聊聊lettuce的指标监控-优快云博客

本文探讨了Lettuce的指标监控机制，重点关注DefaultCommandLatencyEventPublisher如何根据EventPublisherOptions的配置发布命令延迟事件。通过LettuceConnectionConfiguration创建的DefaultClientResources和DefaultEventPublisherOptions，默认设置了10分钟的事件发送间隔。CommandLatencyCollector负责收集延迟数据，而CommandHandler在处理命令时记录延时。此外，展示了如何订阅和消费事件来获取Lettuce的监控指标，利用事件驱动架构实现灵活的指标监控。

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序

本文主要研究一下lettuce的指标监控

DefaultCommandLatencyEventPublisher

lettuce-core-5.0.4.RELEASE-sources.jar!/io/lettuce/core/event/metrics/DefaultCommandLatencyEventPublisher.java

public class DefaultCommandLatencyEventPublisher implements MetricEventPublisher {

    private final EventExecutorGroup eventExecutorGroup;
    private final EventPublisherOptions options;
    private final EventBus eventBus;
    private final CommandLatencyCollector commandLatencyCollector;

    private final Runnable EMITTER = this::emitMetricsEvent;

    private volatile ScheduledFuture<?> scheduledFuture;

    public DefaultCommandLatencyEventPublisher(EventExecutorGroup eventExecutorGroup, EventPublisherOptions options,
            EventBus eventBus, CommandLatencyCollector commandLatencyCollector) {

        this.eventExecutorGroup = eventExecutorGroup;
        this.options = options;
        this.eventBus = eventBus;
        this.commandLatencyCollector = commandLatencyCollector;

        if (!options.eventEmitInterval().isZero()) {
            scheduledFuture = this.eventExecutorGroup.scheduleAtFixedRate(EMITTER, options.eventEmitInterval().toMillis(),
                    options.eventEmitInterval().toMillis(), TimeUnit.MILLISECONDS);
        }
    }

    @Override
    public boolean isEnabled() {
        return !options.eventEmitInterval().isZero() && scheduledFuture != null;
    }

    @Override
    public void shutdown() {

        if (scheduledFuture != null) {
            scheduledFuture.cancel(true);
            scheduledFuture = null;
        }
    }

    @Override
    public void emitMetricsEvent() {

        if (!isEnabled() || !commandLatencyCollector.isEnabled()) {
            return;
        }

        eventBus.publish(new CommandLatencyEvent(commandLatencyCollector.retrieveMetrics()));
    }

}

这里判断如果EventPublisherOptions的eventEmitInterval不为0的话，则开启调度定时调用emitMetricsEvent发布命令延时事件

LettuceConnectionConfiguration

spring-boot-autoconfigure-2.0.4.RELEASE-sources.jar!/org/springframework/boot/aut