Spring Boot Actuator: Custom Info Endpoint

This snippet illustrates how to add custom information to the /info endpoint in Spring Boot Actuator. This is useful for displaying application-specific details such as build version, environment details, or any other relevant information that can aid in debugging or monitoring.

Add Custom InfoContributor

Here, a `CustomInfoContributor` is created, implementing the `InfoContributor` interface. The `contribute` method builds a map containing custom information about the application, such as the application name, version, and environment. The `withDetail` method then adds this map to the info endpoint's response.

import org.springframework.boot.actuate.info.Info;
import org.springframework.boot.actuate.info.InfoContributor;
import org.springframework.stereotype.Component;

import java.util.HashMap;
import java.util.Map;

@Component
public class CustomInfoContributor implements InfoContributor {

    @Override
    public void contribute(Info.Builder builder) {
        Map<String, Object> details = new HashMap<>();
        details.put("app-name", "My Awesome Application");
        details.put("version", "1.0.0");
        details.put("environment", System.getenv("ENVIRONMENT"));

        builder.withDetail("custom-info", details);
    }
}

Configuration (application.properties/yml)

Ensure that the `info` endpoint is exposed. Add `management.endpoints.web.exposure.include=info` to your `application.properties` or `application.yml` file. This makes the `/actuator/info` endpoint accessible.

#application.properties
management.endpoints.web.exposure.include=info

Accessing the Info Endpoint

Accessing the `info` endpoint via a GET request to `http://localhost:8080/actuator/info` will now include the custom information provided by the `CustomInfoContributor`.

curl http://localhost:8080/actuator/info

Concepts Behind the Snippet

Spring Boot Actuator's /info endpoint is designed to expose general information about the application. Using InfoContributor allows you to extend this endpoint with custom details.

Real-Life Use Case Section

In a microservices architecture, the /info endpoint can be used to display which version of the microservice is running. This is crucial during deployments and for debugging issues across multiple services. It helps operators and developers quickly identify the specific version and environment of each service.

Best Practices

• Avoid exposing sensitive information in the /info endpoint.
• Use environment variables or configuration files to manage the information contributed to the /info endpoint.
• Keep the information relevant and concise.

Interview Tip

Be prepared to discuss how you can use the /info endpoint to expose application-specific information and how it helps in managing and monitoring the application. Explain how InfoContributor helps add custom details and what kind of information is relevant.

When to use them

Use the custom /info endpoint when you need to display application-specific details that are not readily available through other Actuator endpoints. This could include build information, environment details, or any other relevant metadata.

Memory Footprint

The memory footprint is minimal, primarily related to the storage of the custom information added via the InfoContributor. Ensure the custom information added is not excessively large or complex to avoid unnecessary memory consumption.

Alternatives

Instead of using the Actuator /info endpoint, you could expose a custom endpoint that returns the same information. However, using Actuator provides a standardized way to manage and monitor the application.

Pros

• Provides a standardized way to expose application-specific information.
• Integrates seamlessly with Spring Boot Actuator.
• Easy to implement and configure.

Cons

• Can expose sensitive information if not properly secured.
• Requires careful planning to ensure the information is relevant and concise.