gem bullet enable/disable for some paths/controllers

Selective Disabling of Bullet Gem for Performance Optimization

Learn how to strategically enable or disable the Bullet gem in your Ruby on Rails application, particularly for specific paths or controllers like ActiveAdmin, to balance N+1 query detection with performance needs.

The bullet gem is an invaluable tool for Ruby on Rails developers, designed to help identify and resolve N+1 query problems. While incredibly useful during development, running bullet in production or even in certain development environments (like when interacting with administrative interfaces such as ActiveAdmin) can sometimes introduce performance overhead or generate unnecessary warnings. This article will guide you through various strategies to selectively enable or disable bullet based on your application's needs, focusing on path-based and controller-based configurations.

Understanding Bullet's Configuration

The bullet gem provides a flexible configuration API that allows you to fine-tune its behavior. The primary configuration is typically done within an initializer file, often config/initializers/bullet.rb. By default, bullet is usually enabled in the development environment. However, for more granular control, you can leverage its skip_paths and only_paths options, or integrate it with controller-level logic.

# config/initializers/bullet.rb

if defined?(Bullet)
  Bullet.enable = true
  Bullet.alert = true
  Bullet.bullet_logger = true
  Bullet.console = true
  Bullet.rails_logger = true
  Bullet.add_footer = false

  # Example: Disable Bullet for specific paths
  # Bullet.skip_paths = ['/admin', '/api/v1']

  # Example: Only enable Bullet for specific paths
  # Bullet.only_paths = ['/users', '/products']
end

Basic Bullet gem configuration in an initializer.

Disabling Bullet for Specific Paths (e.g., ActiveAdmin)

One of the most common scenarios for selectively disabling bullet is for administrative interfaces like ActiveAdmin. These interfaces often perform complex queries that might trigger false positives or simply aren't a priority for N+1 optimization in the same way public-facing application features are. The skip_paths configuration option is perfect for this.

# config/initializers/bullet.rb

if defined?(Bullet)
  Bullet.enable = true
  # ... other configurations ...

  # Disable Bullet for ActiveAdmin paths
  Bullet.skip_paths = ['/admin']

  # You can add multiple paths:
  # Bullet.skip_paths = ['/admin', '/sidekiq']
end

Using skip_paths to disable Bullet for ActiveAdmin.

flowchart TD
    A[Request Arrives] --> B{Is Bullet Enabled?}
    B -- Yes --> C{Is Path in skip_paths?}
    C -- Yes --> D[Bullet Disabled for this Request]
    C -- No --> E[Bullet Enabled for this Request]
    B -- No --> D

Decision flow for Bullet's path-based enabling/disabling.

Enabling Bullet Only for Specific Paths

Conversely, you might want to enable bullet only for a very specific set of paths, perhaps when you're actively working on optimizing a particular feature. The only_paths option allows you to define an allowlist of paths where bullet should be active.

# config/initializers/bullet.rb

if defined?(Bullet)
  Bullet.enable = true
  # ... other configurations ...

  # Only enable Bullet for user-related paths
  Bullet.only_paths = ['/users', '/users/:id']

  # Note: If both skip_paths and only_paths are set, skip_paths takes precedence.
end

Using only_paths to enable Bullet for specific routes.

Controller-Level Control for More Granular Management

For even finer-grained control, you can enable or disable bullet directly within your controllers using before_action callbacks. This approach is particularly useful when you need to disable bullet for specific actions within a controller, or for an entire controller that doesn't fit a simple path-matching pattern.

# app/controllers/admin/dashboard_controller.rb

class Admin::DashboardController < ApplicationController
  before_action :disable_bullet, only: [:index, :show]

  def index
    # ... logic ...
  end

  def show
    # ... logic ...
  end

  private

  def disable_bullet
    Bullet.enable = false if defined?(Bullet)
  end
end

Disabling Bullet for specific actions within a controller.

Combining Strategies for Optimal Control

The most robust approach often involves combining these strategies. You might use skip_paths in your initializer for broad exclusions (like /admin) and then use controller-level disabling for specific edge cases or actions that require it. This layered approach ensures that bullet is active where it's most beneficial without causing unnecessary noise or performance hits elsewhere.

1. Configure Base Bullet Settings

Ensure your config/initializers/bullet.rb file has Bullet.enable = true and other desired global settings.

2. Apply Path-Based Exclusions

Use Bullet.skip_paths = ['/admin'] in your initializer to disable bullet for entire sections of your application, such as ActiveAdmin.

3. Implement Controller-Level Overrides (Optional)

For more specific control, define before_action callbacks in controllers to temporarily disable bullet for certain actions or entire controllers.

4. Test Thoroughly

Verify that bullet behaves as expected in both enabled and disabled sections of your application to ensure no N+1 queries are missed where they matter, and no false positives are generated where they don't.