Module: MasterSlaveSynchroniserMixin

Included in:
MasterSlaveSynchroniser
Defined in:
lib/buzzcore/extra/thread_utils.rb

Overview

This module decouples multiple master threads from multiple slave (worker) threads It provides two main methods : + master_attempt_command to be called by multiple clients with a command, returning a result or rasing an exception + slave_do_command to be called by worker threads with a block which processes the command.

see ProviderWorker in pay_server/app/pay_server.rb

Instance Method Summary collapse

Instance Method Details

#logger ⇒ Object 



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# File 'lib/buzzcore/extra/thread_utils.rb', line 327

def logger
  @logger || (@logger = Logger.new(STDERR))
end

#master_attempt_command(aCommand) ⇒ Object 



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# File 'lib/buzzcore/extra/thread_utils.rb', line 339

def master_attempt_command(aCommand)
	@semaphore.exclusive do
		command_sent = false
		begin
			before = Time.now
			logger.debug { "master sending aCommand:"+aCommand.inspect }
			@mvCommand.value = aCommand
			command_sent = true
			logger.debug { "master waiting for result" }
			result = @mvResponse.value
			logger.debug { "master received result:"+result.inspect }
		rescue Exception => e
			# exception causes thread critical status to be lost
			logger.debug { "master exception:"+e.inspect }
			if command_sent
				logger.debug { "rejecting" }
				@mvResponse.reject_value		#!!! this doesn't seem to return
			end
			raise e
		ensure
			logger.debug { "master_attempt_command: command_sent=#{command_sent.to_s} elapsed:"+(Time.now-before).to_s }
		end
		result
	end
end

#ms_synchronizer_initialize(aTimeout = nil, aLogger = nil) ⇒ Object 



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# File 'lib/buzzcore/extra/thread_utils.rb', line 331

def ms_synchronizer_initialize(aTimeout=nil,aLogger=nil)
	@logger = aLogger
	@semaphore = CountingSemaphore.new(1)
	timeout = aTimeout && aTimeout/2.0
	@mvCommand = MultiThreadVariable.new(nil,timeout)
	@mvResponse = MultiThreadVariable.new(timeout,nil)
end

#shutdown ⇒ Object 



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# File 'lib/buzzcore/extra/thread_utils.rb', line 378

def shutdown
	@mvCommand.unblock()
	@mvResponse.unblock()
end

#slave_do_command(&block) ⇒ Object 



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# File 'lib/buzzcore/extra/thread_utils.rb', line 365

def slave_do_command(&block)
	Thread.exclusive do
		logger.debug { "slave waiting for command" }
		command = @mvCommand.value
		logger.debug { "slave received command:"+command.inspect }
		result = yield(command)
		logger.debug { "slave sending result:"+result.inspect }
		@mvResponse.value = result
		logger.debug { "slave finished" }
		result
	end
end