Writing custom endpoints in Spring Actuator

Hello! recently I had to write some custom endpoints using Spring Actuator in a little Spring Boot application, in this short but pragmatic post I will show two ways of writing custom endpoints.

Requirements / Configuration

First of all you need to make sure you have the following dependency in your pom.xml

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

Now we require some slight changes to our application.properties or application.yml, depends on what you are using.

I want to expose all the endpoints, for that I will the following configuration:

management.endpoints.web.exposure.include=*

But you can also expose individual beans:

management.endpoints.web.exposure.include=env,beans,metrics

With the above configuration, you should be able to see something like this if you go to your browser and check localhost:8080/actuator

Or you could also use HTTPie or curl:

HTTPie is really nice because it formats automatically the output :). With curl we had to use jq for that.

Note: If you have Spring Security in your classpath you will need extra configuration.

Using @Endpoint annotation

We simply need to use the @Endpoint annotation along with the @Component annotation to create a Spring-managed component.

import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
import org.springframework.boot.actuate.endpoint.annotation.ReadOperation;
import org.springframework.stereotype.Component;
 
@Component
@Endpoint(id = "say-hello")
public class SayHello {
 
    @ReadOperation
    public String say() {
        return "hello world";
    }
 
}