How do I log every method that's called in a Ruby program?
This is definitely possible -- in fact, there's even a method for it! Just add this somewhere in your code before the point that you want to start logging things:
set_trace_func proc { |event, file, line, id, binding, classname| printf "%8s %s:%-2d %10s %8s\n", event, file, line, id, classname}
The secret sauce you want comes from Kernel#set_trace_func
, as noted above:
- set_trace_func(proc) => proc
- set_trace_func(nil) => nil
Establishes
proc
as the handler for tracing, or disables tracing if the parameter isnil
.proc
takes up to six parameters: an event name, a filename, a line number, an object id, a binding, and the name of a class.proc
is invoked whenever an event occurs. Events are:c-call
(call a C-language routine),c-return
(return from a C-language routine),call
(call a Ruby method),class
(start a class or module definition),end
(finish a class or module definition),line
(execute code on a new line),raise
(raise an exception), andreturn
(return from a Ruby method). Tracing is disabled within the context of proc.
Here's a handy example:
class Test def test a = 1 b = 2 endendset_trace_func proc { |event, file, line, id, binding, classname| printf "%8s %s:%-2d %10s %8s\n", event, file, line, id, classname}t = Test.newt.test
(Note: don't try this in irb
unless you want a huge scrolling screen of text.) The resulting output is:
line test.rb:11 false c-call test.rb:11 new Class c-call test.rb:11 initialize Objectc-return test.rb:11 initialize Objectc-return test.rb:11 new Class line test.rb:12 false call test.rb:2 test Test line test.rb:3 test Test line test.rb:4 test Test return test.rb:4 test Test
You can play around with the formatting string above to get just the results you want to log (for example, it sounds like you're only interested in call
events). Hope that helps, and good luck with sorting through all those unit tests!
Recently, set_trace_func
was deprecated:
Note: this method is obsolete, please use TracePoint instead.
We can use TracePoint, which backs set_trace_func
, instead:
trace = TracePoint.new(:call) do |tp| puts "#{tp.defined_class}##{tp.method_id} got called (#{tp.path}:#{tp.lineno})"endtrace.enable# do stuff heretrace.disable
This is actually even more powerful than set_trace_func
because you can enable and disable at your convenience. You can selectively hook into the following events: :line, :class, :end, :call, :return, :c_call, :c_return, :raise, :b_call, :b_return, :thread_begin, :thread_end
Here a full example:
class MyClass def initialize end def y z end def z 1 + 1 endendtrace = TracePoint.new(:call) do |tp| puts "#{tp.defined_class}##{tp.method_id} got called (#{tp.path}:#{tp.lineno})"endtrace.enable # noteMyClass.new.ytrace.disable # MyClass#initialize got called (./trace.rb:4) # MyClass#y got called (./trace.rb:7) # MyClass#z got called (./trace.rb:10)
I wanted to include the seconds-past-the-minute the event happend at as well as how long was spent in each function
start = DateTime.now.strftime('%Q').to_i / 1000.0set_trace_func proc { |event, file, line, id, binding, classname| now_ms = DateTime.now.strftime('%Q').to_i / 1000.0 duration = '%.3f' % (now_ms - start) start = DateTime.now.strftime('%Q').to_i / 1000.0 printf "%s %s %8s %s:%-2d %10s %8s\n", DateTime.now.strftime("%S.%L"), duration, event, file, line, id, classname}AdminUser.create(password: "password", password_confirmation: "password", email: email)set_trace_func nil
I was trying to debug why it took so long to create users and log into ActiveAdmin.
05.761 0.000 c-return /Users/nperry/.rvm/gems/ruby-2.1.2@rxair/gems/bcrypt-3.1.7/lib/bcrypt/engine.rb:51 to_s String05.761 0.000 c-call /Users/nperry/.rvm/gems/ruby-2.1.2@rxair/gems/bcrypt-3.1.7/lib/bcrypt/engine.rb:51 __bc_crypt BCrypt::Engine09.736 63.975 c-return /Users/nperry/.rvm/gems/ruby-2.1.2@rxair/gems/bcrypt-3.1.7/lib/bcrypt/engine.rb:51 __bc_crypt BCrypt::Engine09.736 0.000 return /Users/nperry/.rvm/gems/ruby-2.1.2@rxair/gems/bcrypt-3.1.7/lib/bcrypt/engine.rb:59 hash_secret BCrypt::Engine09.736 0.000 c-call /Users/nperry/.rvm/gems/ruby-2.1.2@rxair/gems/bcrypt-3.1.7/lib/bcrypt/password.rb:46 new Class
And from that I know Ruby spent more than a minute in __bc_crypt
.