Spring Boot Actuator

Developing and managing an application are the two most important aspects of the application’s life cycle. It is very important to know what is going on beneath the application. Also, when we push the application into production, managing it gradually becomes critically important. Therefore, it is always recommended to monitor the application both during the development phase and at the production phase. 

For the same use case, Spring Boot provides an actuator dependency that can be used to monitor and manage your Spring Boot application. Spring Boot Actuator is a key feature of Spring Boot, and with the help of this, developers can manage their application easily. By /actuator and /actuator/health endpoints, we can achieve the purpose of monitoring.

• With the help of Spring Boot, we can achieve the above objectives.
• Spring Boot's Actuator dependency is used to monitor and manage the Spring web application.
• We can use it to monitor and manage the application with the help of HTTP endpoints or with JMX.

The image below demonstrates the structure of the 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:

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.

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:

3.2.3 /actuator/beans

3.2.4 /actuator/mappings

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

OR, we can just list down all IDs that you want to include which are separated by a comma.

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

This will 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=*

Output:

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

Use '*' in place of IDs in property to exclude all the IDs or endpoints.

Notes: 

1. Before setting the management.endpoints.web.exposure.include, ensure that the exposed actuators do not contain sensitive information.
2. They should be secured by placing them behind a firewall or are secured by something like Spring Security.