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Adding Actuator to Your Application

You are planning to develop a new RESTful API to complement your football-related suite of services and want to ensure your application is responsive and resilient. To effectively monitor your application’s health, you’ll be utilizing Spring Boot Actuator.

What is Spring Boot Actuator?

Spring Boot Actuator provides a set of production-ready functionalities packaged with the Spring Framework. It includes various built-in tools and endpoints designed to monitor, manage, and interact with Spring Boot applications in production environments. The Actuator simplifies understanding and addressing runtime behaviors in Spring Boot applications by exposing multiple endpoints, including health, metrics, info, dump, and env.

Once the Actuator dependency is included in your application, you’ll have access to numerous out-of-the-box endpoints, which can be customized or extended according to your needs.

Getting Started

In this section, we’ll create an application using the Spring Initializr tool. You can access this tool either through your browser at https://start.spring.io or by integrating it into your favorite code editor.

Steps to Include Actuator

Follow these steps to create a project with Actuator enabled and explore the provided endpoints:

  1. Create a New Project:

    • Open Spring Initializr.

    • Use the same parameters as in the Creating a RESTful API recipe from Chapter 1, changing the following options:

      • Artifact: footballobs

      • Dependencies: Select Spring Web and Spring Boot Actuator.

  2. Download and Unzip the Project:

    • Download the generated template and unzip it into your working directory.

  3. Configure Actuator Endpoints:

    • Before running your application, create an application.yml file in the src/main/resources folder and add the following configuration:

management:
  endpoints:
    web:
      exposure:
        include: health, env, metrics, beans, loggers

  1. Run Your Application:

    • Start your application. You can now access the exposed Actuator endpoints:

      • Health Endpoint: http://localhost:8080/actuator/health – Provides health information about your application.

      • Environment Endpoint: http://localhost:8080/actuator/env – Returns the environment variables of the application.

      • Metrics Endpoint: http://localhost:8080/actuator/metrics – Lists the metrics exposed by the application. For specific metrics, append the metric name (e.g., http://localhost:8080/actuator/metrics/process.cpu.usage).

      • Beans Endpoint: http://localhost:8080/actuator/beans – Lists the beans registered in the IoC container.

      • Loggers Endpoint: http://localhost:8080/actuator/loggers – Displays log levels and loggers of the application and allows runtime modification of log levels.

  2. Explore Additional Endpoints:

    • You have only exposed a subset of the available endpoints. For a complete list, refer to the official documentation: Spring Boot Actuator Endpoints.

How It Works

Integrating Actuator into your application provides a variety of endpoints for monitoring and managing application behavior. By default, all endpoints except the shutdown endpoint are enabled. The shutdown endpoint allows for graceful application termination. You can expose endpoints via HTTP requests or JMX, with HTTP being preferred for standard monitoring tools.

Additional components, such as Spring Data JPA, may expose more metrics that require configuration for monitoring purposes.

Security Considerations

Some Actuator endpoints may expose sensitive information. By default, only the health endpoint is exposed. Depending on your application’s accessibility, you may want to secure other endpoints. You can implement security configurations, as demonstrated below:

@Configuration
public class SecurityConfig {
    @Bean
    public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
        return http
            .authorizeHttpRequests(authorize ->
                authorize.requestMatchers("/actuator/**")
                    .hasRole("ADMIN")
                    .anyRequest().authenticated())
            .oauth2ResourceServer(oauth2 -> oauth2.jwt(Customizer.withDefaults()))
            .build();
    }
}

For more details on securing Actuator endpoints, refer to the official documentation: Securing Actuator Endpoints.