Create custom Actuator endpoints

Spring Boot is known for being configurable, and that includes actuator endpoints! You can customize and enrich the existing endpoints as well as create completely new ones from scratch! How cool is that? ? It’s simpler than you might expect. Let’s see how it’s done.

Create a /release-notes Endpoint

The overall process is similar to creating an MVC controller method. We will create a class with a specific method, and then an annotated method which will return the actual response content. So create a class called  ReleaseNotesEndPoint, then annotate it with  @Component  and  @Endpoint(id="release-notes"). The id is the URL path of the endpoint. Then create a method that returns the actual release notes text. You need to annotate with @ReadOperation.

package com.dailycodebuffer.examples.SpringBootTutorial.config;

import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
import org.springframework.boot.actuate.endpoint.annotation.ReadOperation;
import org.springframework.stereotype.Component;

@Component
@Endpoint(id="release-notes")
public class ReleaseNotesEndpoint {
	
	String version10 = "** Version 1.0 ** \n\n"
			+ "* Homepage added \n"
			+ "* Item creation form added \n"
			+ "* View the watchlsit page added \n";
	
	@ReadOperation
	public String releaseNotes() {
		
		return version10;
	}
}

The endpoint is created but is not exposed yet, so let’s expose it like we did the other standard endpoints:

management.endpoints.web.exposure.include= *,release-notes

Now go to the  http://localhost:8081/actuator/release-notes  URL in your browser and see the release notes.

Make /release-notes navigable

We can always return the full history of release notes, but that could get unnecessarily big.  So let’s give the user the option of just seeing the release notes of a certain version.

We are going to add another method to our class, which will receive the version as a parameter. Based on that, it will return release notes of that version. The parameter should be annotated with  @Selector. Before that, create another class attribute called  version11, and add some features to it that we added later to the application. 

package com.dailycodebuffer.examples.SpringBootTutorial.config;

import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
import org.springframework.boot.actuate.endpoint.annotation.ReadOperation;
import org.springframework.boot.actuate.endpoint.annotation.Selector;
import org.springframework.stereotype.Component;

@Component
@Endpoint(id="release-notes")
public class ReleaseNotesEndpoint {

    String version10 = "** Version 1.0 ** \n\n"
            + "* Homepage added \n"
            + "* Item creation form added \n"
            + "* View the watchlsit page added \n";

    String version11 = "** Version 1.1 \n\n"
            + "* Reading from OMDb API added \n"
            + "* Actuator endpoints added \n";

    @ReadOperation
    public String releaseNotes() {

        return version11 + version10;
    }

    @ReadOperation
    public String selectReleaseNotes(@Selector String selector ) {
        if ("1.0".equals(selector)) return version10;
        else if ("1.1".equals(selector)) return version11;
        else return releaseNotes();
    }
}

Now if you go to http://localhost:8081/actuator/release-notes, you see the full release notes.

However, if you go to http://localhost:8081/actuator/release-notes/1.1, you will see the release notes of version 1.1.

You can find the complete source code on Github.