isabella232 / stack_frames

Zero allocation backtraces using MRI ruby’s profile frames API

StackFrames

This library allows backtraces to be captured and accessed without object allocations by leveraging MRI's profile frames API.

Installation

Add this line to your application's Gemfile:

gem 'stack_frames'

And then execute:

$ bundle

Or install it yourself as:

$ gem install stack_frames

Usage

Pre-allocate a buffer to use for capturing stack frames, then re-use that buffer to capture the backtrace multiple times.

# example.rb
require 'stack_frames'

STACK_FRAMES_BUFFER = StackFrames::Buffer.new(2)
CAPTURE_CALLER = -> { STACK_FRAMES_BUFFER.capture }

def foo(&block)
  yield
end

foo(&CAPTURE_CALLER)
caller_frame = STACK_FRAMES_BUFFER[1]
p caller_frame.path # => "example.rb"
p caller_frame.lineno # => 14
p caller_frame.method_name # => "foo"
puts

CAPTURE_CALLER.call
p caller_frame.path # => "example.rb"
p caller_frame.lineno # => 18
p caller_frame.method_name # => nil

# You can also search through the captured stack frames:
STACK_FRAMES_BUFFER.find { |frame| frame.path == "example.rb" } # => [the matching stack frame object]

If stack frames need to be captured in multiple threads, then access to the buffer can either be synchronized using a Mutex or a per-thread buffer could be created and stored in a thread-local variable.

Development

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

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

See our contributing guidelines for more information.

License

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