Ideas

• Support for tests: https://github.com/jjb/ruby-clock/issues/38
• avoid mutex in shutdown https://github.com/jjb/ruby-clock/pull/41, https://github.com/jjb/ruby-clock/pull/42
• Support clockfile.rb (lowercase with the extension)
• Explore behavior of shutdown when shell commands are running
  • https://github.com/jjb/ruby-clock/commit/300de3f621bd72fcd106a12500b8c3055545329d
  • https://stackoverflow.com/questions/69653842/why-does-the-presence-of-a-forked-process-in-a-thread-change-the-behavior-of-sle
  • https://gist.github.com/lpar/1032297
  • https://github.com/kamstrup/command_runner_ng
  • https://www.ruby-forum.com/t/executing-system-commands-in-threads-under-ruby-1-8-6/175066
  • https://saveriomiroddi.github.io/Executing-and-killing-ruby-parallel-background-jobs/
• detect error condition in at_exit and log it and report it to the error reporter for example if a process dies because of out of memory

  class RunnerErrorReporter < Rails::Railtie
    def system_exit_reducer(error, count = 0)
      if 'exit' != error.message.strip || !error.cause
        [error, count]
      else
        system_exit_reducer(error.cause, count + 1)
      end
    end
  
    runner do
      at_exit do
        next unless $!
        next if SystemExit == $!.class && $!.success?
  
        # could start doing something like this, but first want to make sure
        # other cases are working as expected.
        # if SignalException == $!.class && 'SIGTERM' == $!.signm
        #   Rails.logger.info(received sigterm blah blah)
  
        error, system_exit_count = system_exit_reducer($!)
  
        custom_data = {
          invocation: `ps -p #{$PROCESS_ID} -o comm=`.strip,
          program_name: $PROGRAM_NAME,
          arguments: $*.join(" "),
          system_exit_count: system_exit_count,
          signal: [$!, error].map{ |e| e.try(:signm) }.join(', ')
        }
  
        ErrorReporter.track_exception(error, custom_data: custom_data, tags: ['runner'])
      end
    end
  end