Repository has these applications;

/eureka -> Use the Service Registry to dynamically discover and call registered services. Developed by Netflix.

/hystrix-dashboard -> A latency and fault tolerance library. Developed by Netflix.

/custom-sample-api -> Provides sample data and registered to eureka. Can be called any application which fetchs registered services from it as http://remote-service.

/custom-sample-ui -> Circuit breaker pattern is implemented. All metrics can be discovered with Hystrix Dashboard. It calls custom-sample-api.

• JDK 1.8
• Apache Maven 3.5.4
• dotnet 2.1

cd /eureka
mvn -N io.takari:maven:wrapper
./mvnw spring-boot:run

cd /hystrix-dashboard
mvn install
java -jar target/hystrix-dashboard-0.0.1.BUILD-SNAPSHOT.jar

cd /custom-sample-api
dotnet run

cd /custom-sample-ui
dotnet run

Start UI application and run while true; do sleep 1; curl -s http://localhost:1923/api/home;echo -e '\r';done on terminal. Note: API is not running yet!

After executes less than 10 requests (circuitBreaker:RequestVolumeThreshold, default to 20) in 10 seconds (metrics:rollingStats:timeInMilliseconds, default to 10000 seconds), there won't be any decision to change the status. If fulfills the minimum threshold requirement and more than 80% of requests have failed (circuitBreaker:errorThresholdPercentage, default to 50), Hystrix will decide to open the Circuit Breaker.

When you see

Circuit Open

message on http://localhost:7979/hystrix/monitor?stream=http://localhost:1923/hystrix/hystrix.stream run the API immediately and wait until status changes!

• Netflix/Hystrix
• Steeltoe/Circuit Breaker
• Kubrynski - Overview of the circuit breaker in Hystrix