Class: TryUntil::Repeatedly

Inherits:
Object
  • Object
show all
Defined in:
lib/try_until/repeatedly.rb

Overview

External interface Example: include TryUntil result = Repeatedly.new(Probe.new(Object.new, :to_s))

.attempts(5)
.interval(10)
.delay(120)
.rescues([ ArgumentError, IOError ])
.stop_when(lambda { |response| JSON.parse(response.body)['id'] == 'some_id' })
.log_to($stdout)

.execute

Not all of the above settings are required. These are the default values: attempts = 3 interval = 0 delay = 0 rescues = [] stop_when = lambda { |response| false } log_to = TryUntil::NullPrinter.new

Instance Method Summary collapse

Constructor Details

#initialize(probe) ⇒ Repeatedly

Returns a new instance of Repeatedly.



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# File 'lib/try_until/repeatedly.rb', line 24

def initialize(probe)
  @probe = probe
end

Instance Method Details

#attempts(int_num) ⇒ Object 



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# File 'lib/try_until/repeatedly.rb', line 28

def attempts(int_num)
  @attempts = int_num
  self
end

#configuration ⇒ Object 



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# File 'lib/try_until/repeatedly.rb', line 91

def configuration
  { :probe => @probe.to_s, :attempts => @attempts, :interval => @interval,
    :rescues => @rescues, :stop_when => @stop_when }
end

#delay(seconds) ⇒ Object 



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# File 'lib/try_until/repeatedly.rb', line 38

def delay(seconds)
  @delay = seconds
  self
end

#execute ⇒ Object

The heart of this gem: This method will repeatedly call ‘#sample’ on the subject and evaluate if the expectated result is returned. In case of errors it will rescue those and continue, provided the type of error is among the ones defined in @rescues.



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# File 'lib/try_until/repeatedly.rb', line 62

def execute
  @attempts = 3 unless @attempts
  @interval = 0 unless @interval
  @delay = 0 unless @delay
  @rescues = [] unless @rescues
  @stop_when = lambda { |response| false } unless @stop_when
  @log_to = NullPrinter.new unless @log_to

  Kernel.sleep(@delay) if @delay > 0
  count = 0
  while count < @attempts
    begin
      result = @probe.sample
      if @stop_when.call(result)
        log_outcome(count, 'CONDITION_MET')
        return result
      end
      log_outcome(count, 'CONDITION_NOT_MET')
    rescue *@rescues => exception
      log_outcome(count, exception.class)
      raise exception, "During final attempt (#{@attempts} configured) target returned #{exception}" if count + 1 == @attempts
    ensure
      count += 1
      Kernel.sleep @interval if @interval > 0
    end
  end
  raise "After #{@attempts} attempts, the expected result was not returned!"
end

#interval(seconds) ⇒ Object 



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# File 'lib/try_until/repeatedly.rb', line 33

def interval(seconds)
  @interval = seconds
  self
end

#log_to(io) ⇒ Object 



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# File 'lib/try_until/repeatedly.rb', line 53

def log_to(io)
  @log_to = io
  self
end

#rescues(errors) ⇒ Object 



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# File 'lib/try_until/repeatedly.rb', line 43

def rescues(errors)
  @rescues = errors
  self
end

#stop_when(callable) ⇒ Object 



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# File 'lib/try_until/repeatedly.rb', line 48

def stop_when(callable)
  @stop_when = callable
  self
end