Class: Philiprehberger::Circuit::Breaker

Inherits:
Object
  • Object
show all
Includes:
Backoff, Callbacks, Execution, Metrics
Defined in:
lib/philiprehberger/circuit/breaker.rb

Overview

Circuit breaker with three states: closed, open, half-open

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Callbacks

#on_close, #on_half_open, #on_open, #on_reset

Methods included from Metrics

#metrics, #metrics_reset!

Constructor Details

#initialize(name, **opts) ⇒ Breaker

Returns a new instance of Breaker.

Parameters:

  • name (Symbol, String) —

    breaker name

  • threshold (Integer) —

    failures before opening

  • timeout (Numeric) —

    seconds before trying half-open

  • error_classes (Array<Class>) —

    exception classes to count

  • half_open_requests (Integer) —

    max probe requests in half-open

  • timeout_strategy (Symbol) —

    :fixed or :exponential

  • base_timeout (Numeric) —

    base timeout for exponential backoff

  • max_timeout (Numeric) —

    max timeout cap for exponential backoff



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# File 'lib/philiprehberger/circuit/breaker.rb', line 22

def initialize(name, **opts)
  @name = name
  @mutex = Mutex.new
  init_core_state(opts)
  init_callbacks
  init_metrics
  init_backoff_config(opts)
end

Instance Attribute Details

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/philiprehberger/circuit/breaker.rb', line 12

def name
  @name
end

Instance Method Details

#call(fallback: nil, &block) ⇒ Object

Execute a block with circuit protection



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# File 'lib/philiprehberger/circuit/breaker.rb', line 32

def call(fallback: nil, &block)
  @mutex.synchronize { handle_state(fallback, &block) }
end

#force_closed! ⇒ Object

Force circuit to closed state for maintenance; accepts all calls until reset



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# File 'lib/philiprehberger/circuit/breaker.rb', line 63

def force_closed!
  @mutex.synchronize do
    transition_to(CLOSED)
    @forced = true
  end
end

#force_open! ⇒ Object

Force circuit to open state for maintenance; rejects all calls until reset



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# File 'lib/philiprehberger/circuit/breaker.rb', line 55

def force_open!
  @mutex.synchronize do
    transition_to(OPEN)
    @forced = true
  end
end

#forced? ⇒ Boolean

Whether the breaker is in a manually forced state

Returns:

  • (Boolean) 


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# File 'lib/philiprehberger/circuit/breaker.rb', line 71

def forced?
  @mutex.synchronize { @forced }
end

#reset! ⇒ Object

Force circuit back to closed state



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# File 'lib/philiprehberger/circuit/breaker.rb', line 42

def reset!
  @mutex.synchronize do
    @forced = false
    transition_to(CLOSED)
  end
end

#state ⇒ Object

Current circuit state



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# File 'lib/philiprehberger/circuit/breaker.rb', line 37

def state
  @mutex.synchronize { @state }
end

#trip! ⇒ Object

Force circuit to open state (administrative trip)



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# File 'lib/philiprehberger/circuit/breaker.rb', line 50

def trip!
  @mutex.synchronize { transition_to(OPEN) }
end