Spring Boot Actuator

Monitoring and managing applications in production is essential to ensure stability and performance. Spring Boot Actuator provides built-in features to track application health, metrics, and internal state through easy-to-use endpoints.

Exposes production-ready endpoints (like /actuator/health) to check application status
Supports monitoring via HTTP endpoints and JMX integration
Helps track metrics, performance, and system behavior for better management

Spring-Boot-Starter-Actuator_ — Spring Boot Starter Actuator

Advantages of Actuator Application

It increases customer satisfaction.
It reduces downtime.
It boosts productivity.
It improves Cybersecurity Management.
It increases the conversion rate.

1. Configuration for Actuator

In order to use hibernate validators, these configurations are necessary in your Spring Boot project.

1.1 Adding Actuator Dependency

To use the "Actuator", add the following dependency in your application’s project settings file.

For Maven (pom.xml):

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

For Gradle (build.gradle):

dependencies {
implementation 'org.springframework.boot:spring-boot-starter-actuator'
}

1.2 Configuring Actuator in application.properties

Actuator provides several configuration options to customize its behavior. Below are some common configurations:

We can also change the default endpoint by adding the following in the application.properties file.

management.endpoints.web.base-path=/details

Including IDs/Endpoints

By default, all IDs are set to false except for 'health'. To include an ID, use the following property in the application.properties file.

management.endpoint.<id>.enabled
Example -> management.endpoint.metrics.enabled=true

List down all IDs that we want to include which are separated by a comma.

management.endpoints.web.exposure.include=metrics,info

Include only metrics and info IDs and will exclude all others ('health' too).

To add/include all ID information about our application, we can do it in the application.properties file by simply adding the following

management.endpoints.web.exposure.include=*

Excluding IDs/Endpoints

To exclude an ID or endpoint, use the following property and list out the respective IDs separated by a comma in the application.properties file.

management.endpoints.web.exposure.exclude
Example -> management.endpoints.web.exposure.exclude=info

Project Folder Structure:

The below image demonstrates the picture of how your project must look:

2. Implementing the Project

2.1 Entity Class

UserEntity.java (Entity class representing the model data) is explained below:

This class acts as a simple java bean whose properties are returned as JSON response by the REST API's get() method.
'Lombok' library is used to generate GETTER/SETTER methods automatically at runtime using '@Data' annotation.
'@RequiredArgsConstructor' annotation is used to generate a zero-argument constructor and if final or '@NonNull' fields are present, then respective arguments constructor is created.
To add the 'Lombok' library in your application, add the following dependency in your application's project build.
'@Component' annotation is used so that this bean automatically gets registered in Spring's application context.

Implementation:

Java

package gfg;

import lombok.Data;
import lombok.RequiredArgsConstructor;
import org.springframework.stereotype.Component;

@Component
@Data
@RequiredArgsConstructor
public class UserEntity {
    String id = "1";
    String name = "Darshan.G.Pawar";
    String userName = "@drash";
    String email = "drash@geek";
    String pincode = "422-009";
}

2.2 Controller

RESTfulController.java (A REST API controller) for defining APIs and testing the program.

This controller's get() method uses the UserEntity bean to return JSON response. UserEntiy bean is outsourced through '@Autowired' annotation which was registered in Spring's application context.

Java

package gfg;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/get")
public class RESTfulController {

    @Autowired
    UserEntity entity;
  
    @GetMapping("/data") 
      public UserEntity getEntity(){
        return entity;
    }
}

3. Testing Actuator APIs

3.1 Controller APIs

Here, the JSON Formatter Chrome extension is used to automatically parse the JSON body. Further, it will be required to work with "Actuator".

3.2 Working with Spring Boot Actuator APIs

To access the 'Actuator' services, you will have to use the HTTP endpoint as it becomes reliable to work with.

3.2.1 /actuator

It's simple just hit the default endpoint '/actuator', ensure that your Application is running.

Example:

We can also change the default endpoint by adding the following in the application.properties file.

management.endpoints.web.base-path=/details

3.2.2 /actuator/health

We can click on these above links and see the respective information. Additionally, we can activate other Actuator IDs and use them after '/actuator' to see more information. For example, 'health' ID is activated by default. Therefore we can click the link in the image or directly use 'http://localhost:8080/actuator/health'.

'UP' means the application's health is good.

Commonly Used Actuator Endpoints

There are a total of 25 IDs out of which the commonly used are listed out below:

EndpointID	Description
beans	Displays a complete list of all the Spring beans in your application.
caches	Exposes available caches.
conditions	Shows conditions evaluated on configuration and auto-configuration classes.
health	Shows application health information.
httptrace	Displays HTTP trace information (last 100 requests).
loggers	Shows and modifies the configuration of loggers in the application.
mappings	Displays a collated list of all @RequestMapping paths.
sessions	Retrieves and deletes user sessions (requires Spring Session).
threaddump	Performs a thread dump.

3.2.3 /actuator/beans

3.2.4 /actuator/mappings

Including IDs/Endpoints