hystrix源码小贴士之Yammer Publisher

HystrixYammerMetricsPublisher

　　继承HystrixMetricsPublisher，创建HystrixYammerMetricsPublisherCommand、HystrixYammerMetricsPublisherThreadPool、HystrixYammerMetricsPublisherCollapser。

 @Override
    public HystrixMetricsPublisherCommand getMetricsPublisherForCommand(HystrixCommandKey commandKey, HystrixCommandGroupKey commandGroupKey, HystrixCommandMetrics metrics, HystrixCircuitBreaker circuitBreaker, HystrixCommandProperties properties) {
        return new HystrixYammerMetricsPublisherCommand(commandKey, commandGroupKey, metrics, circuitBreaker, properties, metricsRegistry);
    }

    @Override
    public HystrixMetricsPublisherThreadPool getMetricsPublisherForThreadPool(HystrixThreadPoolKey threadPoolKey, HystrixThreadPoolMetrics metrics, HystrixThreadPoolProperties properties) {
        return new HystrixYammerMetricsPublisherThreadPool(threadPoolKey, metrics, properties, metricsRegistry);
    }

    @Override
    public HystrixMetricsPublisherCollapser getMetricsPublisherForCollapser(HystrixCollapserKey collapserKey, HystrixCollapserMetrics metrics, HystrixCollapserProperties properties) {
        return new HystrixYammerMetricsPublisherCollapser(collapserKey, metrics, properties, metricsRegistry);
    }

HystrixYammerMetricsPublisherCommand

　　从HystrixCommandMetrics获取数据，然后设置到MetricsRegistry中。

例如：

protected void createExecutionLatencyPercentileGauge(final String name, final double percentile) {
        metricsRegistry.newGauge(createMetricName(name), new Gauge<Integer>() {
            @Override
            public Integer value() {
                return metrics.getExecutionTimePercentile(percentile);
            }
        });
    }

HystrixYammerMetricsPublisherThreadPool

　　从HystrixThreadPoolMetrics获取数据，然后设置到MetricsRegistry中。

例如：

metricsRegistry.newGauge(createMetricName("rollingMaxActiveThreads"), new Gauge<Number>() {
            @Override
            public Number value() {
                return metrics.getRollingMaxActiveThreads();
            }
        });

HystrixYammerMetricsPublisherCollapser

　　从HystrixCollapserMetrics获取数据，然后设置到MetricsRegistry中。

例如：

metricsRegistry.newGauge(createMetricName("shardSize_percentile_50"), new Gauge<Integer>() {
            @Override
            public Integer value() {
                return metrics.getShardSizePercentile(50);
            }
        });