Circuit breaker pattern

A circuit breaker is a mechanism that is used to avoid a distributed application going down due to a cascading failure of many essential components. Circuit breakers help to avoid one failing component tearing down other dependent services in a domino effect. Like circuit breakers in an electrical system, which protect a house from burning down due to the failure of a malfunctioning plugged-in appliance by interrupting the power line, circuit breakers in a distributed application interrupt the connection from Service A to Service B if the latter is not responding or is malfunctioning. 

This can be achieved by wrapping a protected service call in a circuit breaker object. This object monitors for failures. Once the number of failures reaches a certain threshold, the circuit breaker trips. All subsequent calls to the circuit breaker will return with an error, without the protected call being made at all: