module ActiveSupport # 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. class BacktraceCleaner def initialize @filters, @silencers = [], [] end # Returns the backtrace after all filters and silencers has been run against it. Filters run first, then silencers. def clean(backtrace, kind = :silent) filtered = filter(backtrace) case kind when :silent silence(filtered) when :noise noise(filtered) else filtered end end # 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, '') } def add_filter(&block) @filters << block end # 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/ } def add_silencer(&block) @silencers << block end # 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. def remove_silencers! @silencers = [] end private def filter(backtrace) @filters.each do |f| backtrace = backtrace.map { |line| f.call(line) } end backtrace end def silence(backtrace) @silencers.each do |s| backtrace = backtrace.reject { |line| s.call(line) } end backtrace end def noise(backtrace) @silencers.each do |s| backtrace = backtrace.select { |line| s.call(line) } end backtrace end end end