The document discusses the Circuit Breaker pattern, which protects applications from failures in external systems. It works by monitoring requests and switching between closed, open, and half-open states. When external systems are likely to fail, the circuit breaker will fail requests immediately instead of allowing them to fail and impact the application. Implementations of the pattern include Akka CircuitBreaker, Netflix Hystrix, and Apache Polygene's CircuitBreaker.

1. Microservices Pattern
Circuit Breaker
Septeni Techtalk - 01/2018
tung_nt

2. What’s Circuit Breaker?
● The Circuit Breaker pattern, popularized by Michael
Nygard in his book, Release It!
● The Circuit Breaker provides a way to guard your
application against faulty external systems.

3. How does it works?
● Closed: The request from the application is routed to the operation.
● Open: The request from the application fails immediately and an exception is returned to the
application.
● Half-Open: A limited number of requests from the application are allowed to pass through and
invoke the operation.

4. When to use this pattern?
● The operation is highly likely to fail.
○ Ex: remote API, external system/services, ...

5. Implementations
● Akka CircuitBreaker
● Netflix Hystrix
● Apache Polygene’s CircuitBreaker
● ...
● And your implementation

6. Akka CircuitBreaker Sample

7. Refs
● https://martinfowler.com/bliki/CircuitBreaker.html
● https://polygene.apache.org/java/latest/library-circuitbreaker.html
● https://doc.akka.io/docs/akka/current/common/circuitbreaker.html?la
nguage=scala

8. Thank you