Rails component helps you write logs in your code?

A ActiveRecord

B ActionController

C ActionMailer

D Rails.logger

Rails.logger is used to write messages to the log files.

What does monitoring NOT typically include?

A Writing new features

B Watching error rates

C Tracking app performance

D Checking server health

Writing new features is development, not monitoring.

Which log level shows the most detailed information?

A DEBUG

B INFO

C ERROR

D WARN

DEBUG level logs show the most detailed info useful during development.

Why should production logs be less detailed than development logs?

A Because production logs are not important

B Because errors never happen in production

C To save disk space and improve performance

D To confuse attackers

Less detail in production logs helps save space and keeps the app fast.

Explain how logging and monitoring work together to keep a Rails app healthy.

Think about how logs are like a diary and monitoring is like a doctor checking the app’s health.

Describe how you would check for errors in a Rails app running in production.

Consider both manual log checking and automated monitoring.