Class: CircuitBreakage::Breaker

Inherits:
Object
  • Object
show all
Defined in:
lib/circuit_breakage/breaker.rb

Overview

A simple circuit breaker implementation. See the main README for usage details.

Direct Known Subclasses

RedisBackedBreaker

Constant Summary collapse

DEFAULT_FAILURE_THRESHOLD =

Number of failures required to trip circuit

5
DEFAULT_DURATION =

Number of seconds the circuit stays tripped

300
DEFAULT_TIMEOUT =

Number of seconds before the call times out

10
DEFAULT_ONLY_TRIP_ON =

Exceptions that trigger the breaker

[Exception]
DEFAULT_NEVER_TRIP_ON =

Exceptions that won’t trigger the breaker

[]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(block = nil) ⇒ Breaker

Returns a new instance of Breaker.



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# File 'lib/circuit_breakage/breaker.rb', line 21

def initialize(block=nil)
  self.block              = block
  self.failure_threshold  = DEFAULT_FAILURE_THRESHOLD
  self.duration           = DEFAULT_DURATION
  self.timeout            = DEFAULT_TIMEOUT
  self.only_trip_on       = DEFAULT_ONLY_TRIP_ON
  self.never_trip_on      = DEFAULT_NEVER_TRIP_ON
  self.failure_count      ||= 0
  self.last_failed        ||= 0
  self.state              ||= 'closed'
end

Instance Attribute Details

#block ⇒ Object

Returns the value of attribute block.



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# File 'lib/circuit_breakage/breaker.rb', line 11

def block
  @block
end

#duration ⇒ Object

Returns the value of attribute duration.



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# File 'lib/circuit_breakage/breaker.rb', line 12

def duration
  @duration
end

#failure_count ⇒ Object

Returns the value of attribute failure_count.



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# File 'lib/circuit_breakage/breaker.rb', line 11

def failure_count
  @failure_count
end

#failure_threshold ⇒ Object

Returns the value of attribute failure_threshold.



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# File 'lib/circuit_breakage/breaker.rb', line 12

def failure_threshold
  @failure_threshold
end

#last_exception ⇒ Object

Returns the value of attribute last_exception.



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# File 'lib/circuit_breakage/breaker.rb', line 12

def last_exception
  @last_exception
end

#last_failed ⇒ Object

Returns the value of attribute last_failed.



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# File 'lib/circuit_breakage/breaker.rb', line 11

def last_failed
  @last_failed
end

#never_trip_on ⇒ Object

Returns the value of attribute never_trip_on.



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# File 'lib/circuit_breakage/breaker.rb', line 13

def never_trip_on
  @never_trip_on
end

#only_trip_on ⇒ Object

Returns the value of attribute only_trip_on.



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# File 'lib/circuit_breakage/breaker.rb', line 13

def only_trip_on
  @only_trip_on
end

#state ⇒ Object

Returns the value of attribute state.



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# File 'lib/circuit_breakage/breaker.rb', line 11

def state
  @state
end

#timeout ⇒ Object

Returns the value of attribute timeout.



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# File 'lib/circuit_breakage/breaker.rb', line 12

def timeout
  @timeout
end

Instance Method Details

#call(*args, &block_arg) ⇒ Object

Yield the block within the circuit. If no block is passed use the block passed in at initialization



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# File 'lib/circuit_breakage/breaker.rb', line 35

def call(*args, &block_arg)
  case(state)
  when 'open'
    if time_to_retry?
      do_retry(*args, &block_arg)
    else
      raise CircuitOpen
    end
  when 'closed'
    do_call(*args, &block_arg)
  end
end