Class: RServiceBus::CircuitBreaker

Inherits:
Object
  • Object
show all
Defined in:
lib/rservicebus/CircuitBreaker.rb

Overview

An implementation of Michael Nygard’s Circuit Breaker pattern.

Instance Method Summary collapse

Constructor Details

#initialize(host) ⇒ CircuitBreaker

Returns a new instance of CircuitBreaker.



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# File 'lib/rservicebus/CircuitBreaker.rb', line 22

def initialize( host )
    @host = host
    @maxNumberOfFailures = RServiceBus.getValue( 'RSBCB_MAX', 5 )
    @secondsToBreak = RServiceBus.getValue( 'RSBCB_SECONDS_TO_BREAK', 60 ).to_i
    @secondsToReset = RServiceBus.getValue( 'RSBCB_SECONDS_TO_RESET', 60 ).to_i
    @resetOnSuccess = RServiceBus.getValue( 'RSBCB_RESET_ON_SUCCESS', false )
    
    self.reset
end

Instance Method Details

#Broken ⇒ Object

Public Interface Broken will be called before processing a message.

=> Broken will be called before Failure



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# File 'lib/rservicebus/CircuitBreaker.rb', line 35

def Broken
    if !@timeToReset.nil? && Time.now > @timeToReset then
        self.reset
    end

    return @broken
end

#Failure ⇒ Object

This should be called less than success. If there is a failure, then taking a bit longer gives time to settle.



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# File 'lib/rservicebus/CircuitBreaker.rb', line 50

def Failure
    self.messageArrived


    ##logFirstFailure
    if @numberOfFailures == 0
        @numberOfFailures = 1
        @timeOfFirstFailure = Time.now
        @timeToBreak = @timeOfFirstFailure + @secondsToBreak
    else
        @numberOfFailures = @numberOfFailures + 1
    end


    ##checkToBreakCircuit
    if @numberOfFailures >= @maxNumberOfFailures then
        self.breakCircuit
    end
end

#Live ⇒ Object 



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# File 'lib/rservicebus/CircuitBreaker.rb', line 43

def Live
    return !self.Broken
end

#reset ⇒ Object 



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# File 'lib/rservicebus/CircuitBreaker.rb', line 12

def reset
    @broken = false

    @numberOfFailures = 0
    @timeOfFirstFailure = nil
    
    @timeToBreak = nil
    @timeToReset = nil
end

#Success ⇒ Object 



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# File 'lib/rservicebus/CircuitBreaker.rb', line 70

def Success
    if @resetOnSuccess == true then
        self.reset
        return
    end
    
    self.messageArrived
end