Dial

A modern profiler for your Rails application.

Utilizes vernier for profiling and prosopite for N+1 query detection.

[!NOTE] Check out the resources in the vernier project for more information on how to interpret the viewer, as well as comparisons with other profilers, including stackprof.

Installation

1. Add the gem to your Rails application's Gemfile:

gem "dial"

2. Install the gem:

bundle install

3. Mount the engine in your config/routes.rb file:

# this will mount the engine at /dial
mount Dial::Engine, at: "/dial"

4. (Optional) Configure the gem in an initializer:

# config/initializers/dial.rb

Dial.configure do |config|
  config.enabled = !Rails.env.production? # disable by default in production, use force_param to enable per request
  config.force_param = "profile" # override param name to force profiling
  if Rails.env.staging?
    config.sampling_percentage = 50 # override sampling percentage in staging for A/B testing profiler impact
  end
  unless Rails.env.development?
    config.storage = Dial::Storage::RedisAdapter # use Redis storage in non-development environments
    config.storage_options = { client: Redis.new(url: ENV["REDIS_URL"]), ttl: 86400 }
  end
  config.vernier_interval = 100
  config.vernier_allocation_interval = 10_000
  config.prosopite_ignore_queries += [/pg_sleep/i]
end

Options

Storage Backends

File Storage (Default)

Profile data is stored as files on disk with polled expiration. Only suitable for development and single-server deployments.

Dial.configure do |config|
  config.storage = Dial::Storage::FileAdapter
  config.storage_options = { ttl: 86400 }
end

Redis Storage

Profile data is stored in Redis with automatic expiration. Supports both single Redis instances and Redis Cluster.

# Single Redis instance
Dial.configure do |config|
  config.storage = Dial::Storage::RedisAdapter
  config.storage_options = { client: Redis.new(url: "redis://localhost:6379"), ttl: 86400 }
end

# Redis Cluster
Dial.configure do |config|
  config.storage = Dial::Storage::RedisAdapter
  config.storage_options = {
    client: Redis::Cluster.new(nodes: [
      "redis://node1:7000",
      "redis://node2:7001",
      "redis://node3:7002"
    ]),
    ttl: 86400
  }
end

Memcached Storage

Profile data is stored in Memcached with automatic expiration.

Dial.configure do |config|
  config.storage = Dial::Storage::MemcachedAdapter
  config.storage_options = { client: Dalli::Client.new("localhost:11211"), ttl: 86400 }
end

Comparison with rack-mini-profiler

Development

After checking out the repo, run bin/setup to install dependencies. Then, run bundle exec rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

Testing Storage Adapters

To test the Redis and Memcached storage adapters, you'll need running instances: docker compose -f docker-compose.storage.yml up

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/joshuay03/dial.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Dial project's codebase and issue tracker is expected to follow the code of conduct.