Extend Metrics Health Checker Sample

What is Health Checker

Because micro-services is desgin by SRP(Single Responsibility Principle),one micro-service always depend on many components such as middle-ware like queue,database etc and other micro-services,so if one micro-service report failure,we want fast know what is the cause and more details to help us solve the problem.

Health check mechanism can let user write some logic to check components of micro-service dependent and return check result.

How to use

Add your checker implementation

Implement org.apache.servicecomb.foundation.metrics.health.HealthChecker interface:

public interface HealthChecker {
  String getName();

  HealthCheckResult check();
}

Then add the implementation class into META-INF.service.org.apache.servicecomb.foundation.metrics.health.HealthChecker by SPI(Service Provider Interface) way

In this demo,we had make two checkers :

1. CustomHealthChecker
   always return true checker
2. MySqlHealthChecker
   sim check mysql can connect checker

Add Dependency in POM

<dependency>
  <groupId>org.apache.servicecomb</groupId>
  <artifactId>metrics-core</artifactId>
  <version>{version}</version>
</dependency>

Start service

mvn spring-boot:run

Do check and get result

If you had config rest transport address in microservice.yaml like:

cse:
  rest:
    address: 0.0.0.0:7777

Then you can invoke http://{serverip}:7777/health get summary check result : true or false.

Only all registered health checker confirm isHealthy=true,the summary check result will be true,otherwise false

Also can invoke http://{serverip}:7777/health/details get details of each health checker reported.