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:

group :development do
  gem "dial"
end

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: "/" if Rails.env.development?

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

# config/initializers/dial.rb

Dial.configure do |config|
  config.vernier_interval = 100
  config.vernier_allocation_interval = 10_000
  config.prosopite_ignore_queries += [/pg_sleep/i]
end

Options

Option	Description	Default
vernier_interval	Sets the interval option for vernier.	200
vernier_allocation_interval	Sets the allocation_interval option for vernier.	2_000
prosopite_ignore_queries	Sets the ignore_queries option for prosopite.	[/schema_migrations/i]
content_security_policy_nonce	Sets the content security policy nonce to use when inserting Dial's script. Can be a string, or a Proc which receives env and response headers as arguments and returns the nonce string.	Rails generated nonce or nil

Comparison with rack-mini-profiler

	rack-mini-profiler	Dial
Compatibility	Any Rack application	Only Rails applications
Database Profiling	Yes	Yes (via vernier hook - marker table, chart)
N+1 Query Detection	Yes (*needs to be inferred)	Yes (via prosopite)
Ruby Profiling	Yes (with stackprof - flame graph)	Yes (via vernier - flame graph, stack chart, call tree)
Ruby Allocation Profiling	Yes (with stackprof - flame graph)	Yes (via vernier - flame graph, stack chart, call tree)
Memory Profiling	Yes (with memory_profiler)	Yes (*overall usage only) (via vernier hook - graph)
View Profiling	Yes	Yes (via vernier hook - marker table, chart)
Snapshot Sampling	Yes	No
Production Support	Yes	No

Note

SQL queries displayed in the profile are not annotated with the caller location by default. If you're not using the marginalia gem to annotate your queries, you will need to extend your application's ActiveRecord QueryLogs yourself.

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.

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.