Introduction

As a developer, you’ve probably faced the daunting task of monitoring and managing your application’s performance. It’s like trying to find a needle in a haystack – you need to navigate through a sea of data to identify issues before they become major problems. However, with Spring Actuator a.ka Spring Boot Actuator, you can transform this arduous process into a streamlined, automated experience.

In this article, we’ll delve into the world of Spring Actuator and explore how it can revolutionize your app’s health monitoring. We’ll discuss its key features, and spring actuator endpoints, provide examples, and even include some code snippets to get you started.

What is Spring Actuator?

Spring Actuator is a feature of the Spring Boot framework that provides production-ready features for developers to monitor and manage their applications. It’s essentially a “dashboard” for your Spring Boot application, providing insights into its behavior and performance. To learn more about Spring Boot, Please refer to my Spring Boot article.

Key Features :

• Metrics: Collects and displays metrics such as CPU usage, memory usage, and request metrics.
• Health Check: Provides a health check endpoint that returns a status indicating whether the application is healthy or not.
• Beans: Lists all Spring beans in your application, making it easier to identify issues with specific components.
• Environment: Displays the current environment settings for your application, including configuration properties and profiles.
• Dump: Generates a dump of your application’s memory, which can be useful for debugging purposes.

How Spring Actuator Can Improve Your App’s Health Monitoring:

• Automated monitoring: With Spring Boot Actuator, you can automate the process of monitoring your application’s performance, freeing up time to focus on more pressing issues.
• Easy identification of problems: The spring actuator metrics and health check features allow you to quickly identify potential issues before they become major problems.
• Improved debugging: The beans and dump features make it easier to debug your application by providing detailed information about its internal state.

Example Use Case:

Let’s say you’re building a web application that serves as an e-commerce platform. With Spring Actuator, you can:

• Monitor CPU usage and memory consumption to ensure your app is running smoothly using Spring Actuator metrics features.
• Set up health checks to alert you when issues arise, such as database connection problems or authentication failures using Spring Actuator health features.
• Use the Beans feature to quickly identify which components are causing issues with your application.

How to enable Spring Actuator

To get started with Spring Actuator, simply include the following dependency in your `pom.xml` file (if you’re using Maven):

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

Once you’ve included this dependency, you can access Spring Actuator’s features by visiting your web browser’s `/actuator` endpoint. If you are new to Maven, Please read my detailed article on Maven.

What are Spring Actuator Endpoints?

Spring Actuator endpoints are URIs (Uniform Resource Identifiers) that expose various aspects of your Spring Boot application’s performance, configuration, and internal state. These endpoints provide a convenient way to monitor and manage your app without requiring extensive coding or debugging expertise.

Types of Spring Actuator Endpoints:

• Metrics: Exposes metrics about your application’s CPU usage, memory consumption, and request statistics.
• Health Check: Provides a health check endpoint that returns a status indicating whether the application is healthy or not.
• Beans: Lists all Spring beans in your application, making it easier to identify issues with specific components.
• Environment: Displays the current environment settings for your application, including configuration properties and profiles.
• Dump: Generates a dump of your application’s memory, which can be useful for debugging purposes.

Spring Actuator Endpoints

Spring Actuator provides several built-in endpoints that can be used to monitor and interact with an application. Below are the most used Spring Actuator Endpoints :

Security Endpoints

• ‘/actuator/auditevents`: Returns a stream of security audit events
• `/actuator/login-logout`: Provides information about recent login and logout activity

Metrics Endpoints

• `/actuator/metrics`: Returns a list of available metrics (e.g., CPU usage, memory usage)
• `/actuator/metric/{metricName}`: Returns the value of a specific metric (e.g., `cpu.usage`)
• `/actuator/counter/{counterName}`: Returns the count of a specific event

Health Endpoints

• `/actuator/health`: Returns the overall health status of the application
• `/actuator/health/detailed`: Returns detailed health information, including any failures

Info Endpoints

• `/actuator/info`: Returns general information about the application (e.g., version, build time)
• `/actuator/info/{infoType}`: Returns specific information about the application (e.g., `git`, `gitsha1`)

Dump Endpoints

• `/actuator/dump`: Returns a snapshot of the current thread dump
• `/actuator/mappedresources`: Returns a list of mapped resources

Beans Endpoints

• `/actuator/beans`: Returns a list of all Spring Beans in the application
• `/actuator/beans/{beanName}`: Returns detailed information about a specific bean (e.g., `configuration`, `dependencies`)

