}, []string{"tier"}),
}

func (t *tierMetrics) Observe(tier string, dur time.Duration) {
	t.histogram.With(prometheus.Labels{"tier": tier}).Observe(dur.Seconds())
}

func (t *tierMetrics) logSuccess(tier string) {
	t.Lock()
	defer t.Unlock()

	stat := t.requestsCount[tier]
	stat.success++
	t.requestsCount[tier] = stat
}

func (t *tierMetrics) logFailure(tier string) {
	t.Lock()

		if err != nil {
			metricsLogIf(ctx, err)
			return metrics
		}
		// data usage has not captured any tier stats yet.
		if dui.TierStats == nil {
			return metrics
		}

		return dui.tierMetrics()
	})
	return mg
}

func getLocalStorageMetrics(opts MetricsGroupOpts) *MetricsGroupV2 {
	mg := &MetricsGroupV2{
		cacheInterval:    1 * time.Minute,
		metricsGroupOpts: opts,
	}