高可用事件管理API的架构设计与工程实践

// 事件对象设计示例
public class SystemEvent {
    private final String eventId;  // 事件ID使用UUID确保唯一性
    private final EventType type; // 枚举类型：INCIDENT/ALERT/RESOLUTION
    private final Instant createdAt; // 精确到纳秒的时间戳
    private final Map<String, Object> payload; // 使用不可变集合
    
    // 构造函数设为private确保不可变
    private SystemEvent(String eventId, EventType type, Map<String, Object> payload) {
        this.eventId = UUID.randomUUID().toString();
        this.type = type;
        this.createdAt = Instant.now();
        this.payload = Collections.unmodifiableMap(new HashMap<>(payload));
    }
}

// 使用Flink实现事件处理拓扑
public class EventProcessingTopology {
    public static void main(String[] args) {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        
        // 从Kafka读取事件流
        DataStream<SystemEvent> events = env
            .addSource(new FlinkKafkaConsumer<>("events", new EventDeserializer(), properties))
            .name("kafka-source");
        
        // 事件分类处理
        events.keyBy(Event::getType)
            .process(new EventProcessor())
            .name("event-processor")
            .addSink(new ElasticsearchSink<>())
            .name("es-sink");
        
        // 关键指标监控流
        events.process(new MetricCollector())
            .name("metric-collector")
            .addSink(new PrometheusSink())
            .name("metrics-sink");
    }
}

// 事件处理算子
class EventProcessor extends KeyedProcessFunction<EventType, SystemEvent, ProcessedEvent> {
    @Override
    public void processElement(SystemEvent event, Context ctx, Collector<ProcessedEvent> out) {
        // 状态检查
        ValueState<Boolean> processedFlag = getRuntimeContext()
            .getState(new ValueStateDescriptor<>("processedFlag", Boolean.class));
        
        if (processedFlag.value() == null) {
            // 执行核心业务逻辑
            ProcessedEvent result = BusinessLogic.execute(event);
            
            // 更新状态并输出
            processedFlag.update(true);
            out.collect(result);
        }
    }
}

// 使用Resilience4j实现熔断
CircuitBreakerConfig config = CircuitBreakerConfig.custom()
    .failureRateThreshold(50) // 失败率阈值
    .waitDurationInOpenState(Duration.ofSeconds(60)) // 熔断时间
    .ringBufferSizeInHalfOpenState(10) // 半开状态请求数
    .ringBufferSizeInClosedState(100) // 关闭状态请求数
    .build();

CircuitBreaker circuitBreaker = CircuitBreaker.of("eventService", config);

Supplier<EventResponse> decoratedSupplier = CircuitBreaker
    .decorateSupplier(circuitBreaker, () -> eventService.queryEvents());

// 降级处理
Try<EventResponse> result = Try.ofSupplier(decoratedSupplier)
    .recover(throwable -> { 
        // 返回缓存中的历史数据
        return cacheService.getHistoricalEvents(); 
    });