Log Endpoints

• `/actuator/logs`: Returns a stream of log messages for the application
• `/actuator/loggers`: Returns a list of configured loggers

Session Endpoints

• `/actuator/sessions/{sessionId}`: Returns information about a specific session (e.g., `attributes`, `maxInactiveInterval`)
• `/actuator/sessions`: Returns a stream of recent sessions

Jolokia and Remote Shell Endpoints

• `/actuator/jolokia`: Exposes a JMX-over-HTTP interface for monitoring the application
• `/actuator/remote-shell`: Enables remote shell access to the application ( Note: This endpoint should be used with caution, as it allows arbitrary code execution)

Other Endpoints

• `/actuator/flyway` : Returns information about database migrations (e.g., `applied`, `failed`)
• `/actuator/capabilities` : Returns a list of supported capabilities (e.g., `jolokia`, `web`)
• `/actuator/data-redis`: Exposes Redis data and statistics

Keep in mind that not all endpoints are enabled by default. Some may need to be explicitly configured or exposed through a `management.endpoints.web.exposure.include` property.

Example Use Case: Monitoring CPU Usage

Suppose you’re building an e-commerce platform that handles a high volume of requests. To ensure optimal performance, you want to monitor your app’s CPU usage. With Spring Actuator Metrics, you can expose the `/actuator/metrics/cpu` endpoint to view real-time CPU usage statistics.

GET http://localhost:8080/actuator/metrics/cpu

The response will contain a JSON object with metrics about CPU usage, including:

• `cpuUsagePercentage`
• `maxAccumulated_cpu_usage`
• `average_accumulated_cpu_usage`

Example Use Case: Health Check

To ensure your application is running smoothly, you can set up a Spring Actuator Health check endpoint using Spring Actuator. Suppose you have a database connection that needs to be verified periodically.

GET http://localhost:8080/actuator/health

The response will contain a JSON object with the current health status of your application:

• `status`: Indicates whether the application is healthy or not.
• `diskSpace`: Displays available disk space.
• `memory`: Shows memory usage statistics.

Security Considerations

When exposing actuator endpoints, keep in mind that they can be accessed by anyone. To mitigate this risk, you can secure your endpoints using HTTP

Basic Authentication or another authentication mechanism. Add this below bean to your configuration class

@Bean
public SecurityWebFilterChain securityWebFilterChain(ServerHttpSecurity http) {
  http.authorizeExchange()
      .atPath("/actuator/metrics/cpu")
      .authenticated();
  return http.build();
}

Conclusion:

Spring Actuator is a powerful tool that can revolutionize your app’s health monitoring. By automating the process of monitoring and providing easy-to-use features for debugging and identification of problems, it frees up time for more pressing issues. With its simple setup and access to key metrics, health checks, beans, environment settings, and dump features, you can take your application’s performance to the next level.

FAQ

Q: What is the main purpose of Spring Actuator?

A: Consider the Spring Actuator as a Swiss Army knife for your application. It’s a collection of endpoints that help you monitor and interact with your app, making it easier to identify issues and troubleshoot problems.

Q: I’ve heard that Actuator is like a security hole in my app. Is that true?

A: Absolutely not! While it’s true that Spring Actuator provides some security-related features (like auditing and login/logout tracking), the majority of its functionality is focused on monitoring, debugging, and performance optimization. Don’t worry – your app will still be secure!

Q: How do I use Actuator to troubleshoot issues in my app?

A: It’s super easy! Just point your web browser or a tool like cURL at one of the many Spring Actuator endpoints (e.g., `/actuator/health`, `/actuator/metrics`, etc.). This will give you instant insight into what’s going on with your application. You can also use tools like Spring Boot Dashboard to simplify the process.

Q: Can I use Spring Actuator in production?

A: Absolutely! In fact, many production-ready applications rely heavily on Spring Actuator for monitoring and performance optimization. Just remember to configure Actuator to expose only the endpoints you need (using `management.endpoints.web.exposure.include`, for example), and make sure your app is secured behind a firewall or load balancer.

Q: How do I get started with Spring Actuator?

A: Easy peasy! Just add the necessary dependencies to your project (`spring-boot-starter-actuator`), and you’ll be good to go. Then, simply navigate to one of the Spring Actuator endpoints in a web browser or tool like cURL to see what’s available. You can also consult the Spring Boot documentation for more detailed guidance and configuration options.