How can I nicely print a formatted exception that I catch in a rescue block?

Question

I'm using Rails 5 (Ruby 2.4). I have a block of code that catches an exception and prints out, what I thought was a stack trace ...

      begin
    ...
      rescue Exception => e
        errors.push(e)
        puts "#{e.backtrace}"
        raise e
      end

Unfortunately what gets printed out is something completely unreadable, like below ...

["/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:202:in `block in wait_poll'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:193:in `loop'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:193:in `wait_poll'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:154:in `internal_poll'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:278:in `internal_poll'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:148:in `block in poll'", "/Users/nataliab/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0/monitor.rb:214:in `mon_synchronize'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:158:in `synchronize'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:148:in `poll'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:717:in `acquire_connection'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:490:in `checkout'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:364:in `connection'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:883:in `retrieve_connection'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/connection_handling.rb:128:in `retrieve_connection'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/connection_handling.rb:91:in `connection'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/relation/delegation.rb:43:in `connection'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/relation/query_methods.rb:105:in `bound_attributes'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/relation.rb:702:in `exec_queries'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/relation.rb:583:in `load'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/relation.rb:260:in `records'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/relation/finder_methods.rb:527:in `find_take'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/relation/finder_methods.rb:100:in `take'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/relation/finder_methods.rb:78:in `find_by'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/querying.rb:7:in `find_by'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/core.rb:187:in `find_by'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/activerecord-5.0.2/lib/active_record/dynamic_matchers.rb:65:in `find_by_name_and_day_and_user_id_and_distance_and_distance_unit_id'", "/Users/nataliab/Documents/workspace/myproject/app/services/abstract_import_service.rb:71:in `process_event_data'", "/Users/nataliab/Documents/workspace/myproject/app/services/running_in_the_usa_event_finder_service.rb:265:in `process_generic_event_link'", "/Users/nataliab/Documents/workspace/myproject/app/services/running_in_the_usa_event_finder_service.rb:118:in `process_event_link'", "/Users/nataliab/Documents/workspace/myproject/app/services/abstract_event_finder_service.rb:37:in `block (2 levels) in process_data'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/concurrent-ruby-1.0.5/lib/concurrent/executor/ruby_thread_pool_executor.rb:348:in `run_task'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/concurrent-ruby-1.0.5/lib/concurrent/executor/ruby_thread_pool_executor.rb:337:in `block (3 levels) in create_worker'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/concurrent-ruby-1.0.5/lib/concurrent/executor/ruby_thread_pool_executor.rb:320:in `loop'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/concurrent-ruby-1.0.5/lib/concurrent/executor/ruby_thread_pool_executor.rb:320:in `block (2 levels) in create_worker'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/concurrent-ruby-1.0.5/lib/concurrent/executor/ruby_thread_pool_executor.rb:319:in `catch'", "/Users/nataliab/.rvm/gems/ruby-2.4.0/gems/concurrent-ruby-1.0.5/lib/concurrent/executor/ruby_thread_pool_executor.rb:319:in `block in create_worker'"]

Is there any way I can get my exception printed out in a nice formatted way, the same way it woudl normally be printed out when it just occurs within Rails?

Answer 1

Try logging the exception message like this:

begin
  ...
rescue Exception => e
  logger.error e.message
  e.backtrace.each { |line| logger.error line }
end

Answer 2

I use awesome_print gem to get formatted output through Output console and in rails console mode.

group :development do
  gem 'awesome_print'
end

And then in Rails console, just append ap in front of any command, variable,hash or query.

> ap any_command_or_any_variable_or_query

and to output in through puts in code

ap e.backtrace

or

puts e.backtrace.ai

It is very Helpful when using with JSON data and API calls. Also error can be easily checked in formatted output