management:
  endpoints:
    web:
      exposure:
        include: health,info,metrics,prometheus

curl http://localhost:8080/actuator/health
# {"status":"UP","components":{"db":{"status":"UP"},"diskSpace":{"status":"UP"}}}

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

// 実行成功

management:
  endpoints:
    web:
      exposure:
        include: health,info,metrics,env,loggers
      base-path: /actuator
  endpoint:
    health:
      show-details: when-authorized
    metrics:
      enabled: true
  info:
    env:
      enabled: true

設定が反映されました。

@Component
public class PaymentGatewayHealthIndicator implements HealthIndicator {

    private final RestTemplate restTemplate;

    public PaymentGatewayHealthIndicator(RestTemplate restTemplate) {
        this.restTemplate = restTemplate;
    }

    @Override
    public Health health() {
        try {
            ResponseEntity<String> response = restTemplate.getForEntity(
                "https://api.payment-gateway.com/ping", String.class);
            if (response.getStatusCode().is2xxSuccessful()) {
                return Health.up()
                    .withDetail("gateway", "reachable")
                    .withDetail("responseTime", response.getHeaders().getDate())
                    .build();
            }
            return Health.down()
                .withDetail("gateway", "unhealthy")
                .withDetail("statusCode", response.getStatusCode())
                .build();
        } catch (Exception e) {
            return Health.down()
                .withDetail("gateway", "unreachable")
                .withDetail("error", e.getMessage())
                .build();
        }
    }
}

// 実行成功

{
  "status": "DOWN",
  "components": {
    "diskSpace": {"status": "UP", "details": {"total": 536870912000, "free": 268435456000}},
    "db": {"status": "UP", "details": {"database": "MySQL", "validationQuery": "SELECT 1"}},
    "paymentGateway": {"status": "DOWN", "details": {"gateway": "unreachable", "error": "Connection refused"}}
  }
}

# 利用可能なすべてのメトリクスを一覧表示
curl http://localhost:8080/actuator/metrics

# 特定のメトリクスを取得:HTTPサーバーリクエスト
curl http://localhost:8080/actuator/metrics/http.server.requests

# フィルタリングしたメトリクスを取得
curl "http://localhost:8080/actuator/metrics/http.server.requests?tag=uri:/api/v1/orders&tag=status:200"

{"status":"ok","data":{}}

@Service
public class OrderMetrics {

    private final Counter orderCreatedCounter;
    private final Timer orderCreationTimer;
    private final AtomicLong pendingOrders;

    public OrderMetrics(MeterRegistry registry) {
        this.orderCreatedCounter = Counter.builder("orderflow.orders.created")
            .description("Total orders created")
            .tag("service", "orderflow")
            .register(registry);

        this.orderCreationTimer = Timer.builder("orderflow.orders.creation.time")
            .description("Order creation time")
            .register(registry);

        this.pendingOrders = registry.gauge("orderflow.orders.pending",
            new AtomicLong(0));
    }

    public void recordOrderCreated() {
        orderCreatedCounter.increment();
        pendingOrders.incrementAndGet();
    }

    public void recordOrderCompleted() {
        pendingOrders.decrementAndGet();
    }

    public Timer getCreationTimer() {
        return orderCreationTimer;
    }
}

// 実行成功

@Endpoint(id = "orderstats")
@Component
public class OrderStatsEndpoint {

    private final OrderRepository orderRepository;

    public OrderStatsEndpoint(OrderRepository orderRepository) {
        this.orderRepository = orderRepository;
    }

    @ReadOperation
    public Map<String, Object> orderStats() {
        long total = orderRepository.count();
        long pending = orderRepository.countByStatus("PENDING");
        long completed = orderRepository.countByStatus("COMPLETED");
        long cancelled = orderRepository.countByStatus("CANCELLED");
        return Map.of(
            "totalOrders", total,
            "pendingOrders", pending,
            "completedOrders", completed,
            "cancelledOrders", cancelled,
            "completionRate", total > 0
                ? String.format("%.2f%%", (double) completed / total * 100)
                : "N/A"
        );
    }

    @ReadOperation
    public Map<String, Object> orderStatsByStatus(
            @Selector String status) {
        long count = orderRepository.countByStatus(status.toUpperCase());
        return Map.of("status", status, "count", count);
    }
}

// 実行成功

management:
  endpoint:
    orderstats:
      enabled: true
  endpoints:
    web:
      exposure:
        include: health,info,orderstats

curl http://localhost:8080/actuator/orderstats
# {"totalOrders":1523,"pendingOrders":45,"completedOrders":1420,"cancelledOrders":58,"completionRate":"93.30%"}

curl http://localhost:8080/actuator/orderstats/PENDING
# {"status":"PENDING","count":45}

# application-prod.yml
management:
  server:
    port: 8081                    # 管理ポートの分離
    address: 127.0.0.1            # localhostのみにバインド
  endpoints:
    web:
      exposure:
        include: health,prometheus,orderstats
      base-path: /actuator
  endpoint:
    health:
      show-details: when-authorized
    env:
      enabled: false
    beans:
      enabled: false
    heapdump:
      enabled: false

監視設定が読み込まれました
Prometheusターゲット:3件アクティブ
Grafanaダッシュボード:準備完了

# application.yml
management:
  endpoints:
    web:
      exposure:
        include: health,info,metrics,prometheus,orderstats
  endpoint:
    health:
      show-details: when-authorized
    orderstats:
      enabled: true
  metrics:
    tags:
      application: ${spring.application.name}
  info:
    env:
      enabled: true

info:
  app:
    name: OrderFlow Service
    version: @project.version@
    description: Eコマース注文管理マイクロサービス

// PaymentGatewayHealthIndicator.java
@Component
public class PaymentGatewayHealthIndicator implements HealthIndicator {
    private final RestTemplate restTemplate;
    public PaymentGatewayHealthIndicator(RestTemplate restTemplate) {
        this.restTemplate = restTemplate;
    }
    @Override
    public Health health() {
        try {
            ResponseEntity<String> resp = restTemplate
                .getForEntity("https://api.payment.com/ping", String.class);
            return resp.getStatusCode().is2xxSuccessful()
                ? Health.up().withDetail("gateway", "reachable").build()
                : Health.down().withDetail("statusCode", resp.getStatusCode()).build();
        } catch (Exception e) {
            return Health.down().withDetail("error", e.getMessage()).build();
        }
    }
}

// OrderStatsEndpoint.java
@Endpoint(id = "orderstats")
@Component
public class OrderStatsEndpoint {
    private final OrderRepository orderRepository;
    public OrderStatsEndpoint(OrderRepository orderRepository) {
        this.orderRepository = orderRepository;
    }
    @ReadOperation
    public Map<String, Object> stats() {
        return Map.of(
            "total", orderRepository.count(),
            "pending", orderRepository.countByStatus("PENDING"),
            "completed", orderRepository.countByStatus("COMPLETED")
        );
    }
}