ActiveSupport::BacktraceCleaner

• activesupport/lib/active_support/backtrace_cleaner.rb

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.

• add_filter
• add_silencer
• clean
• new
• remove_silencers!

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, '') }

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/ }

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