Class: Object

Inherits:
BasicObject
Defined in:
lib/once_in.rb

Instance Method Summary collapse

Instance Method Details

#once_in(period, level = 0, scope = :global) ⇒ Object

Runs block once every ‘period` seconds

Parameters:

  • period (FixNum) —

    minimal number of seconds between code executions

  • level (FixNum) (defaults to: 0) —

    (0) which caller level should be used to separate execution contexts. For example if you call once_in from within a utility function and want to restrict it per utility function caller site you can use level = 1

  • scope (:global, :thread) (defaults to: :global) —

    When :thread it will keep separate execution context per thread



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# File 'lib/once_in.rb', line 9

def once_in period, level = 0, scope = :global
  # once per this key
  key = Kernel.caller[level]

  # find out last execution time
  last = case scope
  when :global
    (@@once_in_last_times ||= {})[key]
  when :thread
    (Thread.current[:once_in_last_times]  ||= {})[key]
  else
    raise "invlid scope #{scope.inspect}. valid scopes are :global and :thread"
  end

  now = Time.now.utc
  skip = last && (now - last )

  # run again if we didn't run yet, or we did it long time ago
  if !last || (now - last > period) 
    if :global == scope
      @@once_in_last_times[key] = now
    else
      Thread.current[:once_in_last_times][key] = now
    end
    yield
  end
end