聊聊dubbo-go的metricsFilter

/ distributedgolang / 没有评论 / 10浏览

本文主要研究一下dubbo-go的metricsFilter

metricsFilter

dubbo-go-v1.4.2/filter/filter_impl/metrics_filter.go

const (
	metricFilterName = "metrics"
)

var (
	metricFilterInstance filter.Filter
)

// must initialized before using the filter and after loading configuration
func init() {
	extension.SetFilter(metricFilterName, newMetricsFilter)
}

// metricFilter will calculate the invocation's duration and the report to the reporters
// If you want to use this filter to collect the metrics,
// Adding this into your configuration file, like:
// filter: "metrics"
// metrics:
//   reporter:
//     - "your reporter" # here you should specify the reporter, for example 'prometheus'
// more info please take a look at dubbo-samples projects
type metricsFilter struct {
	reporters []metrics.Reporter
}

newMetricsFilter

dubbo-go-v1.4.2/filter/filter_impl/metrics_filter.go

func newMetricsFilter() filter.Filter {
	if metricFilterInstance == nil {
		reporterNames := config.GetMetricConfig().Reporters
		reporters := make([]metrics.Reporter, 0, len(reporterNames))
		for _, name := range reporterNames {
			reporters = append(reporters, extension.GetMetricReporter(name))
		}
		metricFilterInstance = &metricsFilter{
			reporters: reporters,
		}
	}

	return metricFilterInstance
}

Invoke

dubbo-go-v1.4.2/filter/filter_impl/metrics_filter.go

func (p *metricsFilter) Invoke(ctx context.Context, invoker protocol.Invoker, invocation protocol.Invocation) protocol.Result {
	start := time.Now()
	res := invoker.Invoke(ctx, invocation)
	end := time.Now()
	duration := end.Sub(start)
	go func() {
		for _, reporter := range p.reporters {
			reporter.Report(ctx, invoker, invocation, duration, res)
		}
	}()
	return res
}

OnResponse

dubbo-go-v1.4.2/filter/filter_impl/metrics_filter.go

func (p *metricsFilter) OnResponse(ctx context.Context, res protocol.Result, invoker protocol.Invoker, invocation protocol.Invocation) protocol.Result {
	return res
}

小结

metricsFilter的Invoke方法在invoker.Invoke(ctx, invocation)前后记录时间,最后算出duration,然异步遍历p.reporters,执行reporter.Report

doc