ruby_tracer
ruby_tracer is an extraction of ruby/debug
's powerful tracers, with user-facing APIs, IRB-integration, and improvements on accuracy.
Installation
$ bundle add ruby_tracer --group=development,test
If bundler is not being used to manage dependencies, install the gem by executing:
$ gem install ruby_tracer
Usage
Tracer.trace(object) { ... } # trace object's activities in the given block
Tracer.trace_call { ... } # trace method calls in the given block
Tracer.trace_exception { ... } # trace exceptions in the given block
Example
require "ruby_tracer"
obj = Object.new
def obj.foo
100
end
def bar(obj)
obj.foo
end
Tracer.trace(obj) { bar(obj) }
#depth:1 #<Object:0x000000010903c190> is used as a parameter obj of Object#bar at test.rb:13:in `block in <main>'
#depth:2 #<Object:0x000000010903c190> receives .foo at test.rb:10:in `bar'
ruby_tracer/helper
If you want to avoid the Tracer
namespace, you can do require "ruby_tracer/helper"
instead:
require "ruby_tracer/helper"
trace(object) { ... } # trace object's activities in the given block
trace_call { ... } # trace method calls in the given block
trace_exception { ... } # trace exceptions in the given block
IRB-integration
Once required, ruby_tracer
registers a few IRB commands to help you trace Ruby expressions:
trace Trace the target object (or self) in the given expression. Usage: `trace [target,] <expression>`
trace_call Trace method calls in the given expression. Usage: `trace_call <expression>`
trace_exception Trace exceptions in the given expression. Usage: `trace_exception <expression>`
Example
# test.rb
require "ruby_tracer"
obj = Object.new
def obj.foo
100
end
def bar(obj)
obj.foo
end
binding.irb
irb(main):001:0> trace obj, bar(obj)
#depth:23 #<Object:0x0000000107a86648> is used as a parameter obj of Object#bar at (eval):1:in `<main>'
#depth:24 #<Object:0x0000000107a86648> receives .foo at test.rb:10:in `bar'
=> 100
irb(main):002:0> trace_call bar(obj)
#depth:23> Object#bar at (eval):1:in `<main>'
#depth:24> #<Object:0x0000000107a86648>.foo at test.rb:10:in `bar'
#depth:24< #<Object:0x0000000107a86648>.foo #=> 100 at test.rb:10:in `bar'
#depth:23< Object#bar #=> 100 at (eval):1:in `<main>'
=> 100
Tracer Classes
If you want to have more control over individual traces, you can use individual tracer classes:
ObjectTracer
class User
def initialize(name) = (@name = name)
def name() = @name
end
def authorized?(user)
user.name == "John"
end
user = User.new("John")
tracer = ObjectTracer.new(user)
tracer.start do
user.name
authorized?(user)
end
#depth:3 #<User:0x000000010696cad8 @name="John"> receives #name (User#name) at test.rb:14:in `block in <main>'
#depth:3 #<User:0x000000010696cad8 @name="John"> is used as a parameter user of Object#authorized? at test.rb:15:in `block in <main>'
#depth:4 #<User:0x000000010696cad8 @name="John"> receives #name (User#name) at test.rb:8:in `authorized?'
ExceptionTracer
ExceptionTracer.new.start
begin
raise "boom"
rescue StandardError
nil
end
#depth:1 #<RuntimeError: boom> at test.rb:4
CallTracer
class User
def initialize(name) = (@name = name)
def name() = @name
end
def authorized?(user)
user.name == "John"
end
user = User.new("John")
tracer = CallTracer.new
tracer.start do
user.name
authorized?(user)
end
#depth:4 > block at test.rb:13
#depth:5 > User#name at test.rb:4
#depth:5 < User#name #=> "John" at test.rb:4
#depth:5 > Object#authorized? at test.rb:7
#depth:6 > User#name at test.rb:4
#depth:6 < User#name #=> "John" at test.rb:4
#depth:6 > String#== at test.rb:8
#depth:6 < String#== #=> true at test.rb:8
#depth:5 < Object#authorized? #=> true at test.rb:9
#depth:4 < block #=> true at test.rb:16
LineTracer
class User
def initialize(name) = (@name = name)
def name() = @name
end
def authorized?(user)
user.name == "John"
end
user = User.new("John")
tracer = LineTracer.new
tracer.start do
user.name
authorized?(user)
end
#depth:4 at test.rb:14
#depth:4 at test.rb:15
#depth:5 at test.rb:8
Customization
TBD
Acknowledgement
@ko1 (Koichi Sasada) implemented the majority of ruby/debug
, including its tracers. So this project wouldn't exist without his amazing work there.
Development
After checking out the repo, run bin/setup
to install dependencies. Then, run rake test-unit
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 the created tag, and push the .gem
file to rubygems.org.
Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/st0012/ruby_tracer. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.
License
The gem is available as open source under the terms of the MIT License.
Code of Conduct
Everyone interacting in the Ruby::Tracer project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.