Always print the message, class, and backtrace when an exception is raised

require "backtrace_always"

def foo
  bar
end

def bar
  baz
end

def baz
  begin
	raise "some error brah brah"
  rescue => e
	puts "caught: #{e}"
  end
end

BacktraceAlways.enable!

foo  # backtrace to $stderr

BacktraceAlways.disable!

foo  # no backtrace to $stderr

BacktraceAlways { foo }  # within the block, backtrace to $stderr

BacktraceAlways.enable_inspect!

def div(n)
  10/n
end

begin
  div(0)
rescue => e
  p e  # prints the backtrace
end

BacktraceAlways.disable_inspect!

io = File.open("out.log", "w")
BacktraceAlways.output = io
BacktraceAlways { foo } # backtrace to io
io.close

BacktraceAlways.output = logger  # Will log at debug level

Bundler

gem "backtrace_always"

RubyGems

gem install backtrace_always

If TracePoint is available (Ruby >= 2 in most cases) all exceptions will have their backtrace printed (yes, even Exception sub classes).

If TracePoint is not available raise is overridden, and only explicit calls to it will print the backtrace. In this case exceptions raised by the Ruby interpreter will not have their backtrace printed.

By default BacktraceAlways acts like warn and will output to $stderr only if warnings are enabled. This can be changed by setting BacktraceAlways.output to the IO instance of your choosing.

To ease the pain of tracking down bugs in bad codebases.

Skye Shaw [skye.shaw {AT} gmail.com]

Copyright (c) 2015 Skye Shaw. Released under the MIT License.