Actuator监控

什么是 Actuator

Spring Boot Actuator 提供了生产级别的监控和管理功能，包括健康检查、指标收集、审计、HTTP 追踪等。

快速开始

添加依赖

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

配置端点

# application.yml
management:
  endpoints:
    web:
      exposure:
        include: "*"  # 暴露所有端点
      base-path: /actuator  # 端点基础路径
  endpoint:
    health:
      show-details: always  # 显示健康检查详情

访问端点

# 健康检查
curl http://localhost:8080/actuator/health

# 所有端点
curl http://localhost:8080/actuator

常用端点

端点	说明	默认启用
/health	健康检查	是
/info	应用信息	是
/metrics	指标数据	是
/env	环境配置	否
/beans	所有 Bean	否
/mappings	请求映射	否
/loggers	日志配置	否
/threaddump	线程转储	否
/heapdump	堆转储	否
/shutdown	关闭应用	否

健康检查

基本健康检查

curl http://localhost:8080/actuator/health

{
  "status": "UP",
  "components": {
    "db": {
      "status": "UP",
      "details": {
        "database": "MySQL",
        "validationQuery": "isValid()"
      }
    },
    "diskSpace": {
      "status": "UP",
      "details": {
        "total": 499963174912,
        "free": 123456789012,
        "threshold": 10485760
      }
    },
    "redis": {
      "status": "UP",
      "details": {
        "version": "6.2.6"
      }
    }
  }
}

自定义健康检查

@Component
public class CustomHealthIndicator implements HealthIndicator {
    
    @Override
    public Health health() {
        // 检查外部服务
        boolean serviceUp = checkExternalService();
        
        if (serviceUp) {
            return Health.up()
                .withDetail("service", "External Service")
                .withDetail("status", "Available")
                .build();
        } else {
            return Health.down()
                .withDetail("service", "External Service")
                .withDetail("error", "Service unavailable")
                .build();
        }
    }
    
    private boolean checkExternalService() {
        // 实现检查逻辑
        return true;
    }
}

健康检查分组

management:
  endpoint:
    health:
      group:
        liveness:
          include: livenessState
        readiness:
          include: readinessState,db,redis

# Kubernetes 探针
curl http://localhost:8080/actuator/health/liveness
curl http://localhost:8080/actuator/health/readiness

指标监控

查看指标

# 所有指标
curl http://localhost:8080/actuator/metrics

# 特定指标
curl http://localhost:8080/actuator/metrics/jvm.memory.used
curl http://localhost:8080/actuator/metrics/http.server.requests

{
  "name": "jvm.memory.used",
  "description": "The amount of used memory",
  "baseUnit": "bytes",
  "measurements": [
    {
      "statistic": "VALUE",
      "value": 268435456
    }
  ],
  "availableTags": [
    {
      "tag": "area",
      "values": ["heap", "nonheap"]
    }
  ]
}

常用指标

指标	说明
jvm.memory.used	JVM 内存使用
jvm.memory.max	JVM 最大内存
jvm.gc.pause	GC 暂停时间
jvm.threads.live	活跃线程数
http.server.requests	HTTP 请求统计
system.cpu.usage	CPU 使用率
process.uptime	进程运行时间

自定义指标

@Component
public class OrderMetrics {
    
    private final Counter orderCounter;
    private final Timer orderTimer;
    
    public OrderMetrics(MeterRegistry registry) {
        this.orderCounter = Counter.builder("orders.created")
            .description("Number of orders created")
            .tag("type", "online")
            .register(registry);
            
        this.orderTimer = Timer.builder("orders.process.time")
            .description("Order processing time")
            .register(registry);
    }
    
    public void recordOrder() {
        orderCounter.increment();
    }
    
    public void recordProcessTime(Runnable task) {
        orderTimer.record(task);
    }
}

集成 Prometheus

添加依赖

<dependency>
    <groupId>io.micrometer</groupId>
    <artifactId>micrometer-registry-prometheus</artifactId>
</dependency>

配置

management:
  endpoints:
    web:
      exposure:
        include: prometheus,health,info,metrics
  metrics:
    export:
      prometheus:
        enabled: true
    tags:
      application: ${spring.application.name}

访问 Prometheus 端点

curl http://localhost:8080/actuator/prometheus

# HELP jvm_memory_used_bytes The amount of used memory
# TYPE jvm_memory_used_bytes gauge
jvm_memory_used_bytes{area="heap",id="G1 Eden Space",} 1.048576E7
jvm_memory_used_bytes{area="heap",id="G1 Old Gen",} 2.097152E7
jvm_memory_used_bytes{area="heap",id="G1 Survivor Space",} 1048576.0

# HELP http_server_requests_seconds
# TYPE http_server_requests_seconds summary
http_server_requests_seconds_count{method="GET",status="200",uri="/api/users",} 100.0
http_server_requests_seconds_sum{method="GET",status="200",uri="/api/users",} 5.5

端点安全

配置安全访问

@Configuration
@EnableWebSecurity
public class ActuatorSecurityConfig {
    
    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        http
            .authorizeHttpRequests(auth -> auth
                .requestMatchers("/actuator/health").permitAll()
                .requestMatchers("/actuator/**").hasRole("ADMIN")
                .anyRequest().authenticated()
            )
            .httpBasic(Customizer.withDefaults());
        return http.build();
    }
}

配置用户

spring:
  security:
    user:
      name: admin
      password: admin123
      roles: ADMIN

自定义端点

@Component
@Endpoint(id = "custom")
public class CustomEndpoint {
    
    @ReadOperation
    public Map<String, Object> info() {
        Map<String, Object> info = new HashMap<>();
        info.put("name", "Custom Endpoint");
        info.put("version", "1.0.0");
        info.put("timestamp", System.currentTimeMillis());
        return info;
    }
    
    @WriteOperation
    public void update(@Selector String name, String value) {
        // 更新操作
    }
    
    @DeleteOperation
    public void delete(@Selector String name) {
        // 删除操作
    }
}

# 访问自定义端点
curl http://localhost:8080/actuator/custom

小结

Spring Boot Actuator 提供了丰富的监控和管理功能，包括健康检查、指标监控、环境配置等。结合 Prometheus 和 Grafana 可以构建完整的监控体系。

面试题预览

常见面试题

1. Spring Boot Actuator 提供了哪些端点？
2. 如何自定义健康检查？
3. 如何将 Actuator 指标暴露给 Prometheus？