rack-mini-profiler

To use flamegraphs, add the stackprof gem to your Gemfile. You can then view flamegraphs using these methods:

1. Direct HTML response: Append ?pp=flamegraph to the URL or add the header X-Rack-Mini-Profiler: flamegraph.
2. Async Flamegraphs: Append ?pp=async-flamegraph to the URL. This returns your normal response (useful for JSON/XHR) and stores the data for later viewing via the 'flamegraph' link in the MiniProfiler UI or the X-MiniProfiler-Flamegraph-Path header.

To upgrade the speedscope files and assets used by rack-mini-profiler to the latest version, run the speedscope_upgrade rake task from the root directory of the repository. This task performs the following actions:

1. Downloads the latest speedscope release ZIP file from GitHub.
2. Removes existing files in the lib/html/speedscope directory.
3. Extracts the new ZIP file into lib/html/speedscope.
4. Modifies index.html to replace external Google Fonts links with local copies from the fonts directory, ensuring compatibility with intranet environments that lack third-party internet access.

bundle exec rake speedscope_upgrade

To use rack-mini-profiler in production environments, you must explicitly authorize requests to prevent unauthorized users from seeing profiling data. Use Rack::MiniProfiler.authorize_request within your application logic (e.g., in a controller callback) once you have verified the user's identity and permissions.

Warning: If your production application runs on multiple servers or dynos, you must configure the storage backend to use Redis or Memcache to ensure consistent profiling data across nodes.

# inside your ApplicationController

before_action do
  if current_user && current_user.is_admin?
    Rack::MiniProfiler.authorize_request
  end
end

Add the memory_profiler gem to your Gemfile. To generate a report, append ?pp=profile-memory to your request URL.

You can use the following query parameters to filter results (using regular expressions):

• memory_profiler_allow_files: Filename pattern to include (default: all).
• memory_profiler_ignore_files: Filename pattern to exclude (default: none).
• memory_profiler_top: Number of results per section (default: 50).

Example: ?pp=profile-memory&memory_profiler_allow_files=active_record|app

Alternative memory tools (no extra gem required):

• ?pp=profile-gc: Report Garbage Collection statistics.
• ?pp=analyze-memory: Report ObjectSpace statistics.

SPAs (Ember, Angular, etc.) require manual handling because routes change without full page loads.

1. On route transition: Call window.MiniProfiler.pageTransition() to clear old profiling data and statistics.
2. Inject Speed Badge: Manually inject the MiniProfiler <script> tag into your application. Note that the data-version GUID and the ?v= parameter must match the current release of rack_mini_profiler to ensure the latest assets are fetched.

// Call this on every SPA route transition
if (window.MiniProfiler !== undefined) {
  window.MiniProfiler.pageTransition();
}

Rack Builder

require 'rack-mini-profiler'
use Rack::MiniProfiler

Sinatra

require 'rack-mini-profiler'
class MyApp < Sinatra::Base
  use Rack::MiniProfiler
end

Hanami

For Hanami, use Rack integration and manually register the rendering method to be profiled:

# config.ru
require 'rack-mini-profiler'
Rack::MiniProfiler.profile_method(Hanami::View::Rendering::Partial, :render) { "Render partial" }
use Rack::MiniProfiler

To run the test suite, you must have Memcached and Redis services running. Use the following commands to build and run the specs.

$ bundle exec rake build
$ bundle exec rake spec

When using Heroku Redis in production, you may need to configure storage_options with specific SSL parameters to avoid connection issues.

if Rails.env.production?
  Rack::MiniProfiler.config.storage_options = {
    url: ENV["REDIS_URL"],
    ssl_params: { verify_mode: OpenSSL::SSL::VERIFY_NONE }
  }
  Rack::MiniProfiler.config.storage = Rack::MiniProfiler::RedisStore
end

Add rack-mini-profiler to your Gemfile for Ruby 3.2+.

Important: To ensure SQL instrumentation works, you must require rack_mini_profiler below your database gems (like pg or mysql2) in the Gemfile.

To enable advanced profiling features, include these optional gems:

• Memory profiling: gem 'memory_profiler'
• Call-stack flamegraphs: gem 'stackprof'

gem 'rack-mini-profiler'