Many backtraces include too much information that‘s not relevant for the context. This makes it hard to find the signal in the backtrace and adds debugging time. With a BacktraceCleaner, you can setup filters and silencers for your particular context, so only the relevant lines are included.

If you need to reconfigure an existing BacktraceCleaner, like the one in Rails, to show as much as possible, you can always call BacktraceCleaner#remove_silencers!

Example: 

  bc = BacktraceCleaner.new
  bc.add_filter   { |line| line.gsub(Rails.root, '') }
  bc.add_silencer { |line| line =~ /mongrel|rubygems/ }
  bc.clean(exception.backtrace) # will strip the Rails.root prefix and skip any lines from mongrel or rubygems

Inspired by the Quiet Backtrace gem by Thoughtbot.

Methods
Public Class methods
new()

[ show source ]

    # File activesupport/lib/active_support/backtrace_cleaner.rb, line 18
18:     def initialize
19:       @filters, @silencers = [], []
20:     end
Public Instance methods
add_filter(&block)

Adds a filter from the block provided. Each line in the backtrace will be mapped against this filter.

Example: 

  # Will turn "/my/rails/root/app/models/person.rb" into "/app/models/person.rb"
  backtrace_cleaner.add_filter { |line| line.gsub(Rails.root, '') }

[ show source ]

    # File activesupport/lib/active_support/backtrace_cleaner.rb, line 33
33:     def add_filter(&block)
34:       @filters << block
35:     end
add_silencer(&block)

Adds a silencer from the block provided. If the silencer returns true for a given line, it‘ll be excluded from the clean backtrace.

Example: 

  # Will reject all lines that include the word "mongrel", like "/gems/mongrel/server.rb" or "/app/my_mongrel_server/rb"
  backtrace_cleaner.add_silencer { |line| line =~ /mongrel/ }

[ show source ]

    # File activesupport/lib/active_support/backtrace_cleaner.rb, line 44
44:     def add_silencer(&block)
45:       @silencers << block
46:     end
clean(backtrace)

Returns the backtrace after all filters and silencers has been run against it. Filters run first, then silencers.

[ show source ]

    # File activesupport/lib/active_support/backtrace_cleaner.rb, line 23
23:     def clean(backtrace)
24:       silence(filter(backtrace))
25:     end
remove_silencers!()

Will remove all silencers, but leave in the filters. This is useful if your context of debugging suddenly expands as you suspect a bug in the libraries you use.

[ show source ]

    # File activesupport/lib/active_support/backtrace_cleaner.rb, line 50
50:     def remove_silencers!
51:       @silencers = []
52:     end