Module: ScoutSemaphore

Defined in:
lib/scout/semaphore.rb

Defined Under Namespace

Classes: SemaphoreInterrupted

Constant Summary collapse

SEM_MUTEX = 
Mutex.new

Class Method Summary collapse

Class Method Details

.fork_each_on_semaphore(elems, size, file = nil) ⇒ Object 



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# File 'lib/scout/semaphore.rb', line 93

def self.fork_each_on_semaphore(elems, size, file = nil)

  TSV.traverse elems, :cpus => size, :bar => "Fork each on semaphore: #{ Misc.fingerprint elems }", :into => Set.new do |elem|
    elems.annotate elem if elems.respond_to? :annotate
    begin
      yield elem
    rescue Interrupt
      Log.warn "Process #{Process.pid} was aborted"
    end
    nil
  end
  nil
end

.synchronize(sem) ⇒ Object

Raises:



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# File 'lib/scout/semaphore.rb', line 66

def self.synchronize(sem)
  ret = ScoutSemaphore.wait_semaphore(sem)
  raise SemaphoreInterrupted if ret == -1
  begin
    yield
  ensure
    ScoutSemaphore.post_semaphore(sem)
  end
end

.thread_each_on_semaphore(elems, size) ⇒ Object 



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# File 'lib/scout/semaphore.rb', line 107

def self.thread_each_on_semaphore(elems, size)
  mutex = Mutex.new
  count = 0
  cv = ConditionVariable.new
  wait_mutex = Mutex.new

  begin

    threads = []
    wait_mutex.synchronize do
      threads = elems.collect do |elem| 
        Thread.new(elem) do |elem|

          continue = false
          mutex.synchronize do
            while not continue do
              if count < size 
                continue = true
                count += 1
              end
              mutex.sleep 1 unless continue
            end
          end

          begin
            yield elem
          rescue Interrupt
            Log.error "Thread was aborted while processing: #{Misc.fingerprint elem}"
            raise $!
          ensure
            mutex.synchronize do
              count -= 1
              cv.signal if mutex.locked?
            end
          end
        end
      end
    end

    threads.each do |thread| 
      thread.join 
    end
  rescue Exception
    Log.exception $!
    Log.info "Ensuring threads are dead: #{threads.length}"
    threads.each do |thread| thread.kill end
  end
end

.with_semaphore(size, file = nil) ⇒ Object 



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# File 'lib/scout/semaphore.rb', line 76

def self.with_semaphore(size, file = nil)
  if file.nil?
    file = "/scout-" << Misc.digest(rand(100000000000).to_s)[0..10] if file.nil?
  else
    file = file.gsub('/', '_') if file
  end

  begin
    Log.debug "Creating semaphore (#{ size }): #{file}"
    ScoutSemaphore.create_semaphore(file, size)
    yield file
  ensure
    Log.debug "Removing semaphore #{ file }"
    ScoutSemaphore.delete_semaphore(file)
  end
end