如何从Spring Boot Health端点获取某些字段

Question

I have successfully created a springboot app that returns all the basic endpoints. Now I want to return just few fields from that endpoint in my request. For instance, return status from /health page to my rest call. How do I filter this or make my rest call more specific?

The actual requirement is two return few fields from /env, /health of different apps in one call. For which I am able to do it by returning all fields for both env and health. I just need to return specific fields from them. Also can I use in memory json objects, if so how should I do it?

Answer 1

Finally I figured out as how to create it. So the incoming json object consists of fields in LinkedHashMap type. So I consumed its field values using key

LinkedHashMap response = (LinkedHashMap)restTemplate.getForObject("http://localhost:8080/env",Object.class);
EnvProperties variables = new EnvProperties (response);

Wrapper POJO for all fields,

public EnvProperties (LinkedHashMap body) {
   this.sysProperties = new SysEnvProperties((LinkedHashMap) body.get("systemProperties"));
 }

POJO for this field,

 public SysEnvProperties(LinkedHashMap body) {
   this.javaVersion = body.get("java.version").toString();
}

later creating a new json string

 @Override
 public String toString() {
  String s = null;
    try {
        s = mapper.writeValueAsString(this);
      } catch (JsonProcessingException e) {
          e.printStackTrace();
        }
      return s;
   }

I repeated the same for fields of interest, creating a POJO for each. Finally called these fields using similar wrapper class whose toString method returned the expected json object of desired fields only.

Answer 2

You can create Custom health endpoint or custom heath checker too.

For eg

@Component
public class CustomHealthCheck extends AbstractHealthIndicator {
    @Override
    protected void doHealthCheck(Health.Builder bldr) throws Exception {
        // TODO implement some check
        boolean running = true;
        if (running) {
          bldr.up();
        } else {
          bldr.down();
        }
    }
}

For further reading:

1. http://www.christianmenz.ch/programmieren/spring-boot-health-checks/
2. http://briansjavablog.blogspot.be/2017/09/health-checks-metric-s-more-with-spring.html
3. http://www.baeldung.com/spring-boot-actuators

Answer 3

You can find a tutorial here . However, the interfaces you want to look into implementing are:

org.springframework.boot.actuate.endpoint.Endpoint

Similar to creating a Controller. This is your /custom-health endpoint.

org.springframework.boot.actuate.metrics.CounterService

You can count integer-value metrics which will be available at /metrics .

org.springframework.boot.actuate.metrics.GaugeService

Or, you can measure double-value metrics which will be available at /metrics .

org.springframework.boot.actuate.health.HealthIndicator

Add metrics to the /health endpoint.