Module: Hydra::Derivatives::Processors::ShellBasedProcessor::ClassMethods

Defined in:
lib/hydra/derivatives/processors/shell_based_processor.rb

Instance Method Summary collapse

Instance Method Details

#all_eof?(files) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/hydra/derivatives/processors/shell_based_processor.rb', line 103

def all_eof?(files)
  files.find { |f| !f.eof }.nil?
end

#execute(command) ⇒ Object 



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# File 'lib/hydra/derivatives/processors/shell_based_processor.rb', line 45

def execute(command)
  context = {}
  if timeout
    execute_with_timeout(timeout, command, context)
  else
    execute_without_timeout(command, context)
  end
end

#execute_with_timeout(timeout, command, context) ⇒ Object 



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# File 'lib/hydra/derivatives/processors/shell_based_processor.rb', line 54

def execute_with_timeout(timeout, command, context)
  begin
    status = Timeout::timeout(timeout) do
      execute_without_timeout(command, context)
    end
  rescue Timeout::Error => ex
    pid = context[:pid]
    Process.kill("KILL", pid)
    raise Hydra::Derivatives::TimeoutError, "Unable to execute command \"#{command}\"\nThe command took longer than #{timeout} seconds to execute"
  end

end

#execute_without_timeout(command, context) ⇒ Object 



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# File 'lib/hydra/derivatives/processors/shell_based_processor.rb', line 67

def execute_without_timeout(command, context)
  exit_status = nil
  err_str = ''
  stdin, stdout, stderr, wait_thr = popen3(command)
  context[:pid] = wait_thr[:pid]
  stdin.close
  stdout.close
  files = [stderr]

  until all_eof?(files) do
    ready = IO.select(files, nil, nil, 60)

    if ready
      readable = ready[0]
      readable.each do |f|
        fileno = f.fileno

        begin
          data = f.read_nonblock(BLOCK_SIZE)

          case fileno
            when stderr.fileno
              err_str << data
          end
        rescue EOFError
          Rails.logger "Caught an eof error in ShellBasedProcessor"
          # No big deal.
        end
      end
    end
  end
  exit_status = wait_thr.value

  raise "Unable to execute command \"#{command}\". Exit code: #{exit_status}\nError message: #{err_str}" unless exit_status.success?
end