What is Spring Boot Actuator and what are its key endpoints? Spring Boot Actuator क्या है और इसके key endpoints कौन से हैं?

Spring Boot Actuator provides built-in endpoints for monitoring and managing applications. Expose health, metrics, and environment information via HTTP or JMX. Essential for production applications to track performance and troubleshoot issues.

// Enable Actuator
// pom.xml
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

// application.yml
management:
  endpoints:
    web:
      exposure:
        include: health,metrics,info,env,loggers
  endpoint:
    health:
      show-details: always
    metrics:
      export:
        prometheus:
          enabled: true

// Custom Health Check
@Component
public class CustomHealthIndicator implements HealthIndicator {
    @Override
    public Health health() {
        try {
            // Check critical service
            checkDatabaseConnection();
            return Health.up()
                .withDetail('database', 'connected')
                .build();
        } catch (Exception e) {
            return Health.down()
                .withDetail('error', e.getMessage())
                .build();
        }
    }
    
    private void checkDatabaseConnection() {
        // Verify database is accessible
    }
}

// Custom Metrics
@Component
public class BusinessMetrics {
    private final MeterRegistry meterRegistry;
    
    public BusinessMetrics(MeterRegistry meterRegistry) {
        this.meterRegistry = meterRegistry;
    }
    
    public void recordOrderCreated() {
        meterRegistry.counter('orders.created').increment();
    }
    
    public void recordOrderValue(double value) {
        meterRegistry.timer('order.processing.time').record(
            value, TimeUnit.MILLISECONDS);
    }
}

// Access endpoints
// http://localhost:8080/actuator/health
// http://localhost:8080/actuator/metrics
// http://localhost:8080/actuator/metrics/http.server.requests