Tracer
Outputs a source level execution trace of a Ruby program.
It does this by registering an event handler with Kernel#set_trace_func for processing incoming events. It also provides methods for filtering unwanted trace output (see Tracer.add_filter, Tracer.on, and Tracer.off).
Installation
Add this line to your application's Gemfile:
gem 'tracer'
And then execute:
$ bundle
Or install it yourself as:
$ gem install tracer
Usage
Consider the following Ruby script
class A
def square(a)
return a*a
end
end
a = A.new
a.square(5)
Running the above script using ruby -r tracer example.rb
will output the following trace to STDOUT (Note you can also explicitly require 'tracer'
)
#0:<internal:lib/rubygems/custom_require>:38:Kernel:<: -
#0:example.rb:3::-: class A
#0:example.rb:3::C: class A
#0:example.rb:4::-: def square(a)
#0:example.rb:7::E: end
#0:example.rb:9::-: a = A.new
#0:example.rb:10::-: a.square(5)
#0:example.rb:4:A:>: def square(a)
#0:example.rb:5:A:-: return a*a
#0:example.rb:6:A:<: end
| | | | |
| | | | ---------------------+ event
| | | ------------------------+ class
| | --------------------------+ line
| ------------------------------------+ filename
---------------------------------------+ thread
Symbol table used for displaying incoming events:
+}+:: call a C-language routine
+{+:: return from a C-language routine
+>+:: call a Ruby method
+C+:: start a class or module definition
+E+:: finish a class or module definition
+-+:: execute code on a new line
+^+:: raise an exception
+<+:: return from a Ruby method
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
Bug reports and pull requests are welcome on GitHub at https://github.com/ruby/tracer.
License
The gem is available as open source under the terms of the 2-Clause BSD License.