Spring Boot Actuator

Spring Boot Actuator is a powerful feature that helps monitor and manage Spring Boot applications in production. It provides built-in endpoints to check the application’s health, metrics, environment properties, and more.

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1. Adding Actuator to a Spring Boot Application

To enable Actuator, add the following dependency to your pom.xml (for Maven):

xml

<dependency>

    <groupId>org.springframework.boot</groupId>

    <artifactId>spring-boot-starter-actuator</artifactId>

</dependency>

For Gradle:

groovy

implementation ‘org.springframework.boot:spring-boot-starter-actuator’

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2. Configuring Actuator Endpoints

By default, only the /actuator/health and /actuator/info endpoints are enabled. You can expose more endpoints in the application.properties or application.yml file.

Enable All Endpoints

properties

management.endpoints.web.exposure.include=*

Enable Specific Endpoints

properties

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

Customize Health Endpoint Details

properties

management.endpoint.health.show-details=always

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3. Key Actuator Endpoints

Endpoint	Description
/actuator	Lists all available endpoints
/actuator/health	Shows the application’s health status
/actuator/info	Displays custom application information
/actuator/metrics	Provides various performance metrics
/actuator/env	Shows environment properties
/actuator/loggers	Allows dynamic logger level changes
/actuator/mappings	Lists all request mappings
/actuator/threaddump	Shows thread dump for debugging
/actuator/prometheus	Exposes metrics in Prometheus format

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4. Customizing Actuator

Custom Health Indicator

You can define a custom health indicator by implementing the HealthIndicator interface.

java

import org.springframework.boot.actuate.health.Health;

import org.springframework.boot.actuate.health.HealthIndicator;

import org.springframework.stereotype.Component;

@Component

public class MyHealthIndicator implements HealthIndicator {

    @Override

    public Health health() {

        boolean isServiceUp = checkServiceHealth();

        if (isServiceUp) {

            return Health.up().withDetail(“service”, “Running Smoothly”).build();

        }

        return Health.down().withDetail(“service”, “Service Down!”).build();

    }

    private boolean checkServiceHealth() {

        return true; // Replace with real health check logic

    }

}

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5. Securing Actuator Endpoints

By default, Actuator endpoints are accessible without authentication. You can secure them using Spring Security.

Basic Authentication for Actuator Endpoints

Add the following Spring Security dependency:

xml

<dependency>

    <groupId>org.springframework.boot</groupId>

    <artifactId>spring-boot-starter-security</artifactId>

</dependency>

Then, configure security in application.properties:

properties

management.endpoints.web.exposure.include=*

management.endpoint.health.show-details=always

spring.security.user.name=admin

spring.security.user.password=admin123

This will require authentication when accessing endpoints.

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6. Monitoring with Prometheus and Grafana

To integrate Actuator with Prometheus, add:

properties

management.metrics.export.prometheus.enabled=true

management.endpoints.web.exposure.include=prometheus

Prometheus will scrape data from /actuator/prometheus, and you can visualize it in Grafana.