What is the Circuit Breaker pattern, and how is it implemented in microservices?

The Circuit Breaker pattern helps prevent a failure in one part of the system from

cascading and affecting other parts of the system. It monitors requests to a service and trips

the circuit (i.e., stops further calls) when the service is deemed unhealthy.

• States of Circuit Breaker:

Follow :

• Closed: The circuit is "closed" and requests are passed through to the

service.

• Open: If the service fails repeatedly, the circuit "opens," and further requests

are not sent to the service, preventing additional strain.

• Half-Open: After a period of time, the circuit breaker enters a half-open state

and allows a few test requests to determine if the service is healthy again.

Implementation: Tools like Hystrix or Resilience4j can be used to implement circuit

breakers. These libraries allow you to specify when a circuit breaker should open based on

service failure rates or response times.

Example: If a Payment Service is down, the circuit breaker will prevent the Order Service

from continuously trying to contact it and instead return a fallback response, reducing strain

on the system.