Scaling Ruby on Rails Applications: Techniques and Tools for Optimizing Performance - Part 5 (Monitoring and Logging)

As your Ruby on Rails application grows, it becomes important to monitor its performance and log its activities. This helps you identify and fix issues, and also gives you insights into how your application is being used. In this article, we will discuss how to implement monitoring and logging in Ruby on Rails, with code examples.

Monitoring

To monitor your Ruby on Rails application, you need to track its performance metrics such as response time, error rate, and throughput. One popular tool for monitoring Ruby on Rails applications is New Relic. New Relic offers a free plan that gives you access to basic monitoring features.

Here’s how you can integrate New Relic monitoring into your Ruby on Rails application:

Add the New Relic gem to your Gemfile:

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gem 'newrelic_rpm'

Install the gem:

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bundle install

Generate a New Relic configuration file:

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rails generate newrelic:config

Configure your New Relic license key in the config/newrelic.yml file:

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# config/newrelic.yml

common: &default_settings
  license_key: 'YOUR_LICENSE_KEY_HERE'

Start your application server:

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rails server

Visit your application in a web browser.

Log in to your New Relic account to view your application’s performance metrics.

Logging

Logging is the process of recording events and messages that occur in your application, such as error messages and user actions. This helps you troubleshoot issues and debug your application. Ruby on Rails provides a built-in logging framework that allows you to log messages to different output destinations, such as the console or a file.

Here’s an example of how to log messages to a file in your Ruby on Rails application:

Create a new logger in the config/environments/production.rb file:

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# config/environments/production.rb

Rails.application.configure do
  # ...

  # Create a new logger that logs to a file
  config.logger = ActiveSupport::Logger.new(
    File.join(Rails.root, 'log', 'production.log')
  )
end

Use the logger to log messages in your application code:

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# app/controllers/welcome_controller.rb

class WelcomeController < ApplicationController
  def index
    # Log a message
    Rails.logger.info('Hello, world!')
  end
end

View the log file in a text editor or console:

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tail -f log/production.log

Conclusion

Monitoring and logging are important techniques for maintaining and improving the performance and reliability of your Ruby on Rails application. With tools like New Relic and the built-in logging framework, you can easily monitor your application’s performance and log its activities, allowing you to quickly identify and fix issues.

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