break on ctrl+c

[rriemann]

Hello,

I use Parallel.map to run some computations in parallel. Is it possible to trap ctrl+c or ctrl+d and break after current tasks are done? So far, the script stops entirely and my intermediate results are not saved.

[grosser]

you can do your own trapping and then raise a Parallel::Break
or check the presence of some file and then break ...

On Mon, Jul 25, 2016 at 2:09 PM, Robert Riemann notifications@github.com
wrote:

Hello,

I use Parallel.map to run some computations in parallel. Is it possible to
trap ctrl+c or ctrl+d and break after current tasks are done? So far, the
script stops entirely and my intermediate results are not saved.

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[rriemann]

I've tried something like this:

begin
  measurements = Parallel.map(measurements, progress: "Simulating") do |measurement|
    trap("SIGINT") { Parallel::Break }
    measurement[:cmd] = "java -jar app.jar --present-peers #{measurement[:presentPeers]} --deadline #{deadline} --byzantine-peers #{measurement[:byzantinePeers]} --seed #{measurement[:seed]} --log=jmsg.thres:error 2> /dev/null"
    measurement[:result] = `#{measurement[:cmd]}`.to_f
    measurement[:exitcode] = $?.to_i
    pp measurement
    measurement
  end
rescue Interrupt

end

However, when Parallel::Break is issued, the array measurements supposed to be fillled by Parallel.map is empty. :(

[grosser]

oh yeah ... break makes it return nil ... as rubies break does ...

should be able to use the finish hook ...

require 'parallel'
done = []
finish = lambda { |_,_,x| done << x; puts "DONE #{done.inspect}"  }
begin
  Parallel.each(Array.new(10), finish: finish) { |i| sleep 1; 2 }
rescue Interrupt
end
puts "end #{done.inspect}"

ruby xxx.rb
DONE [2]
DONE [2, 2]
DONE [2, 2, 2]
DONE [2, 2, 2, 2]
^CParallel execution interrupted, exiting ...
end [2, 2, 2, 2]