Beginner's guide to Springboot - Actuator

Spring boot actuator explained in detailed with coding example helpful for beginner for springboot

1. Springboot - Actuator

2. Introduction to Spring Boot Actuator Introduction: Spring Boot Actuator is a subproject that enhances the manageability and observability of Spring Boot applications. It offers built-in features for monitoring, management, and diagnostics. Key Objectives: Provide real-time insights into application health. Enable efficient metrics collection and analysis. Facilitate application management and configuration retrieval

3. Why Use Spring Boot Actuator? Real-time Insights: Actuator enables you to gain real-time insights into the health and behavior of your application. Metrics Collection: It allows for the collection of various application metrics, aiding in performance analysis. Application Management: Actuator provides endpoints for tasks like shutdown and configuration retrieval, simplifying application management.

4. Actuator Endpoints Endpoint Overview: Spring Boot Actuator exposes a set of predefined endpoints, each serving a specific purpose. Common Endpoints: Has essential endpoints such as ‘ / health’ ‘ / metrics’ ‘ / info’ and ‘ / env ’ Additional custom endpoints can also be created.

5. Health Endpoint /health Endpoint: The / health endpoint reports the application's overall health status. It performs checks on various components (e.g., database, external services) and returns a status (UP or DOWN ). Use Case : Actuator's /health endpoint is invaluable for monitoring the health of your application. How It Works : The /health endpoint performs a series of checks on various components, such as databases, messaging queues, and external services. It returns a simple status: "UP" if all checks pass, and "DOWN" if any check fails. Benefits : Monitoring health helps ensure the application is running smoothly. Load balancers and orchestrators use this endpoint to determine whether an instance is healthy and should receive traffic. Example : Operations teams can set up automated monitoring tools to periodically check the health status of all application instances and receive alerts if any instance becomes unhealthy.

6. Metrics Endpoint / metrics endpoint The / metrics endpoint collects and exposes a wide range of application metrics. Metrics can include JVM statistics, memory usage, request/response counts, and custom metrics. Use Case : Actuator's /metrics endpoint allows you to collect and expose various application metrics. How It Works : Spring Boot captures metrics related to memory usage, garbage collection, HTTP request/response statistics, and more. Custom metrics can also be added. Benefits : Tracking performance metrics helps you identify bottlenecks, memory leaks, and performance issues. It aids in optimizing your application for efficiency. Example : DevOps teams can use Actuator's metrics to visualize trends over time and proactively address performance degradation.

7. Info Endpoint / info endpoint: The / info endpoint provides custom metadata about the application. This is a great place to display version information, build details, or any other relevant data.

8. Environment Endpoint / env Endpoint: The / env e ndpoint displays information about application properties and environment variables. It aids in debugging and understanding the runtime environment. Use Case : Actuator's / configprops and / env endpoints provide insights into application properties and environment variables. How It Works : The / configprops endpoint lists all Spring @ ConfigurationProperties beans, which often correspond to application configuration. The / env endpoint shows environment-specific properties. Benefits : Retrieving configuration details simplifies debugging and troubleshooting. It allows you to verify that the application is using the correct settings in different environments. Example : Developers can use the / configprops endpoint to check if their custom configuration properties are correctly loaded and apply the expected values.

9. Shutdown Endpoint / shutdown endpoint: The / shutdown endpoint allows for a graceful shutdown of the application, but it requires proper security configurations to prevent misuse in production . Use Case : The /shutdown endpoint can be used for a graceful shutdown of the application. How It Works : You can configure Spring Security to secure the /shutdown endpoint, ensuring that only authorized users or scripts can initiate a shutdown. Benefits : In production environments, secure shutdowns are essential to prevent accidental or unauthorized termination of application instances. Example : Operations teams can use secure shutdown to gracefully stop an instance during maintenance or scaling down, ensuring no data loss or disruption.

10. Custom Endpoints Custom Endpoints : Spring Boot Actuator allows you to create custom endpoints tailored to your application's specific management needs. These endpoints can expose application-specific data or perform custom actions.

11. Configuration and Security Configuration : Configure Actuator endpoints in application.properties or application.yml Customize which endpoints are enabled, their properties, and security settings . In your application.properties or application.yml , you can enable or disable specific Actuator endpoints by using the management.endpoints.web.exposure.include property . This property controls which endpoints are accessible over HTTP . # Enable specific endpoints management.endpoints.web.exposure.include = health,info,metrics # Disable specific endpoints (by omitting them) # management.endpoints.web.exposure.include = health,info,metrics

12. Customize Endpoint Properties: Actuator endpoints often come with customizable properties that allow you to fine-tune their behavior. For example, you can set the response status of the / health endpoint to "UP" even if some checks fail . # Customize the health endpoint's status to "UP" even if checks fail management.endpoint.health.status.order =UP

13. Security Configuration Securing Actuator endpoints is crucial, especially in production environments where you want to restrict access to sensitive endpoints like /shutdown . You can use Spring Security or other authentication mechanisms to secure these endpoints.

14. import org.springframework.boot.actuate.autoconfigure.security.servlet.EndpointRequest; import org.springframework.context.annotation.Bean ; import org.springframework.context.annotation.Configuration ; import org.springframework.security.config.annotation.web.builders.HttpSecurity; import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity; import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter; @Configuration @ EnableWebSecurity public class SecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure( HttpSecurity http) throws Exception { http . authorizeRequests () . requestMatchers (EndpointRequest.to("shutdown")). hasRole ("ADMIN") // Secure the /shutdown endpoint . antMatchers ("/**"). permitAll () // Allow public access to other endpoints .and() . httpBasic (); // Use HTTP Basic Authentication } }

15. Enabling Actuator Enabling Actuator : Add the Actuator dependency to your project . <dependency> < groupId > org.springframework.boot </ groupId > < artifactId >spring-boot-starter-actuator</ artifactId > </dependency> Configure Actuator endpoints based on your application's requirements.

16. Code Example 1: Configuration Server ( application.properties ) # Configuration Server port server.port =8888 # Git repository URL where configuration files are stored spring.cloud.config.server.git.uri =https://github.com/yourusername/config-repo.git # Git repository search paths spring.cloud.config.server.git.search -paths= configs

17. Code Example 2: Configuration Client ( application.properties ) # Application name (used to fetch configuration from the server) spring.application.name=product-service # URI of the Configuration Server spring.cloud.config.uri =http://config-server-host:8888 # Active profile spring.profiles.active =development

18. Code Example 3: Configuration File in Git Repository (product-service- development.properties ) # Database configuration spring.datasource.url= jdbc:mysql ://localhost:3306/ productsdb spring.datasource.username = dbuser spring.datasource.password = dbpassword # Service-specific configuration product- service.max -allowed-quantity=10 product- service.api -key=your- api -key

19. Code Example 4: Fetching Configuration in Configuration Client (Java Code) import org.springframework.beans.factory.annotation.Value ; import org.springframework.context.annotation.Configuration ; @Configuration public class ProductServiceConfiguration { @Value("${spring.datasource.url}") private String databaseUrl ; @Value("${product- service.max -allowed-quantity}") private int maxAllowedQuantity ; @Value("${product- service.api -key}") private String apiKey ; // Getter methods public String getDatabaseUrl () { return databaseUrl ; } public int getMaxAllowedQuantity () { return maxAllowedQuantity ; } public String getApiKey () { return apiKey ; } }