Ruby script which tries to detect when mongo is up but super slow (for example due to IO issue) and stop it to allow fallback to secondary

mongo-hang-monitoring.rb

#!/usr/bin/env ruby

# Tries to detect when mongo is up but super slow  (ex: IO issue)

THRESHOLD = 20_000 # ms

def test_mongo tries: 5
  out = `echo -e "db.isMaster()\ndb.getReplicationInfo()" | mongo mongodb://localhost/?socketTimeoutMS=#{THRESHOLD} 2>&1`
  res = $?
  if res != 0 && !out['Connection refused']
    puts out
    if tries > 0
      sleep 20
      test_mongo tries: tries-1
    else
      puts "Mongo looks is dead, trying to stop it.."
      system("sudo service mongod stop")
      system("sudo service mongod status")
    end
  end
end

test_mongo